2006 ANNUAL REVIEW OF THE LITERATURE

Michael T. Cron, OD1 David Goss, OD, PhD2 Dominick Maino, OD, MEd3

1. Michigan College of , 2. Indiana University School of Optometry 3. Illinois College of Optometry

As a service to the membership of the College of J. Computers/CVS/VDTs Optometrists in Vision Development and readership K. Movements of Optometry & Vision Development, a review of the L. Vision Screening literature published in other journals in the preceding M. Pediatric Pathology year is presented annually. This year’s effort, while N. Exceptional Patients attempting to provide the same level of information to O. Neuro-optometry/Neurological Insult the Optometry & Vision Development readership, has a P. Perceptual Processes revised format compared to recent annual reviews. The Q. Reading/Dyslexia citations are arranged according to topic, but include summaries of the research and descriptions of the papers rather than the previously published abstract verbatim. Accommodation and the relationship to subjective The reader can use the listed references to fi nd the symptoms with near work for young school children. abstract or the entire article if that is desired. Sterner B, Gellerstedt M, Sjöström A. Ophthal Physiol This will be the fi nal year that the journal will Opt 2006;26(2):148-55. present this annual review. Future issues of Optometry The relationship of nearpoint symptoms to & Vision Development will have articles reviewed and results of amplitude of accommodation and relative summarized within each issue as opposed to an annual accommodation tests was studied. The study subjects review format. were 72 children fi rst examined at ages ranging from The articles are chosen by the authors to be 5.8 to 10.0 years, with 59 of those children being representative of those published in the many different examined again 1.8 years later at ages ranging from journals cited in this review. It is certainly not the authors’ 7.8 to 11.8 years. Symptoms were determined by an intent that this be exhaustive and comprehensive, but oral questionnaire. Mean differences in amplitude of rather representative. accommodation by push-up method between those who The articles have been placed in the topic area where reported no symptoms and those who reported at least they appear to principally belong, recognizing certainly one symptom at the fi rst examination were 2.0 D OD, that overlap exists. The following outline of this review 2.0 D OS, and 3.1 D OU. At the second examination the may prove helpful in perusing or if searching for a differences were 3.6 D OD, 3.4 D OS, and 3.9 D OU. particular topic area. Amplitude of accommodation and negative relative A. Accommodation accommodation showed signifi cant relationships to the B. Binocular Dysfunction presence of at least one symptom, but positive relative C. Stereopsis accommodation did not. D. E. Infl uence of accommodative lag upon the F. far-gradient measurement of accommodative G. Refractive Status convergence to accommodation ratio in strabismic H. Visual Acuity patients. Miyata M, Hasebe S, Ohtsuki H. Japan J I. Ophthalmol 2006;50(5):438-42. Correspondence regarding this annual review should be emailed to Michael_ Gradient stimulus and gradient response AC/A ratios [email protected] or sent to Dr. Michael Cron, Michigan College of Optome- were measured using a distance target and -3.00 D add try at Ferris State University, 1310 Cramer Circle, Big Rapids, MI 49307. All in 63 patients with strabismus, ranging in age from 7 statements are the author’s personal opinion and may not refl ect the opinions of the College of Optometrists in Vision Development, Optometry and Vision to 34 years. The angle of strabismus at distance in the 63 Development or any institution or organization to which he may be affi liated. patients ranged from 60 prism diopters of exotropia to 40 Copyright 2006 College of Optometrists in Vision Development. prism diopters of esotropia. Accommodative response Cron MT, Goss D, Maino DM. Annual review of the literature 2006. Optom measurements were taken with a WV-500 autorefractor, Vis Dev 2007; (38)4:161-184. an infrared autorefractor with infrared refl ecting mirror in

Volume 38/Number 4/2007 161 front of the patient to allow open viewing. Convergence accommodative stimulus but were not signifi cantly was measured with prism on the alternating . different between the three refractive groups. At high The mean gradient stimulus AC/A ratio was 3.2 prism accommodative stimulus with the minus add series, diopters per diopter (SD=2.7). The mean gradient progressing myopes tended to have the highest lags of response AC/A ratio was 5.8 prism diopters per diopter accommodation and emmetropes the lowest, with non- (SD=4.3). The mean accommodative response to the - progressing myopes in between. 3.00 D lens at distance was 1.94 D (range, 0.86 to 2.87 D), with patients with tending to show lower Ocular motor triad with single vision contact lenses accommodative responses. The response AC/A ratio compared to spectacle lenses. Hunt OA, Wolffsohn JS, was on average 41% greater than the stimulus AC/A García-Resúa C. Cont Lens Ant Eye 2006;29(5):239- ratio. 45. Thirty subjects with a mean age of 21.0 years had Accommodative facility in with and without accommodation and measured with infrared myopia. Pandian A, Sankaridurg PR, Naduvilath T, automated instruments while viewing targets at O’Leary D, Sweeney DF, Rose K, Mitchell P. Invest accommodative stimulus levels of 0.1, 0.5, 1.0, 2.0, 3.0, Ophthalmol Vis Sci 2006;47(11):4725-31. 4.0, and 5.0 D. These measurements were taken while Monocular (right eye) accommodative facility wearing full correction for in spectacles at 3 m and 33 cm with semiautomated fl ippers were and in contact lenses. Experimental results confi rm compared in different refractive groups. The fl ipper theoretical calculations that persons with myopia exert lenses were plano/-2.0 D for 3 m and +2/-2 D for 33 more accommodative effort with contact lenses than cm. The defi nition of emmetropia for the separation into with spectacles, and persons with hyperopia exert less groups was cycloplegic spherical equivalent refractive accommodative effort with contact lenses than with error ranging from -0.50 to +1.50 D. Mean facility rates spectacles. Similarly persons with myopia exert greater at 3 m were 5.5 cpm for myopes (n=20, SD=2.0), 6.9 vergence effort with contact lenses than with spectacles, cpm for emmetropes (n=977, SD=1.7), and 6.9 cpm for and persons with hyperopia less. hyperopes (n=331, SD=1.7). Rates were signifi cantly lower in myopes than in non-myopes. Mean facility Accommodation functions: co-dependency and rates at 33 cm were 6.4 cpm for myopes (n=20, SD=1.8), relationship to refractive error. Allen PM, O’Leary 7.0 cpm for emmetropes (n=977, SD=1.5), and 6.9 cpm DJ. Vis Res 2006;46(4):491-505. for hyperopes (n=331, SD=1.5). Differences between Various accommodative functions were measured in groups were not statistically signifi cant for the near 64 young adults, ranging in age from 18 to 22 years, facility. over a twelve month period. Thirty of the subjects were classifi ed as being myopic (minus cycloplegic Accommodative stimulus response curve of autorefraction of 0.25 D or more). Results of emmetropes and myopes. Yeo ACH, Kang KK, Tang accommodation tests were correlated within groups W. Ann Acad Med Singapore 2006;35(12):868-74. but not between groups. These groups of tests were Accommodation response measurements were taken accommodative facility, accommodative response, for 17 emmetropes and 33 myopes between the ages of adaptive measures, and amplitude of accommodation. 16 and 23 years using a Grand Seiko WR-5100 open Myopes had signifi cantly lower average amplitude of view autorefractor. Eleven of the myopes were still accommodation, open-loop (pinhole) accommodation, progressing into more myopia. Accommodative stimulus and monocular accommodative facility to a -2.00 D lens was varied in three different ways: by changing distance at 6 m than non-myopes. Measures showing signifi cant (targets at 4 m, 1 m, 0.5 m, 0.33 m, and 0.25 m), by plus correlations with amount of myopia progression over adds while viewing target at 0.25 m (plus adds of +4, the twelve months were near (40 cm) monocular +3, +2, +1, and 0 D), and by minus adds while viewing accommodative facility (+2/-2) and both monocular and a target at 4 m (adds of 0, -1, -2, -3, and -4 D). Mean binocular lag of accommodation at 33 cm. slopes of the accommodative response stimulus curve in diopters of response per diopter of stimulus for the Accommodative lag before and after the onset of distance change series were 0.80 for the emmetropes, myopia. Mutti DO, Mitchell GL, Hayes JR, Jones LA, 0.78 for the non-progressing myopes, and 0.80 for the et al. Invest Ophthalmol Vis Sci 2006;47(3):837-46. progressing myopes. The mean slopes for the plus Lag of accommodation was measured under monocular add series were 0.27 for the emmetropes, 0.42 for the conditions with infrared open-view autorefractors in 568 non-progressing myopes and 0.49 for the progressing children who became myopic and 539 children who were myopes. The mean slopes for the minus add series were emmetropic. Myopia was defi ned as minus refraction 0.39 for the emmetropes, 0.29 for the non-progressing of at least -0.75 D in each meridian. Emmetropia was myopes and 0.15 for the progressing myopes. Slopes defi ned as refraction between -0.25 and +1.00 D in were signifi cantly different with the method of changing each meridian. Lag measurements were taken with the

162 Optometry and Vision Development subjects wearing their habitual refractive corrections rating subjective severity and relief of pain. Forty- while they viewed a letter target. Accommodative nine children between the ages of 7 and 16 years who stimuli were 4 D with a Badal stimulus or with a 25 had been diagnosed with accommodative insuffi ciency cm viewing distance and 2 D with a Badal system only. marked a Visual Analogue Scale before and after twelve The lag of accommodation was not signifi cantly higher weeks of wearing individually dispensed reading glasses different in the myopia groups in the year of myopia (average power, +0.75 D) for near work. The scale used onset on any of the stimulus conditions. However, the was a numerical scale from 0 to 10 on which the subjects lag of accommodation was signifi cantly higher in the were instructed to mark on the continuum line between myopia group than in the emmetropia group after the numbers in response to the question, “If 0 equals no onset of myopia. Those differences ranged from 0.13 to problems when doing near work and 10 equals the worst 0.56 D in the fi ve years after the onset of myopia. The degree of problems, what number would you grade your authors suggested that increased lag of accommodation problems at near work to be now?” Fifteen emmetropic may be consequence instead of a cause of myopia. control subjects with no problems or other ocular conditions had a mean scale reading of 0.6 Characteristics of accommodative behavior during (SD=0.74; range, 0 to 2). The treatment subjects all had sustained reading in emmetropes and myopes. Harb scale readings between 6 and 10 before the twelve weeks E, Thorn F, Troilo D. Vis Res 2006;46(16):2581-92. of treatment. After treatment, 89.8% of the children Twenty optometry students, ages 22 to 28 years, with marked the scale between 0 and 2, and 10.2% reported normal binocular vision and stable refractive errors, symptom levels between 3 and 4 on the scale. The read from a novel displayed on a computer monitor reduction in scale reading from before to after treatment while accommodative response was measured with an was statistically signifi cant (p<0.001). eccentric infrared photorefractor. Nine of the subjects were emmetropic (refractive errors, -0.50 to +0.50 Accommodation stimulus-response function and D), and eleven were myopic. Accommodative stimuli retinal image quality. Buehren T, Collins MJ. Vis Res of 1.5, 2.5, and 3.5 D were achieved by varying the 2006;46(10):1633-45. distance of the computer monitor from the subjects. Accommodative responses and higher order aberrations Subjects with myopia were contact lens full correction were measured with a Complete Ophthalmic Analysis of refractive error during testing. The myopia group had System (COAS) wavefront sensor for accommodative a signifi cantly higher lag of accommodation than the stimuli of 0.17, 1.0, 2.0, 3.0, 4.0, and 5.0 D. Ten subjects, emmetropia group. The slope of the accommodative ages 22 to 36 years, had no signifi cant ocular disease, stimulus-response function was not signifi cantly different heterophoria within normal limits, less in the myopia and emmetropia groups, and there was a than 0.50 D, amplitude of accommodation greater than great deal of intersubject variability in slope. Variability 5 D, and similar visual acuity in the two eyes. Five of in accommodative response, measured as the mean the subjects had myopia (mean refractive error, -2.25 standard deviation of accommodative response was D) and fi ve were emmetropic (mean refractive error, greater at higher accommodative stimuli, proportional +0.05 D). A beamsplitter allowed measurements to to the magnitude of the accommodative response, and be taken while subjects viewed acuity letter targets. A greater in subjects with myopia than in emmetropic higher lead of accommodation at far and a higher lag subjects. The mean power of accommodative of accommodation at higher accommodative stimulus microfl uctuations was signifi cantly greater for higher levels, and thus a lower accommodative stimulus- accommodative stimulus and increased signifi cantly as response function slope, was found under monocular amount of myopia increased at the 3.5 D accommodative conditions compared to binocular conditions. A shift stimulus level. The number of fi xation breaks was from positive spherical aberration to negative spherical greater at the 3.5 D stimulus level than at farther aberration with increasing accommodation was found as reading distances. The mean number of fi xation breaks has been reported in several other studies. Leads and in the myopia group was signifi cantly less than in the lags of accommodation were correlated with spherical emmetropia group for accommodative stimuli of 2.5 and aberration metrics, suggesting that accommodative 3.5 D. The authors suggested that the small fl uctuations response is, in part, due to effects of spherical in the accommodative response observed in the myopic aberration. subjects could be a blur signal leading to myopia if continued over a long period of time. Dynamic measurement of accommodation and size using the portable Grand Seiko FR-5000 Evaluation of accommodative insuffi ciency with autorefractor. Wolffsohn JS, Ukai K, Gilmartin B. the Visual Analogue Scale. Abdi S, Rydberg A, Pansell Optom Vis Sci 2006;83(5):306-10. T, Brautaset R. Strabismus 2006;14(4):199-204. The video output of a Grand Seiko FR-5000 The Visual Analogue Scale, sometimes also called autorefractor was fed into a computer for comparison a Numeric Pain Scale or a Likert scale is a method of to refractive settings on a model eye. The FR-5000

Volume 38/Number 4/2007 163 is an infrared open view autorefractor in which an binocular amplitude of accommodation, and base-out to angled infrared refl ecting mirror allows the patient to blur at 40 cm, and a statistically signifi cant reduction view objects in real space rather than looking into an in Mallett associated phoria at 40 cm. Mean lag of instrument. The FR-5000 is a portable version of the accommodation changed from 0.10 D to 0.42 D. AC/ table-top Grand Seiko WV-500 autorefractor. The open A ratio (2.04 prism diopters per diopter before therapy view aspect of these autorefractors makes it possible to and 2.06 after therapy) and CA/C ratio (0.14 diopters use them for measurements of accommodation. The per prism diopter before therapy and 0.14 after therapy) separation of the measurement bars in the video output were unchanged by vision therapy. showed a high correlation with the refractive error of the model eye. However, measurements were adversely The Mallett fi xation disparity test: infl uence of test affected by misalignment and inaccuracy in instrument instructions and relationship with symptoms. Karania focusing. The results suggest that it can be useful for R, Evans BJW. Ophthal Physiol Opt 2006;26(5):507- measurements of accommodation if good eye alignment 22. is achieved. A survey of practitioners who use the Mallett associated phoria (or aligning prism) test found that BINOCULAR DYSFUNCTION the usual instructions are to ask if marker lines are aligned or not without regard to whether the lines are Are orthoptic exercises an effective treatment for moving. A study of 105 patients, 7 to 70 years of age, convergence and fusion defi ciencies? Aziz S, Cleary was performed to compare results obtained with those M, Stewart HK, Weir CR. Strabismus 2006;14(4):183- standard instructions and modifi ed instructions with 89. additional questions about whether the lines are moving. Patient records from the Orthoptic Department of the In the latter case, prism was added until the lines did Tennent Institute of in Glasgow, United not move. On near testing, the additional questioning Kingdom over a nine year period were examined. Seventy- resulted in more cases of non-zero fi xation disparity and eight patients met inclusion criteria of 6/9 visual acuity a better correlation of test results with symptoms. The or better, no prior orthoptic treatment, no strabismus results suggest that patients should be asked not only surgery, and no dyslexia. Patients ranged from 5 to 73 whether the nonius lines are aligned but also whether years of age, with a mean of 11.9 years. was either line ever appears to move. present in 65 cases, in 11, and orthophoria in one. Nearpoint of convergence was normalized in 47 of Normal values of distance heterophoria and 55 patients with initial abnormal fi ndings. Mean near fusional vergence ranges and effects of age. Álvarez point of convergence improved signifi cantly from 16.6 CP, Puell MC, Sánchez-Ramos MC, Villena C. Graefe’s to 8.4 cm in those 55 cases. Base-out fusional vergence Archive for Clinical and Experimental Ophthalmol ranges improved at distance and near for patients with 2006;244(7):821-24. exophoria: from 12.5 to 17.5 at distance and from 15.4 Distance von Graefe phoria measurements and to 24.9 at near. Base-in fusional vergence ranges did distance rotary prism vergence ranges were not improve in the patients with esophoria. Asthenopic taken in 271 non-clinical subjects. The subjects were symptoms were improved in 65 of the 78 patients. stratifi ed into six age categories: 21 to 30 years (n=57), 31 to 40 years (n=52), 41 to 50 (n=48), 51 to 60 (n=44), Effects of orthoptic treatment on the CA/C and 61 to 70 (n=43) and over 70 (n=27). Mean distance AC/A ratios in convergence insuffi ciency. Brautaset phorias ranged from 0.3 to 0.6 prism diopters exo (SDs RL, Jennings AJM. Invest Ophthalmol Vis Sci ranging from 1.8 to 3.1) in the age groups from 21 to 70 2006;47(7):2876-80. years. The mean phoria in the over 70 group was 0.2 Stimulus AC/A ratios and CA/C ratios were prism diopters eso. There was no signifi cant effect of determined before and after twelve weeks of vision age on distance phoria, nor was there an effect of age on therapy for convergence insuffi ciency. Ten subjects distance base-in break or base-out break. The average with mean age of 25.4 years participated. AC/A ratios base-in break values were between 8.6 and 9.6 prism were measured by determining the linear regression diopters in the six age groups, with SDs ranging from 2.0 slope of Maddox rod and tangent scale phorias as to 3.1. The mean base-out break fi ndings ranged from function of accommodative stimulus which was varied 16.7 to 20.3 prism diopters, with SDs from 7.3 to 9.0. by having subjects view a target at 40 cm through Statistically signifi cant changes with age were found -2.00, -1.00, 0, +1.00, and +2.00 D lens adds. CA/C in the base-in recovery (p=0.00001) and in the base- ratios were measured with refractometer measures of out recovery (p=0.0005). The mean base-in recovery accommodation using a difference of Gaussian target decreased from 5.2 prism diopters (SD=2.2) at 21 to 30 viewed at 40 cm through 0 prism and 8 prism diopters years of age to 2.7 prism diopters (SD=2.1) for subjects base-out. The vision therapy produced statistically over 70. The mean base-out recovery decreased from signifi cant improvements in near point of convergence, 8.2 prism diopters (SD=5.4) at 21 to 30 years of age to

164 Optometry and Vision Development 4.9 prism diopters (SD=7.6) for subjects over 70. Linear monocular push-up amplitude of accommodation at least regression equations fi tted to the recovery data as a 2 D below Hofstetter’s age-based norm for minimum function of age showed a decline in the base-in recovery expected amplitude of accommodation, 15-(0.25)(age). of about 0.05 prism diopters per year and a decline in the A survey with 15 questions asking about the frequency base-out recovery of about 0.07 prism diopters per year. of symptoms was administered to the subjects. The NPC was most receded in the CIwAI group. The NPC Effect of heterophoria measurement technique averages were: NBV, 2.0 cm (SD=2.1); CI, 6.2 (SD=4.1); on the clinical accommodative convergence to AI, 6.0 (SD=6.1); CIwAI, 13.3 (SD=9.4). The base-in accommodation ratio. Escalante JB, Rosenfi eld M. and base-out breaks and recoveries at 40 cm were all 3 Optom 2006;77(5):229-34. to 4 prism diopters lower on average in the CIwAI group Sixty subjects between the ages of 20 and 25 years than in the CI group. The base-in breaks and recoveries were tested at 40 cm with the von Graefe, Maddox rod, were lower by about 3 to 4 prism diopters and the base- and modifi ed Thorington dissociated phoria methods. out breaks and recoveries were higher by about 3 to 4 Phoria measurements were taken through the distance prism diopters in the AI group compared to the CI group. refractive correction and through +1.00 D and -1.00 D The average symptom scores were: NBV, 10.3 (SD=8.2); adds to determine stimulus gradient AC/A ratios. The CI, 12.9 (SD=10.6); AI, 19.7 (SD=12.7); CIwAI, 22.8 mean values of the AC/A ratios in prism diopters per (SD=12.7). The effect of AI on symptom score was diopter were 3.47 with the von Graefe method, 2.99 statistically signifi cant (p<0.001), but the effect of CI with the Maddox rod procedure, and 2.46 with modifi ed was not (p=0.16). The symptom score was signifi cantly Thorington testing. The differences were statistically higher in CIwAI than in CI (p=0.003). Because the signifi cant. The most repeatable AC/A ratios when children in the CI group were not signifi cantly more retested after at least 24 hours were those determined symptomatic than the normal binocular vision group, with the modifi ed Thorington test. the authors suggested that symptoms in many cases diagnosed as CI may be due to a co-existing AI. Comparison of subjective heterophoria testing with a phoropter and trial frame. Casillas Casillas E, Measurements of objective and subjective Rosenfi eld M. Optom Vis Sci 2006;83(4):237-41. fi xation disparity with and without a central fusion Sixty subjects between the ages of 20 and 34 years lock. Brautaset RL, Jennings JAM. Med Sci Monitor were tested at 6 m and at 40 cm with three different 2006;12(2):MT1-4. dissociated phoria procedures on two occasions at least Subjective measurements of fi xation disparity with 24 hours apart. The three testing procedures were the and without a central fusion lock were compared to Graefe test, Maddox rod test, and modifi ed Thorington objective measures of fi xation disparity. The subjective test. Each of the three tests was performed both with a measurements were made with the Sheedy distance phoropter and with a trial frame. All three testing methods Disparometer. Objective measurements were made with showed better repeatability in a trial frame than in the the scleral search coil technique. Five persons with a phoropter at both distance and near for lateral phoria mean age of 23.5 years served as subjects. The central testing. For vertical phorias, some testing conditions fusion lock was an OXO target which was centered in showed better repeatability with the phoropter and some the middle of the nonius lines when set for zero fi xation with the trial frame. disparity. Without the central fusion lock, subjective and objective fi xation disparities were signifi cantly different. Accommodative insuffi ciency is the primary With the central fusion lock, subjective and objective source of symptoms in children diagnosed with fi xation disparities were not signifi cantly different. The convergence insuffi ciency. Marran LF, DeLand PN, sizes of both the subjective fi xation disparity and the Nguyen AL. Optom Vis Sci 2006;83(5):281-89. objective fi xation disparity were smaller with the central After examination of 299 California school children fusion lock than without it. The inclusion of central (grades 4, 5 and 6), 170 were classifi ed into one of fusion lock makes subjectively determined fi xation the following categories: normal binocular vision disparity closer to the objective fi xation disparity. (NBV; n=102), convergence insuffi ciency only (CI; n=44), accommodative insuffi ciency only (AI; n=14), Double-masked randomized placebo-controlled convergence insuffi ciency with accommodative trial of the effect of prismatic corrections on rate of insuffi ciency (CIwAI; n=10). The 44 children with reading and the relationship with symptoms. O’Leary convergence insuffi ciency had (a) near exophoria CI, Evans BJW. Ophthal Physiol Opt 2006;26(6):555- greater than far exophoria by at least four prism diopters 65. and (b) failure to meet Sheard’s criterion, near positive The effect of prism correction on reading was studied fusional vergence break less than or equal to 15, and/ using the Wilkins Rate of Reading Test. Eighty subjects or a near point of convergence greater than or equal to all manifested an associated phoria on the near Mallett 6 cm. Accommodative insuffi ciency was defi ned as Unit. There were 58 subjects with exophoria (mean

Volume 38/Number 4/2007 165 age, 43 years), 15 subjects with esophoria (mean age 16 Subtle binocular vision anomalies in migraine. years), and seven subjects with vertical phoria (mean Harle DE, Evans BJW. Ophthal Physiol Opt age, 61 years). The performance of subjects on the 2006;26(6):587-96. reading test was determined with a prism power equal Results of standard clinical of binocular vision tests to that measured with the near Mallett Unit and with a were compared in 25 persons with migraine (mean control lens with zero prism power. For subjects with age, 37.5 years) and 25 control subjects (mean age, exophoria and an associated phoria of two prism diopters 36.8 years). The tests used were cover test, associated or greater, reading performance was signifi cantly better phoria, Randot stereopsis, Maddox rod, Maddox wing, with the prism. Improvement in performance was not near point of convergence, vergence facility with prism related to level of initial symptoms. The difference in fl ippers, and fusional vergence ranges. Signifi cantly reading performance with and without prism was not more persons with migraine showed a heterophoria at signifi cant in the esophoria and vertical phoria groups. 6 m with the Maddox rod, but not at near and not with either cover test or Maddox wing at either 6 m or near. Citation patterns in the optometric and Signifi cantly more persons with migraine showed a ophthalmologic clinical binocular vision literature. fi xation disparity at either 6 m or near, but the amount Goss DA. Optometry and Vision Sci 2006;83(12):895- of the Mallett aligning prism (associated phoria) was not 902. signifi cantly different in the two groups. On the Randot Citation analyses were performed on two current shapes test, stereopsis was not signifi cantly different in clinical binocular vision books from optometry and two the two groups, but it was different by the Randot circles from ophthalmology, as well as on articles published test. Near point of convergence, vergence facility, in the fi ve years from 2000 to 2004 in optometry and and fusional vergence ranges were not signifi cantly ophthalmology journals. Topical parameters used to different in the two groups. The results suggest that any choose source books and articles limited the analysis differences in migraine tend to be subtle and binocular to topics in which both professions would have the vision treatments should not be initiated solely based on same testing and treatment options within their scopes the presence of migraine. of practice, that is, nonstrabismic binocular vision disorders, diagnosis and management of nonpresbyopic STEREOPSIS accommodative disorders, and testing procedures for Real depth vs Randot stereotests. Leske DA, Birch those conditions. Both optometry and ophthalmology EE, Holmes JM. Am J Ophthalmol 2006;142(4):699- more frequently cited literature originating from 701. their own profession. The journals with the highest Performance on four different stereotests was tested in numbers of citations totaled from all sources on the 182 patients with strabismus, ages 4 to 84 years. Two of chosen topics were Optometry and Vision Science, the tests were real depth tests and two tests were Randot Ophthalmic and Physiological Optics, American Journal tests. At distance, fi ner disparities were appreciated of Ophthalmology, Investigative Ophthalmology and with the Frisby-Davis 2 distance stereotest than with Visual Science, and Optometry (Journal of the American the Distance Randot test. At near, fi ner disparities Optometric Association). This article provides objective were appreciated with the Near Frisby test than with evidence of bias in citation patterns. the Preschool Randot. The authors suggested that the Randot tests would be more appropriate for detecting Orthoptic indications for contact lens wear. Evans subtle changes in stereoacuity, while the Frisby-Davis BJW. Cont Lens Ant Eye 2006;29(4):175-81. 2 and Near Frisby real depth tests would be better for Indications for the use of contact lenses in binocular fi nding whether stereopsis is present or not and for vision anomalies are discussed. Contact lenses are the fi nding the best measurable stereopsis. preferred optical correction for anisometropia. Three illustrative cases of contact lens wear in anisometropia Assessment of a new distance Randot stereoacuity are presented. Contact lenses can also be used in cases test. Fu VLN, Birch EE, Holmes JM. J AAPOS where refractive correction helps to solve a binocular 2006;10(5):419-23. vision problem, such as in accommodative esotropia. Three stereopsis tests were performed on 23 normal A case is presented in which toric prism contact lenses children, ages 4 to 14 years; 21 normal adults, ages 20 were prescribed in esophoria. Other less common to 36 years; and 131 patients with strabismus, ages 4 potential uses of contact lenses are for occlusion in to 85 years. The tests were distance Randot, distance patching for amblyopia or in congenital to Frisby-Davis 2, and near Preschool Randot. The new reduce nystagmus amplitude. distance Randot test yielded results similar to published normative results from other stereoacuity tests. In cases where distance Randot results differed from the near Preschool Randot test, poorer stereoacuity was usually

166 Optometry and Vision Development found on the distance Randot test. In cases where distance Pretesting was performed at 50 cm with a card with no Randot results differed from the Distance Frisby-Davis stereo target being compared to a card with a raised three 2, poorer stereoacuity was usually found on the distance dimensional E to determine testability. Children who Randot test. The authors concluded that the distance responded correctly four of four or four of fi ve times Randot may be more likely to fi nd anomalies in distance were considered testable. Stereotesting was performed stereopsis that the other two tests. at distances of 50, 100, and 150 cm, which correspond to 504, 252, and 168 arc seconds, respectively. At the Effect of age on adult stereoacuity as measured by fi rst session, testability was found in 86% of three year different types of stereotest. Garnham L, Sloper JJ. Br olds, 89% of four year olds, and 93% of fi ve year olds, J Ophthalmol 2006;90(1):91-95. a signifi cant increase with age (p<0.02). At the second Stereoacuity was measured in sixty subjects, ages session, testability was established in 90% of three year 17 to 83 years, on four different stereo tests: TNO, olds, 94% of four year olds, and 98% of fi ve year olds, Titmus, Frisby near, and Frisby-Davis distance test. also a signifi cant increase with age (p=0.0001). Test- Stereoacuity decreased with age with all tests, with the retest agreement did not change with age. Spearman rank correlation coeffi cient being statistically signifi cant (p<0.001). Stereoacuity measured with the ESOTROPIA TNO test was signifi cantly different from that found Long-term motor and sensory outcomes after with each of the other tests. The median values obtained early surgery for infantile esotropia. Birch EE, Stager on the four tests were: TNO, 60 seconds of arc; Titmus, DR Sr. J AAPOS. 2006 Oct;10(5):409-13. J AAPOS. 40 seconds; Frisby near, 30 seconds; Frisby-Davis, 15 2006 Oct;10(5):409-13. seconds. None of the subjects reported diffi culty with This article discusses the timing of esotropia judgments of distance in everyday tasks such as pouring surgery and the dilemma that early surgery may yield a drink into a cup. Fusional vergence ranges and near better sensory outcomes whereas later surgery may point of convergence were also measured. Near point of result in better alignment. They report the results of 50 convergence, base in range at distance, base in range at consecutive children enrolled in a prospective study near, and base out range for near did not show signifi cant who had surgery by 6 months of age and were followed correlations with age. Base out range at distance did for 4-17 years. Results from this early surgery group show a signifi cant correlation with age (p<0.05), with it were compared with a concurrently recruited cohort averaging just a few prism diopters less for 70 to 83 year who had surgery at 7-12 months (n=78). Both groups olds than for 17 to 29 year olds. had similar postoperative alignment and had similar rates of additional surgery. However, more children in Stereopsis in refractive surgery. Kirwan C, O’Keefe the early-surgery group had peripheral fusion (p < 0.02), M. Am J Ophthalmol 2006;142(2):218-22. central fusion (p< 0.01), Randot stereopsis (< 0.003), Eighty-three patients, ages 19 to 56 years, who and Randot stereoacuity of 200 seconds or better (20% underwent either LASIK (124 eyes) or LASEK (14 vs 9%; p < 0.05). They concluded that earlier surgery eyes) had stereopsis measured before refractive surgery resulted in better fusional outcomes without a loss of and again one week or three weeks after surgery using alignment. a red-green anaglyph stereo test. Additional stereopsis determinations were made six weeks and twelve weeks Maximum motor fusion combined with one-hour after surgery in unilaterally treated patients and after preoperative prism adaptation test in patients with treatment of the second eye in bilaterally treated patients. acquired esotropia. Ela-Dalman N, Velez G, Thacker Fifty-fi ve of the patients had bilateral sequential treatment N, Britt MT, Velez FG. J AAPOS. 2006 Dec;10(6):561- and 28 patients had unilateral surgery. Thirty-two (38.6%) 64. of the patients retained fi ne stereopsis after the operation This was a retrospective study of acquired esotropes of one eye. Loss of stereopsis after treatment of one eye without amblyopia, previous surgery or oblique muscle was correlated with the amount of anisometropia present problems who underwent bilateral medial rectus muscle after the operation. All patients who underwent bilateral recessions based on the distance angle of deviation treatment regained pre-operative stereopsis after surgery measured with the maximum motor fusion test followed on the second eye. by prism adaptation test. Alternate prism and cover testing was performed after 1 hour of prism adaptation to Random Dot E stereotest: testability and reliability determine the angle of deviation for surgical correction. in 3- to 5-year-old children. Vision in Preschoolers They found that by combining the maximum motor Study Group. J AAPOS 2006;10(6):507-14. fusion and preoperative prism adaptation it afforded Three to fi ve year old children enrolled in Head Start increased amounts of medial rectus muscle recession in one of fi ve cities across the United States were subjects and decreased the risk of postoperative undercorrection in this study. Stereotesting with the Random Dot E test without increasing the risk of overcorrection. was attempted on two occasions on 1,257 children.

Volume 38/Number 4/2007 167 Strabismus surgery for elimination of bifocals in EXOTROPIA accommodative esotropia. Lueder GT, Norman AA. Timing of surgery for primary exotropia in Am J Ophthalmol 2006 Oct;142(4):632-35. children. Asjes-Tydeman WL, Groenewoud H, van der Sixteen patients with high AC/A rations who Wilt GJ. Strabismus 2006 Dec;14(4):191-97. wore bifocals to treat their accommodative esotropia This retrospective study of 60 consecutive patients underwent strabismus surgery. The surgery was planned compared alignment and sensory functions after surgery based on the results of the prism adaptation test (PAT) in children with primary exotropia who had their surgery for near esotropia without the bifocals. All patients at ages less than 7 years with those who had surgery reportedly had successful outcomes after one or two after age 7. Children who had surgery before the age surgeries. Three of 13 (23%) patients with positive PATs of seven had signifi cantly better alignment and sensory required two surgeries and two of three (67%) patients functions (p = 0.002). Also, the younger group had with negative PATs required two surgeries. Binocularity signifi cantly fewer reoperations. The authors concluded remained the same in 13 patients and improved in three that the outcomes were better in patients whose surgical patients. Glasses were eliminated entirely in half of the intervention for primary exotropia was before age 7. patients. The long-term result of slanted medial rectus Age-related distance esotropia. Mittelman D. J resection in exotropia of the convergence insuffi ciency AAPOS. 2006 Jun;10(3):212-13. type. Choi MY, Hwang JM. Eye. 2006 Nov;20(11):1279- This was a descriptive study dealing with a form 83. of acquired esotropia occurring in older adults, which This study looked at postsurgical outcomes of a the author termed age-related distance esotropia. A slanted medial rectus (MR) resection technique for retrospective consecutive case review of 26 patients with intermittent exotropia (X(T)) of the convergence this condition was performed. These patients ranged in insuffi ciency type. In all, 10 patients with an X(T) age from 62 to 91 years old with a median age of 77 greater at near than at distance by 10 prism diopters (PD) years. They were from 4 prism diopters (PD) esotropic or more were included in this prospective study. At the to 20 PD at distance and from 9 PD esotropic to 10 PD fi nal follow-up examination, all patients demonstrated an exophoric at near. None of these patients had an obvious exodeviation of 10 PD or more at distance and near, and underlying neurologic disorder, such as tumor or stroke. the exodeviation difference between distance and near Treatment was prescribing the minimum prismatic deviation was within 10 PD in fi ve of the 10 patients. The correction that eliminated distance . The author authors concluded that bilateral slanted MR resections reported that this treatment successfully eliminated the in patients with X(T) of the convergence insuffi ciency symptoms in all patients and none of them required type resulted in undercorrection in all patients. surgery. The author described this distinctive form of strabismus that occurs in older adults that is characterized by esotropia greater at distance than near. The etiology STRABISMUS of this disorder is unknown, but it is hypothetically Factors associated with childhood strabismus: secondary to anatomical changes in the and/or fi ndings from a population-based study. Robaei D, muscles associated with aging. Rose KA, Kifl ey A, Cosstick M, Ip JM, Mitchell P. Longitudinal changes in the spherical equivalent Ophthalmol 2006 Jul;113(7):1146-53. refractive error of children. with accommodative The authors aimed to describe through a population- esotropia. Lambert SR, Lynn MJ. Br J Ophthalmol 2006 based cross-sectional study the strabismus prevalence Mar;90(3):357-61. and associated factors in a representative sample of Children with accommodative esotropia had their 6-year-old Australian children. They included 1,739 spherical equivalent refractive error monitored for a children from Sydney. Cover testing was performed at mean of 4.4 years. The authors divided the 126 subjects near and distance fi xation and strabismus was defi ned into three groups based on their age at the time they as any heterotropia at near or distance fi xation, or both, received their fi rst spectacle prescription. The refraction on cover testing. Strabismus was seen in 2.8% of the was greatest in the youngest group. All groups had an population; 54% had esotropia, 29% had exotropia, 15% initial increase in spherical equivalent refraction followed had microstrabismus, and 1 child had VIth cranial nerve later by a decrease. The greatest decrease was found palsy. Prematurity was associated with a 5-fold increase in the oldest age group. The authors concluded that in the risk of esotropia. The presence of strabismus was longitudinal changes in spherical equivalent refraction signifi cantly associated with hyperopia, , for children with accommodative esotropia vary as a anisometropia, and amblyopia (P<0.0001). function of their age when spectacle wear is initiated.

168 Optometry and Vision Development Prevalence and development of strabismus in 10- REFRACTIVE STATUS year-old premature children: a population-based A cohort study of incident myopia in Singaporean study. Holmström G, Rydberg A, Larsson E. J Pediatr children. Saw SM, Shankar A, Tan SB, Taylor H, Tan Ophthalmol Strabismus 2006 Nov-Dec;43(6):346-52. DTH, Stone RA, Wong TY. Invest Ophthalmol Vis Sci The authors looked at the prevalence and development 2006;47(5):1839-44. of strabismus, at 10 years, in children born prematurely. Singaporean Chinese children, ages 7 to 9 years, Their study included 216 premature and 217 full-term without myopia were followed over a three year period. children from the same geographic area. They found Myopia was defi ned as a minus spherical equivalent of strabismus in 16.2% of the premature children and at least 0.75 D on cycloplegic autorefraction. A total only 3.2% of the full-term children. They found some of 994 children participated in the study. When results signifi cant risk factors for strabismus at age 10, including were controlled for age, gender, parental income, books anisometropia at 6 months and spherical equivalent read per week, and intelligence quotient (IQ), relative refractive errors (i.e., >+3 D or < -3 D) at 2.5 years. The risk of developing myopia was 1.55 for two myopic conclusion was that children born prematurely have a parents versus no myopic parents. The relative risk for greater risk of strabismus at age 10 than children born incidence of myopia was 1.50 for IQ in the third tertile at term. versus IQ in the fi rst tertile. Reading as measured by books read per week was not signifi cantly associated The cost utility of strabismus surgery in adults. with the incidence of myopia. Beauchamp CL, Beauchamp GR, Stager DR Sr, Brown MM, Brown GC, Felius J. J AAPOS. 2006 Oct;10(5):394- The possible effect of undercorrection on myopic 99. progression in children. Adler D, Millodot M. Clin Cost-utility analysis is a methodology that evaluates Exp Optom 2006;89(5):315-21. the cost of medical care in relation to the gain in a measure Forty-eight children with myopia, ages six to referred to as quality-adjusted life years (QALYs). The fi fteen years, were followed for 18 months after being authors set out to develop a cost model for surgical care randomly assigned to a full correction group (n=23) for adult strabismus. Interviews were conducted with or a 0.50 D undercorrection group (n=25). Mean ages adult patients before and after strabismus surgery. Their of the subjects were 10.24 years (SD=2.18) in the cost model resulted in an estimated total cost of 4,254 full correction group and 9.93 (SD=2.66) years in the dollars per case, and a signifi cant improvement of utility undercorrection group. Mean beginning refractive errors was found. Their calculations resulted in a cost-utility for were -2.82 D (SD=1.06) in the full correction group and strabismus surgery on adults of 1,632 dollars/QALY. In -2.95 D (SD=1.25) in the undercorrection group. Mean the United States, treatments <50,000 dollars/QALY are changes in myopia over the 18 month period were -0.82 generally considered “very cost-effective.” Strabismus D (SE=0.10) in the full correction group and -0.99 D surgery in adults falls well within this range. (SE=0.09) in the undercorrection group. The difference in amount of myopia progression was not statistically Prevalence of eye disorders in young children with signifi cant at the 0.05 level by the Mann-Whitney test. eyestrain complaints. Ip JM, Robaei D, Rochtchina E, The amounts by which myopia progression was greater Mitchell P. Am J Ophthalmol 2006 Sep;142(3):495-97. in the undercorrection group than in the full correction This study attempted to determine whether eyestrain group in different classifi cations of subjects were: symptoms predict eye conditions in 6-year-old children. females, 0.20 D; males, 0.10 D; less than 3 D of myopia, Parental questionnaires and eye exams were conducted 0.13 D; 3 D of myopia or more, 0.19 D; esophoria at on 1740 children. Most children (82.3%) had a normal near, 0.19 D; orthophoria or exophoria at near, 0.13 D. eye examination, while refractive errors, amblyopia, None of those differences were statistically signifi cant. and strabismus were found in 15.0%, 3.6%, and 7.3%, The authors suggested that undercorrection was not respectively. Most children complaining of eyestrain an effective method of slowing myopia progression in had a normal eye examination; whereas most children children. with refractive error, amblyopia, or strabismus were free of eyestrain. They concluded that this complaint was a Astigmatism and its components in 6-year-old poor marker of eye conditions in young children. children. Huynh SC, Kifl ey A, Rose KA, Morgan I, et al. Invest Ophthalmol Vis Sci 2006;47(1):55-64. Refractive astigmatism and corneal astigmatism measurements were obtained for 1,765 children, ages 6 to 7 years, in Sydney, Australia. Refractive astigmatism was determined using cycloplegic autorefraction. Corneal astigmatism was calculated by converting keratometer readings into corneal powers using a refractive index of 1.3375. The prevalence of Volume 38/Number 4/2007 169 refractive astigmatism of 1.00 D or greater was 4.8%. The and myopia. Rada JAS, Shelton S, The prevalence of corneal astigmatism of 1.00 D or Norton TT. Exp Eye Res 2006;82(2):185-200. greater was 27.7%. The prevalence and mean amounts This paper reviews an extensive literature on scleral of both refractive and corneal astigmatism were greater development, biochemistry, and changes found in in East Asian and South Asian children than in European laboratory studies of myopia. The sclera is composed of Caucasian children. Refractive and corneal astigmatism collagen fi brils in irregularly arranged lamellae, along both averaged higher in children with higher amounts of with proteoglycans and glycoproteins. Scleral fi broblasts, myopia and hyperopia. which synthesize extracellular matrix, are found between the lamellae of the sclera. The sclera is a dynamic tissue Prevalence and associations of anisometropia and in which the composition of the extracellular matrix aniso-astigmatism in a population based sample of 6 can be altered and scleral remodeling can occur due to year old children. Huynh SC, Wang XY, Ip J, Robaei D, changes in visual input. Such remodeling is thought to et al. Br JOphthalmol 2006;90(5):597-601. be regulated by particular biochemical growth factors. Cycloplegic autorefraction, keratometry, The scleral thinning in high myopia appears to be a ultrasonography, and questionnaire data were analyzed consequence of this scleral remodeling. for 1,724 children with an average age of 6.7 years in Sydney, Australia. Mean spherical equivalents were Prevention of myopia progression with 0.05% +1.26 D in the right eye and +1.31 D in the left eye. The atropine solution. Lee JJ, Fang PC, Yang IH, Chen CH, prevalence of anisometropia, defi ned as a difference in et al. J Ocular Pharmacol Therap 2006;22(1):41-46. spherical equivalents between the two eyes of at least Fifty-seven children, ages 6 to 12 years, who had 1.0 D, was 1.6%. The prevalence of aniso-astigmatism, initial spherical refractive error of -0.50 to -5.50 D defi ned as a difference in astigmatism between the two participated in the study. Twenty-one children (12 boys eyes of at least 1.0 D, was 1.0%. Both anisometropia and 9 girls) had one drop of 0.05% atropine instilled and aniso-astigmatism were more common in hyperopia each evening (average initial age, 8.38 years). Thirty-six of 2.0 D or more than in hyperopia of less than 2.0 children (18 boys and 18 girls) served as a control group D. The prevalence of anisometropia was greater in (average initial age, 8.11 years). The mean spherical children with myopia than in children with hyperopia. equivalent refractive error in the treatment group was Signifi cant associations with anisometropia were found -1.58 D at the beginning of the study and -1.97 D at the with amblyopia, exotropia, and neonatal intensive care end of the study. The treatment group was followed unit admission. Signifi cant associations with aniso- for an average of 19.9 months for an average rate of astigmatism were found with amblyopia, maternal age myopia progression of -0.28 D/yr. The mean spherical greater than 35 years, and neonatal intensive care unit equivalent refractive error in the control group was -1.41 admission. Interocular differences in axial length and D at the beginning of the study and -2.76 D at the end anterior chamber depth were found in anisometropia. of the study. The treatment group was followed for an Interocular differences in corneal astigmatism were average of 21.5 months for an average rate of myopia found in aniso-astigmatism. progression of -0.75 D/yr. The rate of progression was signifi cantly lower in the treatment group than in the Longitudinal study of anisometropia in Singaporean control group (p<0.001). school children. Tong L, Chan YH, Gazzard G, Tan D, et al. Invest OphthalmolVisSci2006;47(8):3247-52. Atropine for the treatment of childhood myopia. Singaporean children, ages 7 to 9 years, underwent Chua WH, Balakrishnan V, Chan YH, Tong L, et al. annual cycloplegic autorefraction and ultrasonography Ophthalmol 2006;113(12):2285-91. over a three year period. Anisometropia was defi ned as Six to twelve year old children participated in a study a difference in spherical equivalent refractive error of at in which the treatment group subjects had unilateral least 1.00 D between the two eyes. Of 1,979 children in instillation of 1% atropine once each night and control the study, 71 (3.6%) had anisometropia at the beginning subjects had unilateral instillation of a placebo drop once of the study. An incidence of anisometropia during the each night. Three hundred forty-six subjects completed three years of the study occurred in 144 (7.55%) children. the two year study. Refractive errors were measured by The mean intereye difference in spherical equivalent cycloplegic autorefraction. At the end of two years, the refractive error was 0.29 D (SD=0.46) at the beginning average refractive change in the placebo treated eyes of the study and 0.44 D (SD=0.59) after three years. was -1.20 D (SD=0.69) and the average change in axial The change in the difference in spherical equivalent length was +0.38 mm (SD=0.38). The average change in refractive error between the two eyes was correlated two years in refractive error in the atropine treated eyes with the change in the difference in axial length between was -0.28 D (SD=0.92) with an average change in axial the two eyes (r=0.43). length of -0.02 (SD=0.35). The refractive changes in the atropine treated eyes and the placebo treated eyes were signifi cantly different. The changes in the untreated eyes

170 Optometry and Vision Development in both the atropine group and the placebo group were automated refractor. Mean depth of focus in 16 myopes similar to the changes in the eyes treated with placebo was 0.61 D (SD=0.07), compared to 0.53 D (SD=0.09) drops. in 13 emmetropes and 0.55 D (SD=0.01) in 6 hyperopes. The greater depth of focus found in myopes is consistent The Nepal longitudinal study: biometric with studies which have subjectively greater depth of characteristics of developing eyes. Garner LF, focus in myopes. These results appear to support theories Stewart AW, Owens H, Kinnear RF, et al. Optom Vis suggesting that greater amounts of retinal image defocus Sci2006;83(5):274-80. over time plays a role in myopia development. Cycloplegic autorefraction, A-scan ultrasonography, and videophakometry measurements were taken over Retinal image quality, reading and myopia. Collins an eight year period on the left eyes of 895 Tibetan MJ, Buehren T, Iskander DR. Vis Res 2006;46(1-2):196- children, ages 6 to 18 years. Subjects were classifi ed as 215. being myopic if the spherical equivalent refractive error A Complete Ophthalmic Analysis System (COAS) showed more than 0.50 D of myopia. All other subjects Hartmann-Shack wavefront sensor was used to study were classifi ed as nonmyopic. Differences between the modulation transfer functions, higher order aberrations, myopia and nonmyopia groups in the rates of change in and retinal image quality in 40 adult subjects. Twenty the biometric characteristics of the eye were as follows: of the subjects were myopic with spherical equivalent decrease in anterior chamber depth, 0.012 mm/yr greater refractive errors ranging from -1.00 to -7.50 D and in myopia group; increase in vitreous depth, 0.084 mm/yr ages ranging from 19 to 24 years. These subjects were greater in myopia group; increase in anterior crystalline continuing to progress into myopia, averaging a change lens radius, 0.073 mm/yr greater in myopia group; of -0.73 D over the last two years. Another group of increase in posterior crystalline lens radius, 0.017 mm/ 20 subjects was emmetropic, with spherical equivalent yr greater in myopia group; decrease in crystalline lens refractive errors of -0.25 to +0.25 D and ages of 19 to thickness, 0.005 mm/yr greater in myopia group; and 28 years. All subjects wore best sphere and cylinder decrease in crystalline lens power, 0.059 D/yr greater in correction during testing. Testing was done with myopia group. The rate of change in corneal radius was fi xation at 5.5 m and at the subjects’ habitual reading equivalent in the myopia and nonmyopia groups, but distance before and after reading a novel for two hours. the was steeper by 0.09 mm in the myopia group The myopia group had mean leads of accommodation than in the nonmyopia group at all ages (p<0.001). for far of 0.23 D before reading and 0.31 D after reading, and had mean lags of accommodation of 0.72 D before Depth-of-focus of the human eye: theory reading and 0.60 D after reading. The emmetropia and clinical implications. Wang B, Ciuffreda KJ. group had mean leads of accommodation for far of 0.09 SurvOphthalmol 2006;51(1):75-85. D before reading and 0.15 D after reading, and had This review paper examines the factors which affect mean lags of accommodation of 0.50 D before reading the depth of focus of the human eye and the implications and 0.47 D after reading. A consistent fi nding of poorer of depth of focus for clinical measurements and clinical retinal image quality for near than for far was observed care. Factors external to the individual which affect depth in both groups before reading. Retinal image quality at of focus are luminance, contrast, spatial frequency, detail, far declined after reading and often was slightly better and wavelength of the visual target and test environment. for near than for far after reading. Calculated depth Internal factors affecting depth of focus are visual acuity, of focus was greater in the myopia group than in the pupil size, retinal eccentricity, refractive state, and age. emmetropia group. Analyses of the relationship between Depth of focus can affect results of clinical tests which various metrics of image quality and the lead or lag of require judgments of clarity and blur. Examples include accommodation tended to show moderate correlations, subjective refraction, amplitude of accommodation, and suggesting that accommodative response is affected relative accommodation. Depth of focus affects lag or in part by the infl uence of higher order aberrations on lead of accommodation. Depth of focus is often a factor retinal image quality. in ophthalmic lens design, but its potential effects in refractive surgery haven’t been fully examined. Depth Objective real-time measurement of instrument of focus can be adversely affected by various retinal myopia in microscopists under different viewing and cortical conditions, such as amblyopia or macular conditions. Ting PWK, Schmid KL, Lam CSY, Edwards degeneration. MH. Vis Res 2006;46(15):2354-62. Instrument myopia was measured with an infrared Objective blur thresholds in free space for different photorefractor during microscopy work in 20 refractive groups. Vasudevan B, Ciuffreda KJ, Wang B. inexperienced microscopists (age range, 21 to 30 years; Curr Eye Res 2006;31(2):111-18. mean age, 24.1 years) and 10 experienced microscopists Objective depth of focus was measured in 35 young (age range, 26 to 34 years; mean age, 31.2 years). The adults, ages 20 to 35 years, using a Power Refractor II average microscopy work experience in the experienced

Volume 38/Number 4/2007 171 subjects was 4.8 years. Beamsplitters were used to take AMBLYOPIA photorefractor measurements during the microscopy Decreased cortical activation in response to a tasks. Measurements were taken under different motion stimulus in anisometropic amblyopic eyes viewing conditions and different microscope settings using functional magnetic resonance imaging. by changing whether spectacle correction was used, and Bonhomme GR, Liu GT, Miki A, Francis E, et al. J varying target quality, eyepiece power, magnifi cation, AAPOS. 2006 Dec;10(6):540-6. Epub 2006 Oct 5. and illumination of the target. The mean instrument The researchers utilized functional MRI (fMRI) and myopia in inexperienced subjects was 1.98 D (SD=0.91) motion stimuli were used to study whether interocular compared to 1.38 D (SD=0.75) in experienced subjects. differences in activation are detectable in motion- The difference between inexperienced and experienced sensitive cortical areas in patients with anisometropic microscopists was statistically signifi cant (p=0.028). The amblyopia. They compared the responses in three normal level of instrument myopia did not change signifi cantly subjects with one with 20/25 acuity and suppression and with changes in viewing conditions or microscope two anisometropic amblyopes. The control subjects had settings. signifi cant fMRI activation that was comparable on the right and left; the subject with suppression responded Corneal optics after reading, microscopy, the same way. However, the anisometropes exhibited and computer work. Acta Ophthalmol (Scand) decreased extrastriate activation in their amblyopic eyes 2006;84(2):216-24. compared with the fellow eyes. Their results support Nine subjects, ages 19 to 34 years with a mean age of the hypothesis that extrastriate cortex is affected in 24 years, had testing of corneal topography after various anisometropic amblyopia. Because it was motion tasks in three sessions on separate days early in the sensitivity, it was suggestive of a magnocellular defect, morning. The tasks were reading a novel or similar text but the exact mechanism is unclear. for 60 minutes, doing microscopy work in which cell counting was done for 60 minutes, and doing Internet Effi ciency of occlusion therapy for management of browsing and email reading for 60 minutes. Corneal amblyopia in older children. Brar GS, Bandyopadhyay wavefront Zernike coeffi cients up to the fourth order S, Kaushik S, Raj S. Indian J Ophthalmol. 2006 were derived from corneal topography data collected Dec;54(4):257-60 before and after each task. The changes from reading The goal of this study was to analyze the results of full and microscopy were generally larger and more central time occlusion therapy for amblyopia in children older compared to the changes from computer work. Changes than 6 years. The treatment the children received was in both lower and higher order aberrations were different full time occlusion of the dominant eye. At initiation between the three tasks. Thus the corneal aberrations of therapy the subjects ranged in age from 6 to 20 years induced by these three tasks are different. (9.45 +/- 3.11 years). There was a fairly equal mix of strabismic amblyopes and anisometropic amblyopes. VISUAL ACUITY Eighty out of 88 eyes (90.0%) had improvement in Refraction and visual acuity measurements: what visual acuity. The response in children older than 12 are their measurement uncertainties? Smith G. Clin was reduced. The authors concluded that occlusion Exp Optom 2006;89(2):66-72. therapy yields favorable results in strabismic and/or Sources of uncertainty in refraction include depth anisometropic amblyopia, even when initiated for the of focus, uncertainty in test lens powers and vertex fi rst time after 6 years of age. After 12 years of age, distance, and errors in working distance in retinoscopy. some children may still respond to occlusion of the Calculation of the overall uncertainty based on estimates dominant eye. of the effects of those sources results in a standard deviation of 0.3 D, which would suggest a 95% confi dence Recurrence of amblyopia after occlusion therapy. interval of 0.6 D. Sources of uncertainty in visual Bhola R, Keech RV, Kutschke P, Pfeifer W, et al. acuity measurement include pupil size, accommodation, Ophthalmol 2006 Nov;113(11):2097-100. psychological factors, testing protocol, lighting, and This study was conducted to determine the stability chart design. A review of the literature on repeatability of visual acuity after a standardized occlusion regimen of visual acuity measurements suggests an uncertainty in children with strabismic and/or anisometropic of about 0.04 logMAR, which would indicate a 95% amblyopia. The subjects were four hundred forty- confi dence interval of 0.08 logMAR. nine patients younger than 10 years who underwent an occlusion trial for amblyopia and were observed until there was a recurrence of amblyopia or for a maximum of 1 year after decrease or cessation of occlusion therapy. A recurrence of amblyopia was defi ned as > or =2 logMAR levels of VA reduction or reversal of fi xation preference within 1 year after a decrease or cessation 172 Optometry and Vision Development of occlusion therapy. Of all the subjects, 27%had a signifi cant differences in thickness of the fovea or retinal recurrence of amblyopia. The recurrence was found to nerve fi ber layer were seen comparing children with be inversely correlated with patient age. Interestingly, amblyopia with those without. However, comparing the there was no statistically signifi cant association between children with anisometropic amblyopia and the children the recurrence of amblyopia and VA of the amblyopic with strabismic amblyopia, the average thicknesses of eye at the end of maximal occlusion therapy. the fovea and the retinal nerve fi ber layer thicknesses were statistically signifi cantly different. Psychosocial impact of amblyopia and its treatment: a multidisciplinary study. Koklanis K, Abel Relationship between anisometropia, patient age, LA, Aroni R. Clin Exp Ophthalmol 2006 Nov;34(8):743- and the development of amblyopia. Donahue SP. J 50. Ophthalmol 2006 Jul;142(1):132-140. Semistructured in-depth interviews were conducted This was a retrospective study of children identifi ed with children with amblyopia and their parents in an as having anisometropia by photoscreening and then attempt to identify psychosocial factors in the experience comparing percentage and depth of amblyopia with the and treatment of amblyopia. A psychological inventory children’s age. Only 14% of anisometropic children was also conducted. Dealing with stigma and the aged 1 year or younger had amblyopia. Amblyopia was perceptions and responses of peers were found to be detected in 40% of 2-year-olds, 65% of 3-year-olds, of central signifi cance to the experience of amblyopia and 76% of 5-year-olds. The depth of the amblyopia therapy. There were adverse consequences for some also increased with age. Severe amblyopia was rare children’s identity and psychosocial well-being. for children aged 0 to 3, 9% at age 4, and 14% at age Curiously, the clinical manifestations of amblyopia 5. The author concluded that younger children with did not correlate with the social implications of the anisometropia have a lower prevalence and depth of condition. The authors concluded that while clearly amblyopia than older children. By age 3, when most treatment should aim to reverse amblyopia and restore children undergo traditional screening, amblyopia has visual acuity, doctors should make efforts to minimize usually already developed, and this is another compelling any negative psychosocial consequences of treatment. argument for earlier identifi cation and intervention particularly in the case of anisometropia. Refractive eye surgery in treating functional amblyopia in children. Levenger S, Nemet P, Hirsh A, A randomized trial to evaluate 2 hours of daily Kremer I, et al. Binoc Vis Strabismus Q. 2006;21(4):231- patching for strabismic and anisometropic amblyopia 34. in children. Wallace DK; Pediatric This study reported on 11 children with stable Investigator Group, Edwards AR, Cotter SA, Beck refractions and amblyopia who underwent refractive RW, Arnold RW, Astle WF, Barnhardt CN, Birch EE, surgery (including one lenticular). Nine of the 11 had Donahue SP, Everett DF, Felius J, Holmes JM, Kraker myopia and the other two had high astigmatism. The RT, Melia M, Repka MX, Sala NA, Silbert DI, Weise surgical refractive treatment eliminated or reduced the KK. Ophthalmol 2006 Jun;113(6):904-12. anisometropia, reduced the astigmatic error, improved The goal of this randomized multicenter clinical trial vision and improved the daily function of the children. involving 46 different sites was to compare 2 hours of They reported no complications or untoward results. The daily patching (combined with 1 hour of concurrent near authors’ conclusion was that refractive surgery can be visual activities) with a control group of spectacle wear safe and effective in treating children with high myopic alone for treatment of moderate to severe amblyopia in anisometropia, high astigmatism, and high myopia. children 3 to 7 years of age. The subjects had amblyopic- Surgery can improve visual acuity in amblyopia not eye visual acuity (VA) of 20/40 to 20/400 associated with responding to routine treatment by correcting the strabismus, anisometropia, or both. Randomization of refractive error and refractive aberrations. the 180 subjects was either to 2 hours of daily patching with 1 hour of near visual activities or to spectacles Thicknesses of the fovea and retinal nerve fi ber alone (if needed). Signifi cant improvements occurred in layer in amblyopic and normal eyes in children. the patched group and the conclusion was that even after Kee SY, Lee SY, Lee YC. Korean J Ophthalmol 2006 a period of treatment with spectacles, 2 hours of daily Sep;20(3):177-81. patching combined with 1 hour of near visual activities This study was designed to compare the thicknesses modestly improved moderate to severe amblyopia in of the fovea and the retinal nerve fi ber layer in normal children 3 to 7 years old. children and children with amblyopia. Optical Coherence Tomography (OCT) was performed on 26 children (52 eyes total) with unilateral amblyopia, some due to anisometropia and some strabismus. A normal comparison group of 42 children was also evaluated. No

Volume 38/Number 4/2007 173 Treatment of anisometropic amblyopia in children 6 months, and worse best corrected initial visual acuity with refractive correction. Cotter SA; Pediatric Eye was associated with longer time to resolution. Age, Disease Investigator Group, Edwards AR, Wallace DK, initial stereoacuity, amount, and type of anisometropia Beck RW, Arnold RW, Astle WF, Barnhardt CN, Birch were not associated with time to resolution. They EE, Donahue SP, Everett DF, Felius J, Holmes JM, concluded that treatment of anisometropic amblyopia Kraker RT, Melia M, Repka MX, Sala NA, Silbert DI, with spectacles alone can be a successful option, and Weise KK. Ophthalmol 2006 Jun;113(6):895-903. that those patients treated with spectacles alone may This was a prospective, multicenter study aimed at experience a lower amblyopia recurrence rate than those assessing the effectiveness of refractive correction alone treated with occlusion therapy. for the treatment of previously untreated anisometropic amblyopia in children ages 3 to <7 years old. The COMPUTERS/CVS/VDTS authors enrolled eighty-four children 3 to <7 years old Association between occupational asthenopia and with untreated anisometropic amblyopia ranging from psycho-physiological indicators of visual strain in 20/40 to 20/250. Optimal refractive correction was workers using video display terminals. Ustinaviciene provided. Visual acuity improved with optical correction R, Januskevicius V. Med Sci Monit 2006 Jul;12(7): by > or =2 lines in 77% of the patients and resolved in CR296-301. Epub 2006 Jun 28. 27%. Improvement took up to 30 weeks for stabilization This study determined the relationship of functional criteria to be met. The outcome of their treatment was not visual strain and symptoms of asthenopia and to evaluate related to subject age, but was related to better baseline the association between subjective and objective VA and lesser amounts of anisometropia. They concluded indicators of visual strain. Visual strain was assessed using that refractive correction alone improved VA in many a questionnaire. The results noted that 88.5% of the VDT cases and results in resolution of amblyopia in at least workers complained of various vision disorders. VDT one third of 3- to <7-year-old children with previously workers who complained of worsened vision, redness untreated anisometropic amblyopia. Most cases of of the eyes, eye pain, and diplopia during work were resolution occurred with moderate (20/40-20/100) found to show more signifi cant changes in the psycho- amblyopia. However, the average 3-line improvement physiological indicators objectively refl ecting strain of in VA resulting from treatment with spectacles may the vision analyzer. It was concluded that changes in lessen the burden of subsequent amblyopia therapy for ocular and psycho-physiological function before and those with worse of amblyopia. at the end of the workday are an appropriate objective measure of visual/central nervous system strain. Unilateral and neurodevelopmental performance in preschool Monocular 3D Head Tracking to Detect Falls children. Hrisos S, Clarke MP, Kelly T, Henderson J, of Elderly People. Rougier C, Meunier J, St-Arnaud Wright CM. Br J Ophthalmol 2006 Jul;90(7):836-38. A, Rousseau J. Conf Proc IEEE Eng Med Biol Soc The authors looked into consequences of reduced 2006;1:6384-87. acuity in one eye. In particular they were concerned Faced with the growing population of seniors, with the performance of preschool children on tasks Western societies need to think about new technologies requiring visuomotor skills and visuospatial ability. In to ensure the safety of elderly people at home. Computer comparing visually normal children including normal vision provides a good solution for healthcare systems stereoacuity with the amblyopic children, some with because it allows a specifi c analysis of people behavior. normal and some with abnormal stereoacuity, they Moreover, a system based on video surveillance is found some interesting differences. Amblyopia itself particularly well adapted to detect falls. They presented did not to relate to visuomotor actions, except when a new method to detect falls using a single camera. Their associated with reduced stereoacuity. Stereoacuity had approach was based on the 3D trajectory of the head, an infl uential role in fi ne visuomotor actions and spatial which allows them to distinguish falls from normal representation in these preschool children. activities using 3D velocities. Successful treatment of anisometropic amblyopia Binocular shape constancy from novel views: the with spectacles alone. Steele AL, Bradfi eld YS, Kushner role of a priori constraints. Chan MW, Stevenson AK, BJ, France TD, et al. J AAPOS. 2006 Feb;10(1):37-43. Li Y, Pizlo Z. Percept Psychophys 2006 Oct;68(7):1124- The authors did a retrospective chart review of 39. the records of 28 patients treated successfully for Shape constancy was tested from novel views anisometropic amblyopia with glasses alone. Age, including polyhedra, polygonal lines, and points in 3- initial visual acuity and stereoacuity, and nature of D. The results show that constraints such as planarity of anisometropia were analyzed to assess associations surface contours and symmetry are critical for reliable with time required for resolution, fi nal visual acuity, shape constancy. Binocular disparity is used to correct and stereoacuity. Average time to resolution was about

174 Optometry and Vision Development monocularly reconstructed shape. They noted that, Effect of yoga on self-rated visual discomfort in monocular (but not binocular) reconstructions produced computer users. Telles S, Naveen KV, Dash M, Deginal correlate well with both monocular and binocular R, et al. Head Face Med 2006 Dec 3;2:46. performance. This suggests that binocular and monocular The authors note that dry eye appears to be the reconstructions of shapes involve similar mechanisms main contributor to the symptoms of computer vision based on monocular shape constraints. syndrome. Various yoga practices have been shown to reduce visual strain in persons with progressive myopia. Anxiety, musculoskeletal and visual disorders in This randomized controlled trial evaluated the effect of a video display terminal workers. Tomei G, Rosati MV, combination of yoga practices on self-rated symptoms on Ciarrocca M, Capozzella A, et al. Minerva Med 2006 291computer uses versus a control group. Both groups Dec;97(6):459-66. were assessed at baseline and after sixty days. The YG This study assessed musculoskeletal and visual group practiced an hour of yoga daily for fi ve days in a disorders and levels of anxiety in 2 groups of VDT week and the control group did their usual recreational operators. This study used 190 VDT operators and activities. The results indicated that after 60 days there 190 controls not assigned to VDT. For VDT operators was a signifi cantly decreased score in the YG group. the relationship between ocular and musculoskeletal symptoms was signifi cant. Their results support current EYE MOVEMENTS data about musculoskeletal and visual disorders. Ocular motor measures in migraine with and without aura. Wilkinson F, Karanovic O, Ross EC, The effect of visual training for patients with Lillakas L, Set al. Cephalalgia 2006;26(6):660-71. visual fi eld defects due to brain damage: a systematic Horizontal pursuits and saccades were measured review. Bouwmeester L, Heutink J, Lucas C. J Neurol with an infrared eye movement monitor system in three Neurosurg Psychiatr 2007 Jun;78(6):555-64. Epub 2006 groups: migraine with aura, migraine without aura, and Nov 29. controls without headaches. They were 19 subjects in This review evaluated whether systematic visual each of the three groups. Eye movement parameters training leads to (1) a restitution of the visual fi eld studied were pursuit gain (ratio of pursuit velocity to (restoration), (2) an increase in the visual search target velocity), pursuit phase (angular measure of how fi eld size or an improvement in scanning strategies much the pursuits lead ahead or lag behind the target), (compensation) and (3) a transfer of training-related saccade amplitude, saccade peak velocity, saccade improvements in activities of daily living such as latency (time between onset of stimulus and onset of reading. All studies on scanning compensatory therapy response), and saccade gain. There were no statistically (SCT) found a signifi cant effect, a signifi cant increase signifi cant differences between the three groups in any in reading speed or decrease in reading errors. It is not of the saccade or pursuit parameters. The results suggest clear to what extent patients benefi t from restoration that visual abnormalities reported in migraine are not the therapy in relation to a more effi cient scanning strategy. result of abnormal saccades or pursuits. No single study has given a satisfactory answer. SCT seems to provide a more successful rehabilitation with Age-related changes of vergence under natural simple and user-friendly training techniques. SCT is viewing conditions. Rambold H, Neumann G, Sander recommended until the effect of the VRT is defi ned. T, Helmchen C. Neurobiol Aging 2006;27(1):163-72. Vergence eye movements were measured in 32 Visualization task performance with 2D, 3D, and subjects ranging in age from 19 to 73 years. The subjects combination displays. Tory M, Kirkpatrick AE, Atkins were classifi ed into three age groups: twelve subjects 32 MS, Möller T. IEEE Trans Vis Comput Graph 2006 Jan- years of age or younger, nine subjects 33 to 55 years of Feb;12(1):2-13. age, and eleven subjects 56 years of age or older. Results This study consisted of a series of experiments that for the three groups were compared to fi nd whether there compared 2D displays, 3D displays, and combined were age-related changes in vergence eye movement 2D/3D for relative position estimation, orientation, and parameters. Under binocular conditions, there were volume of interest tasks. Their results indicated that 3D age-related decreases in peak velocity and acceleration displays can be very effective for approximate navigation and an increase in latency for a step stimulus (seven and relative positioning. 3D displays, however are not degree jump change in stimulus). Accommodative effective for precise navigation and positioning. They vergence, measured with monocular stimulation, did not also noted that major factors contributing to display show any age-related changes to a step stimulus. Under preference and usability were task characteristics, binocular conditions with a ramp or sinusoidal stimulus orientation cues, occlusion, and spatial proximity of (continuous change in stimulus at a rate of 1.5 degrees per views that were used together. second), there were no age-related changes in vergence parameters. Accommodative vergence response to

Volume 38/Number 4/2007 175 a continuous stimulus change showed an age-related Purkinje image eye trackers while head movements decrease in velocity and increase in latency. The results were minimized with a bite bar and head restraint. suggest that assessments of vergence dynamics should Subjects read sentences which were between 48 and 72 take into account patient age. characters in length and consisted of 8 to 14 words per sentence. An uncrossed fi xation disparity larger than A prospective study of the EYEPORT vision one character (0.29 degree) was present on 47% of the training system. Laukkanen H, Rabin J. Optom fi xations and a crossed fi xation disparity was present 2006;77(10):508-14. on 8% of fi xations. Vergence eye movements which Thirty-one university students with an age range served to reduce the fi xation disparity occurred during of 20 to 41 years (mean age, 25.8 years) participated the fi xations. The magnitude of those vergence eye in a study of the effects of training with the EYEPORT movements was positively correlated with duration of system. A crossover design was used with 14 of the fi xation. subjects undergoing training for three weeks and the other 17 subjects serving as controls. The during a The binocular coordination of eye movements second three week period, the 17 previously untrained during reading in children and adults. Blythe HI, subjects underwent training and the other 14 subjects Liversedge SP, Joseph HSSL, White SJ, et al. Vis Res ceasing their training. Measurements of accommodative 2006;46(22):3898-908. facility, vergence facility, reading fi xations, and reading Twelve adults, ages 18 to 21 years, and twelve comprehension were taken at baseline, three weeks, and children, ages 7 to 11 years, read text with sentences six weeks. Paired t-tests with adjustment of the statistical that were 70 to 80 characters long. The position of each signifi cance level with the Bonferroni correction eye was monitored with Purkinje image eye trackers for multiple comparisons resulted in signifi cant while head movements were minimized with a bite bar improvement in vergence facility (p<0.0001) and trends and forehead rest. Fixation disparity often was present toward improvement in reading fi xations (p<0.015), during fi xations with vergence eye movements during reading comprehension (p<0.025), and accommodative fi xation changing the fi xation disparity. For adults, at facility (p<0.035). the end of fi xation, there was alignment 48% of the time, crossed disparity 13% of the time, and uncrossed Binocular coordination of the eyes during reading. disparity 39% of the time. For children, there was 39% Liversedge SP, Rayner K, White S, Findlay JM, et al. of the time at the end of fi xation, crossed disparity 24% Curr Biol 2006;16(17):1726-29. of the time, and uncrossed disparity 37% of the time. Fifteen students at the University of Durham in The mean amount of disparity at the end of fi xation the United Kingdom had the eye position of both eyes was 1.26 characters for adults and 1.58 characters for monitored with Purkinje image eye trackers while they children, with one character being 0.29 degree. The read sentences. The sentences were all less than 73 disparity magnitude was signifi cantly greater in children characters and had a target compound noun of six, eight, than in adults (p<0.001). or ten letters. The target word was presented such that parts of the word could be seen by one eye or the other Eye movements when reading disappearing or the entire word could be seen by both eyes. Fixation text: the importance of the word to the right of with the two eyes during reading averaged 1.1 characters fi xation. Rayner K, Liversedge SP, White SJ. Vis Res apart (SD=0.8) at the beginning of fi xation and 1.0 2006;46(3):310-23. characters apart (SD=0.7) at the end of fi xation, one Fifty-six young adult native English speakers character subtending an angle of 0.29 degrees. When participated as subjects in a series of experiments in fi xation disparity was present, the lines of sight were which sentences were read and either the currently fi xated more often (93% of fi xations) divergent (uncrossed) word or the word to the right of it or both disappeared than convergent (crossed, 7% of fi xations) in relation to or was masked during fi xation. Masking was done by the text. Experiments in which the parts of the target replacing a word with Xs. Words reappeared when a word seen by each eye were varied show that control saccade was made to another word, either to the right or of saccades is yoked in the two eyes, and is computed to the left. Reading was disrupted much more when the based on a fused representation of the word rather than word to the right of fi xation disappeared or was masked being computed for each eye separately. than when the word fi xation disappeared or was masked. The duration of fi xation was less on words which were Binocular coordination of eye movements during more frequent in the reading material. reading. Liversedge SP, White SJ, Findlay JM, Rayner K. Vis Res 2006;46(15):2363-74. Binocular coordination during was tested in fi fteen students at the University of Durham in the United Kingdom. The position of each eye was monitored with

176 Optometry and Vision Development Smooth pursuit eye movements in children. are suppressing, which can be eliminated when the Salman MS, Sharpe JA, Lillikas L, Dennis M, et al. Exp strabismus is eliminated. Brain Res 2006;169(1):139-43. Smooth pursuit eye movements were recorded by VISION SCREENING infrared eye tracker in 38 children in the 8 to 19 year age Field evaluation of the Welch Allyn SureSight range. The visual targets were moved sinusoidally at a vision screener: incorporating the vision in 10 degree amplitude and a frequency of 0.25 or 0.5 Hz preschoolers study recommendations. Rowatt AJ, (cycles per second), horizontally and vertically. Mean Donahue SP, Crosby C, Hudson AC, et al. J AAPOS. pursuit gains (ratio of eye velocity to target velocity) 2007. Jun;11(3):243-8. Epub 2006 Nov 30. for horizontal movements were 0.84 at 0.25 Hz and This was a prospective Vision in Preschoolers 0.73 at 0.50 Hz. Mean gains for vertical pursuits were (VIP) study that evaluated 11 methods of screening 0.68 at 0.25 Hz and 0.45 at 0.5 Hz. Pursuit gains were and proposed referral criteria for the Welch Allyn signifi cantly higher for horizontal pursuits than for SureSight(trade mark) Vision Screener. The SureSight vertical pursuits, were signifi cantly higher for 0.25 Hz had a higher sensitivity than most other screening than for 0.5 Hz, and increased signifi cantly with age. techniques. The conclusions noted that the SureSight Horizontal pursuit gains reached reported adult levels can be used successfully for preschool screening. by mid adolescence. Right to sight: accessing eye care for adults who Improvements in performance following are learning disabled. Starling S, Willis A, Dracup optometric vision therapy in a child with dyspraxia. M, Burton M, et al.. J Intellect Disabil Res.. 2006 Hurst CMF, Van de Weyer S, Smith C, Adler PM. Dec;10(4):337-55. Ophthal PhysiolOpt 2006;26(2):199-210. Of the 146 learning disabled adults assessed, it An eight year old boy diagnosed with dyspraxia was was found that 39 percent received less eye care than given a three month course of occupational therapy and the general population. Those living with families or an eight month program of vision therapy. The diagnosis independently were signifi cantly less likely to have had of dyspraxia was made by a pediatric occupational an eye examination than people living with paid support therapist based on observed poor proprioception, delayed staff. It was also noted that 30 percent of those previously bilateral integration, and poor visual perception. Vision examined had been diagnosed with eye problems and therapy resulted in improvements in fusional vergence 43 percent of those previously prescribed glasses were ranges, accommodative facility, saccades, and pursuits. reported as unable to tolerate them. Reading level improved by four years in eleven months. Occupational therapy Sensory Integration and Praxis A comparison of patched HOTV visual acuity and Test visual and motor/visual perception subtests also photoscreening. Leman R, Clausen MM, Bates J, Stark showed improvement. L, et al.. J Sch Nurs 2006 Aug;22(4):237-43. This study compared portable acuity testing with Infantile nystagmus: current concepts in photoscreening of 1,700 preschoolers, kindergarteners, diagnosis and management. Abel LA. Clin Exp and 1st-graders. School nurses performed patched Optom2006;89(2):57-65. acuity testing and two types of photoscreening. The This is a review paper which summarizes present results indicated that using a Gateway DV-S20 digital concepts on the diagnosis and management of congenital camera was signifi cantly more sensitive to children with nystagmus. Congenital nystagmus may exist in either signifi cant vision problems. jerk or pendular form. Another form known as dual jerk nystagmus is a composite waveform of both jerk and Relationship between anisometropia, patient age, pendular oscillations. Some textbooks state that absence and the development of amblyopia. Donahue SP. Am of is an indication of congenital nystagmus, J Ophthalmo. 2006 Jul;142(1):132-40. but some patients with congenital nystagmus have This was a retrospective observational study of been reported to have oscillopsia at least occasionally. preschool children with anisometropia. The results Electroretinography and visual evoked potential testing noted that 14% of anisometropic children aged 1 year can be useful in evaluating the visual sensory pathways or younger had amblyopia. Amblyopia was detected in in childhood nystagmus. In latent nystagmus the 40% of 2-year-olds, 65% of 3-year-olds, and 76% of 5- direction of the fast phase is away from the covered eye. year-olds. Amblyopia depth increased with age. Children That change in direction of fast phase with change in with strabismus had a stable prevalence and depth of which eye is seeing is unique to congenital nystagmus. amblyopia. It was concluded that younger children Common treatment approaches include surgery, prism with anisometropia have a lower prevalence and depth spectacles, contact lenses, and vision therapy. Vision of amblyopia than older children. By age 3, when most therapy may be helpful in that strabismic patients can have a “latent-manifest latent nystagmus” when they

Volume 38/Number 4/2007 177 children undergo traditional screening, amblyopia has or less. The conclusions noted that their is considerable already developed. morbidity, fi nancial burden, and proximal causes for pediatric eye injury-related hospitalizations. Preschool vision screening in pediatric practices. Kemper AR, Clark SJ. Clin Pediatr (Phila) 2006 Anesthetic management of preschool children Apr;45(3):263-66. with penetrating eye injuries: postal survey of This study used a national sample of pediatricians pediatric anesthetists and review of the available (55% response rate) to evaluate preschool vision screening evidence. Seidel J, Dorman T. Paediatr Anaesth 2006 practices. Acuity screening for 3-year-old children was Jul;16(7):769-76. 35%, but increased for 4- (73%) and 5-year-old children Pediatric anesthetists were surveyed regarding their (66%). Few used photoscreening or autorefraction anesthesia management of a screaming child with a (8%). Noted barriers to screening were that it was too penetrating eye injury. Of those responding 21.2% had time-consuming and children are uncooperative. Half never seen a single case, 55.1% had seen <5, 17.8% reported that there should be separate reimbursement for had seen 5-10, and 5.9% had seen >10 cases. More vision screening. experienced anesthetists preferred the use of techniques without relaxants and to extubate children under The Pediatric Vision Screener III: detection of deep anesthesia. The conclusions noted that few have strabismus in children. Nassif DS, Piskun NV, Hunter extensive experience managing a penetrating eye injury DG. Arch Ophthalmol 2006 Apr;124(4):509-13. in a child Seventy-seven subjects 2 - 18 years of age received orthoptic examinations and were classifi ed as at risk A symptom survey and quality of life questionnaire for amblyopia if strabismus or anisometropia (>1.50 for nasolacrimal duct obstruction in children. Holmes diopters) was present. Subjects were then tested with JM, Leske DA, Cole SR, Chandler DL, Repka MX; the PVS. The results indicated that binocularity as Nasolacrimal Duct Obstruction Questionnaire Study determined by the PVS was greater than 65% for all Group, Silbert DI, Tien DR, Bradley EA, Sala NA, controls and less than 20% for all subjects with constant Levin EM, Hoover DL, Klimek DL, Mohney BG, Laby strabismus. All subjects with anisometropia and no DM, Lee KA, Enzenauer RW, Bacal DA, Mills MD, strabismus had binocularity scores less than 10%. Beck RW; Pediatric Eye Disease Investigator Group. Ophthalmol 2006 Sep;113(9):1675-80. Epub 2006 Jul PEDIATRIC PATHOLOGY 7. The purpose of this study was to develop and validate Systemic and ocular fi ndings in 100 patients with a new parental questionnaire addressing symptoms hypoplasia and health-related quality of life (HRQL) in childhood Garcia ML, Ty EB, Taban M, David Rothner A, et nasolacrimal duct obstruction (NLDO). The conclusions al.. J Child Neurol 2006 Nov;21(11):949-56. noted that the NLDO questionnaire is useful in In this study a retrospective record review of 100 quantifying parental perception of symptoms and HRQL patients with for the presence in childhood NLDO and that the questionnaire may have of neurologic, radiologic, and endocrine abnormalities a role in future clinical study of NLDO. was performed. It was noted that conditions previously associated with optic nerve hypoplasia and present Identifi cation of pain indicators for infants at risk in our patients included premature birth in 21%, fetal for neurological impairment: a Delphi consensus alcohol syndrome in 9%, maternal diabetes in 6%, and study. Stevens B, McGrath P, Yamada J, Gibbins S, et endocrine abnormalities in 6%. Developmental delay al.. BMC Pediatr. 2006 Feb 2;6:1. was present in 32%, cerebral palsy in 13%, and seizures The purpose of this study was to establish consensus in 12%. There was an associated neurologic abnormality about which behavioral, physiologic and contextual in 57% of patients with bilateral optic nerve hypoplasia indicators best characterize pain in infants at high, and 32% with unilateral optic nerve hypoplasia. moderate and low levels of risk for neuro-impairment. Results noted that pain indicators with the highest Pediatric eye injury-related hospitalizations in the concordance for all groups were brow bulge, facial United States. Brophy M, Sinclair SA, Hostetler SG, grimace, eye squeeze, and inconsolability. Increased Xiang H. Pediatrics 2006 Jun;117(6):e1263-71. heart rate from baseline in the moderate and severe 2.4 million eye injuries occur in the United States groups demonstrated high concordance as well. each year (35% aged 17 years or less). 3834 eye injury- related hospitalizations were analyzed. Inpatient charges for the treatment of these injuries were more than $88 million. Hospitalization for pediatric eye injuries in the US in 2000 was 8.9 per 100,000 persons aged 20 years

178 Optometry and Vision Development EXCEPTIONAL PATIENTS Visual impairment was found in 15%. 69% had strabismus Effect of CX516, an AMPA-modulating compound, and 67% refractive error. Cognitive visual dysfunction on cognition and behavior in fragile X syndrome: a was seen in 59%. They also stated that visual disorders controlled trial. Berry-Kravis E, Krause SE, Block SS, were most frequent in those with epilepsy, cerebral palsy, Guter S, et al. J Child Adolesc Psychopharmacol. 2006 and/or cognitive disability. Oct;16(5):525-40. A Phase II, 4-week randomized, double-blind, Long-term graft survival in patients with Down placebo-controlled clinical trial was conducted to syndrome after penetrating keratoplasty. Wroblewski evaluate the safety and effi cacy of the Ampakine KJ, Mader TH, Torres MF, Parmley VC, et al. Cornea compound CX516 as a potential treatment for the 2006 Oct;25(9):1026-28. underlying disorder in fragile X syndrome (FXS). This retrospective study determined the graft Cognitive and behavioral outcome measures were survival and long-term visual outcome after penetrating administered prior to and at the end of treatment, and keratoplasty (PK) for patients with Down Syndrome again at 2 weeks post treatment. The results indicated and . The results indicated that 21 PKs that there were no signifi cant improvements in memory, were performed on 18 eyes of 13 patients. Three PKs the primary outcome measure, or in secondary measures were repeated for secondary graft failure. All 18 eyes of language, attention/executive function, behavior, and had clear grafts at the patient’s last evaluation. Follow- overall functioning. This study did demonstrate that up ranged from 4 to 88 months, with a mean of 34.9 many outcome measures were reproducible in this test- months. Preoperative visual acuity was from 20/160 to retest setting for the FXS population. count fi ngers. Postoperatively, visual acuity was from 20/30 to 20/200. It was concluded that clear grafts Visual function and execution of microsaccades and improvements in visual acuity can be obtained for related to reading skills, in cerebral palsied children. patients with Down syndrome. Careful postoperative Kozeis N, Anogeianaki A, Mitova DT, Anogianakis G, follow up by care givers is very important. Mitov T, et al. Int J Neurosci. 2006 Nov;116(11):1347- 58. Laterality in persons with intellectual disability This article assesses the ability of cerebral palsy II. Hand, foot, ear, and eye laterality in persons with children to execute microsaccades. The results showed Trisomy 21 and Williams-Beuren syndrome. Gérard- that the microsaccadic skills were severely affected with Desplanches A, Deruelle C, Stefanini S, Ayoun C, Vet al. only 19% of the CP children having normal function. Dev Psychobiol 2006 Sep;48(6):482-91. 20.9% demonstrated with an oculomotor problem, This study assessed laterality in individuals with 32.4% had a visual-perceptual problem, and 27.7% had Trisomy 21 and Williams-Beuren syndrome (WBS). a combined oculomotor and visual perceptual problem. Handedness was also assessed. Those with Down CP children, in the absence of severe mental retardation, Syndrome were more frequently left- or mixed- have very poor visual skills and visual perception that handed. Individuals with WBS had intermediate scores. leads to reading diffi culties. Differences in IQ did not correlate with laterality scores. The conclusion was that laterality profi les were not the Gross and fi ne motor function and accompanying same in the two groups. impairments in cerebral palsy. Himmelmann K, Beckung E, Hagberg G, Uvebrant P. Dev Med Child Strabismus in Down syndrome. Yurdakul NS, Neurol 2006 Jun;48(6):417-23 Ugurlu S, Maden A. J Pediatr Ophthalmol Strabismus This study described gross and fi ne motor function 2006 Jan-Feb;43(1):27-30. and accompanying neurological impairments in children Fifty-seven patients with Down Syndrome were given with cerebral palsy. This study found that motor function comprehensive examinations that included an assessment differed between CP types. More severe levels correlated of ocular alignment, cycloplegic refraction and dilated with larger proportions of accompanying impairments fundus examination. The results noted that 19% had and in children born at term, to the presence of adverse strabismus (18%esotropia and 2% exotropia). Infantile peri/neonatal events. They conclude that the classifi cation esotropia was seen in 3 patients whith no signifi cant of CP should be based on CP type and motor function, refractive error. Seven of the patients had acquired since the two combine to produce a better indicator of esotropia with clinically signifi cant refractive error and total impairment. anisometropia. A higher incidence of hypermetropia was noted in patients with strabismus. The conclusions stated Vision in children with hydrocephalus. Andersson that both esotropia and hypermetropia were commonly S, Persson EK, Aring E, Lindquist B, Dutton GN, et al. seen. Dev Med Child Neurol 2006 Oct;48(10):836-41. This study noted that vision function defi cits were identifi ed in 83% of the children with hydrocephalus.

Volume 38/Number 4/2007 179 Sensory impairments and health concerns related task. Females with Turner syndrome showed problems to the degree of intellectual disability in people in generating memory-guided saccades, but not during with Down syndrome . Määttä T, Kaski M, Taanila either the predictive saccade or gap/overlap task. A, Keinänen-Kiukaanniemi S, et al. Downs Syndr Res Females with Turner syndrome, but not females with Pract 2006 Sep;11(2):78-83. fragile X, showed defi cits in visually guided saccades Individuals with Down syndrome have a number and anti-saccades. These fi ndings suggest that different of health problems, including congenital heart brain regions are affected in the two disorders, and that defect, visual impairment, hearing loss, autoimmune different pathways lead to similar cognitive phenotypes diseases, epilepsy, early-onset Alzheimer’s disease and noted for Fragile X and Turner syndromes. intellectual disability. This paper assessed the affect of impaired health on cognitive performance in those with Enhanced perfusion in eyes and cerebral perfusion Down syndrome. 129 individuals with Down syndrome defects in a patient with Fragile X Syndrome . Balci were studied. The results indicated that health issues TA, Ciftci I, Kabakus N, Aydin M. Tohoku J Exp Med were related to the individuals’ cognitive levels. Visual 2006 Oct;210(2):169-73. impairment, dental health and neurological anomalies In this study, brain perfusion single photon emission were associated with the level of intellectual disability computed tomography (SPECT) was performed on a 6 y/ and age. o Fragile X male (FXS). An enhanced uptake of HMPAO in the orbits may refl ect the pathology associated with Global and local processing in Williams syndrome, FXS, because patients with FXS might have visual- autism, and Down syndrome: perception, attention, motor abnormalities. and construction . Porter MA, Coltheart M. Dev Neuropsychol 2006;30(3):771-89. Eye movement and visual search: are there Williams Syndrome (WS), autism (AS), and Down elementary abnormalities in autism? Brenner LA, Syndrome (DS) individuals were assessed for global Turner KC, Müller RA. J Autism Dev Disord 2007 and local processing using perception, attention, and Aug;37(7):1289-309. Epub 2006 Nov 21. construction tasks. Their results suggest a bias in An atypical eye gaze is frequently observed in those attention toward local processing as well as a global with autism, but little is known about the underlying bias in attention in DS. This study fi nds support for a oculomotor abnormalities. Our review of visual search hierarchical defi cit theory in a subset of WS individuals and oculomotor systems in the healthy brain suggests but not in DS or AS. that relevant networks may be partially impaired in autism. Eye movement abnormalities may play a role in Perceptual-motor defi cits in children with Down functions known to be impaired in autism, ie: imitation syndrome: implications for intervention.. Virji-Babul and attention. Oculomotor abnormalities may play a role N, Kerns K, Zhou E, Kapur A, et al. Downs Syndr Res as a sensorimotor defect at the root of impairments in Pract 2006 Jul;10(2):74-82. later developing functional systems resulting in potential Since recent evidence suggests that motor milestones sociocommunicative defi cits. have limited predictive power for long-term motor outcomes, researchers have begun to study the Saccadic movements using eye-tracking technology underlying perceptual-motor competencies that affect in individuals with autism spectrum disorders: pilot motor behavior in those with Down syndrome. The study. Mercadante MT, Macedo EC, Baptista PM, Paula results indicate that children with Down syndrome are CS, et al.. Arq Neuropsiquiatr 2006 Sep;64(3A):559- able to make basic perceptual discriminations but show 62. impairments in the perception of complex visual motion This study assesses differences in the visual scanning cues. between pervasive developmental disorders (PDD) and controls. The results indicated that those with PDDG Ocular motor indicators of executive dysfunction had longer duration of saccadic movements for social in Fragile X and Turner syndromes. Lasker AG, pictures compared to the control group. These fi ndings Mazzocco MM, Zee DS. Brain Cog 2007 Apr;63(3):203- suggest differences in strategies between the PDD and 20. Epub 2006 Nov 14. CG groups. Fragile X and Turner syndromes are two X- chromosome-related disorders associated with executive A role for the ‘magnocellular advantage’ in visual function and visual spatial defi cits. This study used ocular impairments in neurodevelopmental and psychiatric motor paradigms to examine evidence that disruption to disorders. Laycock R, Crewther SG, Crewther DP. different neurological pathways underlies these defi cits. Neurosci Biobehav Rev 2007;31(3):363-76. Epub 2006 It was noted that females with fragile X had defi cits Dec 1. in memory-guided saccades, predictive saccades, and Abnormal visual information processing and saccades made in the overlap condition of a gap/overlap visual attention anomalies are noted in a number of

180 Optometry and Vision Development neurodevelopmental and psychiatric disorders. An help identify visual perceptual impairments in these integrated model of visual processing based on single patients. cell and human electrophysiology may allow us to better understand how the and the magnocellular The role of prefrontal cortex in visuo-spatial pathways are involved. planning: A repetitive TMS study. Basso D, Lotze M, Vitale L, Ferreri F, et al. Exp Brain Res 2006 Visual form-processing defi cits in autism. Spencer May;171(3):411-5. Epub 2006 Apr 27. JV, O’Brien JM Perception. 2006;35(8):1047-55. In this study subjects had to decide which order of Those with autism have a number of defi cits in object locations optimizes total task travel time and distance. recognition and global processing. This study compared The results indicate that, in a visuo-spatial problem- detection thresholds for children with autism, children solving task, the prefrontal cortex is involved in the with Asperger syndrome, and a matched control group. switching between heuristics during the execution of a Those with autism showed a signifi cant form-coherence plan. defi cit and a signifi cant motion-coherence defi cit, while the performance of the children with Asperger syndrome Human spatial navigation defi cits after traumatic did not differ signifi cantly from that of controls. brain injury shown in the arena maze, a virtual Morris water maze. Skelton RW, Ross SP, Nerad L, Autism and attention defi cit hyperactivity Livingstone SA. Brain Inj 2006 Feb;20(2):189-203. disorder: assessing attention and response control This study examined such visual spatial defi cits and with the integrated visual and auditory continuous conducted a detailed analysis of navigational behavior performance test. Corbett BA, Constantine LJ. Child in a virtual environment. The conclusions noted that Neuropsychol. 2006 Aug;12(4-5):335-48. virtual environments can be used to assess the presence Attention defi cit hyperactivity disorder (ADHD) have of spatial navigation defi cits after TBI. been widely reported in children with autism (ASD). This study investigated attention and response control Tracking the recovery of visuospatial attention in children with ASD, ADHD, and typical development defi cits in mild traumatic brain injury. Halterman using an Integrated Visual and Auditory Continuous CI, Langan J, Drew A, Rodriguez E, et al. Brain. 2006 Performance Test. Many children with ASD show Mar;129(Pt 3):747-53. Epub 2005 Dec 5. defi cits in visual/auditory attention and greater defi cits This study probed defi cits in the alerting, orienting in impulsivity than children with ADHD or typical and executive components of visuospatial attention development. in individuals who have mild traumatic brain injury. NEURO-OPTOMETRY/NEUROLOGICAL The fi ndings showed that the orienting and executive INSULT components were signifi cantly affected by TBI Occurrence of ocular disease in traumatic brain immediately after the injury, whereas the alerting injury in a selected sample: a retrospective analysis. component was not. Participants with mild TBI Rutner D, Kapoor N, Ciuffreda KJ, Craig S, et al. Brain recovered from the defi cits in the orienting component Inj 2006 Sep;20(10):1079-86. of attention within a week of their injury; however the This retrospective study determined the risk of defi cits in the executive component remained throughout ocular disease in a selected, visually-symptomatic the month post-injury. This study indicates that the sample of clinic patients having traumatic brain injury regions of the brain associated with the orienting and vs. cerebrovascular accident. The conclusions noted executive components of visuospatial attention are most that individuals with TBI exhibited corneal abrasions, susceptible to neural damage resulting from mild TBI. , /hordeolum, dry eye, traumatic , vitreal prolapse and optic atrophy. This is Virtual reality applications for the remapping of different from those eye problems unique to CVA, which space in neglect patients. Ansuini C, Pierno AC, Lusher included sub-conjunctival hemorrhage and . D, Castiello U. Restor Neurol Neurosci 2006;24(4- 6):431-41. The incidence of visual perceptual impairment in This article presents evidence of the potential of patients with severe traumatic brain injury. McKenna virtual reality (VR) for the assessment, training and K, Cooke DM, Fleming J, Jefferson A, et al. Brain Inj recovery of hemispatial neglect. The conclusions note 2006 May;20(5):507-18. that it is possible to re-create links between the affected This study investigated the visual perceptual and the nonaffected space in neglect patients by using impairments in patients with traumatic brain injury. The VR. Furthermore, that specifi c regions may play a conclusions noted that visual perceptual anomalies are crucial role in the recovery of space that underlies the evident in patients with severe TBI when compared to improvement of neglect patients when trained with a normative sample. Routine use of screening tools can virtual reality.

Volume 38/Number 4/2007 181 Monocular patching in subjects with right- PERCEPTUAL PROCESSES hemisphere stroke affects perceptual-attentional Handwriting diffi culties in primary school bias. Barrett AM, Burkholder S. J Rehabil Res Dev children: a search for underlying mechanisms. 2006 May-Jun;43(3):337-46. Volman MJ, van Schendel BM, Jongmans MJ. Am J In this study, 6 post-stroke subjects bisected lines while Occup Ther 2006 Jul-Aug;60(4):451-60. self-monitoring their performance via a camera/video The authors looked at perceptual-motor dysfunction apparatus. The subjects were tested with and without and cognitive planning problems and their association right and left eye patches. It was noted that patching did with the quality or speed of handwriting in children with not affect group line-bisection error, but both right and handwriting problems. When subjects with handwriting left patches decreased individual subject spatial bias. problems and a control group were tested with regard When each subject was individually, patching improved to visual perception, visual-motor integration, fi ne performance in subjects who had greater spatial biases. motor coordination, and cognitive planning abilities, the They concluded that monocular patching may primarily group with handwriting problems scored signifi cantly affect post-stroke spatial bias. lower on visual perception, visual-motor integration, fi ne motor coordination, and cognitive planning Sensory and cognitive association in older persons: in comparison with classroom controls. The only fi ndings from an older Australian population. signifi cant predictor for quality of handwriting in the Tay T, Wang JJ, Kifl ey A, Lindley R, et al. Gerontol poor handwriting group was visual-motor integration, 2006;52(6):386-94. Epub 2006 Aug 18. whereas fi ne motor coordination was the only signifi cant This study assessed the correlation between sensory predictor of quality of handwriting in the control group. and cognitive function across groups with a narrow age The authors concluded that two different mechanisms range and any independent association between sensory underlie the quality of handwriting in children with and and cognitive impairment. They found cognitive without handwriting problems, and that poor quality of impairment in 3.3% of the subjects, vision impairment handwriting of children with handwriting issues seems in 2.7% and moderate to severe hearing loss in 10.5% particularly related to a defi ciency in visual-motor of this population. The conclusions noted that they had integration. documented an age-related correlation between sensory and cognitive function in a normal ageing sample and Visuo-motor integration and control in the that their data suggested that age-related decline and human posterior parietal cortex: evidence from the effect of visual impairment on the measurement of TMS and fMRI. Iacoboni M. Neuropsychologia cognition only partly explain the association between 2006;44(13):2691-99. sensory and cognitive impairments in seniors. The posterior parietal cortex is a fundamental structure for visuo-motor integration and control. How to identify potential fallers in a stroke unit: The author interprets recent transcranial magnetic validity indexes of 4 test methods. Andersson AG, stimulation (TMS) and functional magnetic resonance Kamwendo K, Seiger A, Appelros P. J Rehabil Med imaging (fMRI) studies. The author suggests that 2006 May;38(3):186-91. these studies reveal four concepts about visual-motor This study described general characteristics of integration and the posterior parietal cortex. These are: patients with stroke who have a tendency to fall and to that the human posterior parietal cortex has enlargened determine whether certain test instruments can identify through evolution, that visual-motor control in the fallers. The conclusions noted that the Berg Balance posterior parietal cortex may be implemented by coding Scale, Stops Walking When Talking and the TUG can be primarily action goals, that the lateralization of visuo- used to evaluate which patients have a tendency to fall. motor functions in the posterior parietal cortex suggests that the left posterior parietal cortex is more concerned Impact of alertness training on spatial neglect: a with tool use and the right posterior parietal cortex is behavioural and fMRI study. Thimm M, Fink GR, Küst more concerned with imitation of the actions of others, J, Karbe H, et al. Neuropsychologia 2006;44(7):1230- and that visuo-motor inter-hemispheric transfer through 46. Epub 2005 Nov 8. parietal callosal fi bers occurs at the level of ‘motor This paper studied the effects of a 3-week intention’. computerized alertness training on chronic visuospatial hemineglect. The results show that a 3-week program of Working memory in children with reading computerized alertness training improves performance disabilities. Gathercole SE, Alloway TP, Willis C, both in alertness and neglect tests. The limited stability Adams AM. J Exp Child Psychol 2006 Mar;93(3):265- of these effects over time suggests that a 3-week 81. alertness training alone does not result in long lasting, This study investigated associations between working but refi ning the treatment protocol may lead to a more memory and both reading and mathematics abilities in a stable amelioration of neglect symptoms. sample of 46 6- to 11-year-olds with reading disabilities. 182 Optometry and Vision Development Their fi ndings suggest that working memory skills Isolating the impact of visual perception on represent an important constraint on the acquisition of dyslexics’ reading ability. Shovman MM, Ahissar M. skill and knowledge in reading and mathematics. They Vis Res 2006 Oct;46(20):3514-25. discuss possible mechanisms for the contribution of The authors initially comment that lots of data working memory to learning, and the implications for suggest phonology plays a role in dyslexia, but that educational practice. the role of vision is still highly debated. They devised a task similar to single word reading. Young adult Retinotopic effects during spatial audio-visual dyslexics, with average or above general cognitive integration. Meienbrock A, Naumer MJ, Doehrmann abilities, and controls matched for age and cognitive O, Singer W, Muckli L. Neuropsychologia 2007 Feb skills participated in the study. They measured contrast 1;45(3):531-39. thresholds for identifying unfamiliar letters, which were In order to integrate visual and auditory stimuli we chosen from an alphabet graphically similar to Hebrew need information about whether visual and auditory and English but unfamiliar to the subjects. They looked signals originate from corresponding places in the at the effects of decreasing letter size, increasing letter external world. The authors studied spatially congruent crowding and adding white noise. They found that and incongruent audio-visual (AV) stimulation. They dyslexics performed as well as controls under all test used functional magnetic resonance imaging (fMRI) conditions, and consequently concluded that, despite and found two distinct networks of cortical regions the data showing that dyslexics have marked diffi culties that processed preferentially either spatially congruent with single word reading, the cause of these diffi culties or spatially incongruent AV stimuli. Early visual areas is not a visual processing defi cit. responded preferentially to incongruent AV stimulation and higher visual areas of the temporal and parietal cortex Directional motion contrast sensitivity in responded preferentially to congruent AV stimulation. developmental dyslexia. Slaghuis WL, Ryan JF. Vis They concluded that during mismatch processing, Res 2006 Oct;46(20):3291-303. whenever a spatial mismatch is detected in multisensory In this study the researchers compared motion regions then processing resources are re-directed to low- perception for drifting gratings in two dyslexia level visual areas. classifi cation schemes: the dyseidetic, dysphonetic and READING/DYSLEXIA mixed subgroups and surface, phonological and mixed subgroups. Subjects were a sample of 32 children with Visual-evoked response, pattern dyslexia and 32 matched normal readers. Their fi ndings electroretinogram, and psychophysical magnocellular showed that there were no differences in motion direction thresholds in , optic atrophy, and dyslexia. perception between normal readers and the group with Vaegan, Hollows FC. Optom Vis Sci 2006 Jul;83(7):486- dyslexia when dyslexia was taken as a homogeneous 98. group. The direction perception was found to be normal The examiners took tests and targets designed to be in the dyseidetic and surface dyslexia subgroups but optimal for the magnocellular system and evaluated signifi cantly lowered in both mixed dyslexia subgroups. four groups: suspects and patients with early glaucoma, One unpredicted inconsistency in the fi ndings was that patients with optic nerve disease, dyslexic children, and motion direction perception was signifi cantly lowered in age-matched controls. Parvocellular-specifi c responses the dysphonetic subgroup but normal in the phonological were normal, except in cases with explicable visual acuity subgroup. In addition, they showed evidence for loss. They found a clear dichotomy and low correlations the presence of a disorder in sequential and temporal between psychophysics and electrophysiology both order processing that appeared to refl ect a problem in within and between groups. Psychophysical threshold retaining sequences of non-meaningful auditory and elevations were absent in all glaucoma groups, often large visual stimuli in short-term working memory in children in optic atrophy and small (2.5%) but highly signifi cant with dyslexia. in dyslexia. They concluded that contrast thresholds to magnocellular-specifi c stimuli were consistent in Do children with developmental dyslexia show a cortex and but VEPs were more reliable. They selective visual attention defi cit? Sireteanu R, Goebel found no VEP loss in dyslexia which suggested that C, Goertz R, et al. Strabismus. 2006 Jun;14(2):85-93. other losses seen were artifacts. They did conclude that The authors investigated the performance of children further research is needed and that maybe the frequency- with developmental dyslexia on a number of visual tasks doubling technology might be more useful clinically. requiring selective visual attention. Dyslexic children did not show the overestimation of the left visual fi eld (pseudo-neglect) characteristic of normal adult vision. The performance of dyslexic children in texture segmentation and feature search tasks was identical to that of control children matched for age, gender and

Volume 38/Number 4/2007 183 intelligence. However, when tested on conjunction Attentional shifting and the role of the dorsal tasks for orientation and form, dyslexic children showed pathway in visual word recognition. Pammer K, shorter reaction times and a dramatically increased Hansen P, Holliday I, Cornelissen P. Neuropsychologia number of errors. Differences between the two groups 2006;44(14):2926-36. decreased with increasing age. These results suggest that The authors review the dorsal visual pathway and its children with developmental dyslexia present selective role in the control of guided visual search mechanisms. defi cits in visual attention. The point out that it has been suggested recently that the dorsal visual pathway is specifi cally involved Do phonologic and rapid automatized naming in the spatial selection and sequencing required for defi cits differentially affect dyslexic children with orthographic processing in visual word recognition. and without a history of language delay? A study They manipulated the demands for spatial processing in of Italian dyslexic children. Brizzolara D, Chilosi A, a word recognition, lexical decision task. Neuroimaging Cipriani P, Di Filippo G, et al. Cogn Behav Neurol 2006 revealed high frequency right posterior parietal Sep;19(3):141-9. activation consistent with dorsal stream involvement. The authors wanted to see if phonologic and rapid This result provides neurophysiological evidence that automatized naming (RAN) defi cits were present and the dorsal visual stream may play an important role in associated in Italian dyslexic children and also whether visual word recognition and reading. The authors further they differentially affect dyslexics with and without a conclude that a plausible link between early stage history of previous language delay. Thirty-seven children theories of reading, and the magnocellular-defi cit theory were selected on the basis of a reading defi cit and were of dyslexia, which characterizes many types of reading assigned to 2 groups according to whether or not they diffi culty, was seen. had a history of early language delay. They observed that RAN defi cits were shared by most dyslexics whether they had a history of language delay or not. Phonologic defi cits were mainly associated with a previous language It’s coming... delay. They concluded that in a shallow orthography such as Italian, RAN, not phonologic defi cits, may represent the main cognitive marker of developmental dyslexia.

Screening for Meares-Irlen sensitivity in adults: ...Save the Date can assessment methods predict changes in reading speed? Hollis J, Allen PM. Ophthal Physiol Opt 2006 Nov;26(6):566-71. The authors wanted to see which of two methods of assessing candidates for colored overlays had the most practical utility. A total of 58 adults were assessed as potential candidates for colored overlays, using two methods; a questionnaire, which identifi ed self-reported previous symptoms, and a measure of perceptual distortions immediately prior to testing. Participants were classifi ed as normal, Meares-Irlen sensitive, and borderline sensitive. Reading speed was measured with and without colored overlays. Normal subjects did not show any signifi cant benefi t from reading with an overlay. A signifi cant reading advantage was found for the borderline and Meares-Irlen participants using an overlay. The authors suggest that the assessment of perceptual distortions immediately prior to measuring color preference and reading speed is the most meaningful COVD 38th Annual Meeting method of assessing pattern glare and determining the October 13-18, 2008 utility of colored overlays. Rancho Las Palmas Palm Springs, California

184 Optometry and Vision Development