DOCSLIB.ORG

Remote Treatment of Intermittent Central Suppression Improves Quality-Of-Life Measures

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Remote Treatment of Intermittent Central Suppression Improves Quality-Of-Life Measures Optometry (2012) 83, 19-26 Remote treatment of intermittent central suppression improves quality-of-life measures Eric S. Hussey, O.D. Private Practice, Spokane, Washington. KEYWORDS Abstract Dyslexia; BACKGROUND: Intermittent central suppression (ICS) is a repetitive intermittent (‘‘on-and-off’’) loss Electronic rapid alternate of central visual sensation without strabismus or amblyopia. These repetitive seconds-long suppres- occlusion; sions have been suggested to create visual confusion and instability that would cause vision symptoms, Intermittent central contribute to reading complaints, and even impair reading. suppression; METHODS: Teacher-identified Job Corps students were diagnosed with ICS and then treated with 5-Hz Quality of life; electronic liquid crystal shutter alternate occlusion. Suppression; RESULTS: Twenty-six young adult students (19.7 6 1.6 y) had their ICS treated over 5.9 6 3.7 months. Tests of Adult Basic Suppression periods decreased in length (P , 0.0001) and ‘‘binocular’’ nonsuppressed periods increased Education in length (P , 0.0001). Overall, College of Optometrists in Vision Development (COVD) quality-of-life (QOL) scores improved (P , 0.0001), 16 reading behavior COVD QOL questions improved (P , 0.0001), and individual QOL questions improved. Posttherapy reading scores (N 5 18) improved 3.7 (6 2.6) years (P , 0.0001). CONCLUSIONS: Treating ICS with electronic alternate occlusion reduced suppression periods, in- creased binocular periods, and improved symptoms as measured in the COVD QOL questionnaire. Pos- itive changes also occurred in reading scores. These data suggest ICS should be considered a probable cause for symptoms of reading problems. Optometry 2012;83:19-26 Treatment of the visual sensory defect of suppression has suppression in the 1950s.1,2 Most of the early thought on sup- been part of optometric vision therapy since its beginning. pression diagnosis, treatment, and neuropathology, however, Louis Jaques called for the treatment of nonstrabismic comes from study of strabismus and amblyopia. For exam- ple, Bielschowsky used the term diplopiaphobia referring Disclaimer: The data and graphs in this paper were discussed in a brief to a sort of ‘‘phobic’’ cortical response to diplopia that then presentation at the Sixth International Congress of Behavioral Optometry produces suppression in strabismus.3 In their seminal work, (ICBO), Ontario, California, April 11, 2010; and at the Joint Conference 4-7 on Theoretical and Clinical Optometry (JCTCO), June 3–7, 2010, and Hubel and Wiesel discovered changes in visual neurology the Northwest Congress of Optometry, February 26–27, 2011, both at in kittens when their eyelids were sutured shut, providing Pacific University, Forest Grove, Oregon. insight into the deprivation and constant suppression of stra- Dr. Hussey is the primary inventor of the electronic rapid alternate bismus and amblyopia. However, the explanations and occlusion goggles. No commercial version is yet available. Clinical studies descriptions of strabismic/amblyopic suppression did not continue. There are no other potential commercial conflicts of interest. * Corresponding author: Eric S. Hussey, O.D., 25 W. Nora, Suite 101, fully explain nonstrabismic, nonamblyopic, intermittent cen- Spokane, WA 99205. tral suppression (ICS). Both types of suppression are visual E-mail: [email protected] sensory defects that suspend, at least for a short time, central 1529-1839/$ - see front matter Ó 2012 American Optometric Association. All rights reserved. doi:10.1016/j.optm.2011.05.009 20 Optometry, Vol 83, No 1, January 2012 visual sensation. Therefore, both represent a loss of intact Allen15 advocated alternating flicker for strabismus sup- central visual sensation. Beyond that, the 2 suppression con- pression treatment using flashing lights alternating in a ditions show almost as many dissimilarities as similarities.8 square-wave pattern at 9 Hz. The 9-Hz alternation rate Strabismic/amblyopic (constant) suppression is viewed was thought to make use of the 9-Hz Bartley phenomenon often as a constant cortically based inhibitory loss of central, brightness enhancement, theorized to represent improved and possibly paracentral, visual sensation.9 In unilateral transmission of the visual signal to the cortex.15 Similarly, constant (strabismic/amblyopic) suppression, occlusion of electronically controlled liquid crystal shutter lenses the sighting eye will override the inhibition of the visual neu- (see Figure 1) can serve as the visual flicker-producing rology and ‘‘force’’ the strabismic/amblyopic eye to see, at tool, producing a rapid alternate occlusion rather than least while the normally sighting eye is covered. Some alter- bright flashing. The strongest, most efficient antisuppres- nation occurs in alternating strabismus, but usually with a sion alternate occlusion frequency, as determined empiri- degree of patient volition. cally during a stereoscope drawing task, is approximately ICS, on the other hand, is a repetitive, intermittent (‘‘on- 5 Hz. Further, that 5-Hz alternation pace fulfills the 2 re- and-off’’) loss of central visual sensation. Although vari- quirements for an antisuppression therapy: bilateral sight able, a typical ICS ‘‘cycle’’ might consist of repetitive 2- to and motion. On-off flicker is motion in stimulus 3-second suppressions spaced by similar periods of bilat- form.16,17 Direct square-wave alternation between the eral sight. Eighty percent to 90% of ICS patients alter- eyes at that 5-Hz pace is fast enough that the central vision nate.10,11 While a strabismic patient might control an reads the signal as continuous, that is, as bilateral and with alternation, a typical ICS patient will very much act as an little central flicker. Paradoxically, then, electronic rapid al- observer in a diagnostic examination, reporting the changes ternate occlusion (or Allen’s flashing lights) delivers a in visual sensation, including alternation, but not control- strong bilateral motion stimulusdstrong enough for anti- ling them. suppression therapy. Other vision conditions that commonly accompany stra- The treatment goal of decreasing suppression in, for bismic versus ICS illustrate additional differences between example, intermittent exotropia is understandable, but what the 2 types of suppression. Strabismus and amblyopia, and is the interest in nonstrabismic, nonamblyopic ICS? Some the co-occurring suppression, often are associated with suggest a link to reading problems, possibly dyslexia. significant refractive errors.8,9 ICS patients fit very normal Strauss and Immerman,18 Annapole,19 Safra,20 Miller refractive error distributions.10 Amblyopia by definition is et al.,21 and Hussey10,11 have suggested a diagnostic link reduced acuity in 1 eye. ICS patients show very normal to reading problems. In contrast, 1 study found little inci- and equal acuities. Both strabismus and amblyopia reduce dence of ICS as described above in a university student stereopsis scores, whereas ICS patients can show normal population with good reading skills.22 Miller et al.21 and stereopsis scores.10,11 Hussey23,24 have also treated ICS and found improvements Although cortical inhibition can explain the constant in reading, quality-of-life (QOL) measures, or other visual suppression of strabismus and amblyopia, it fails to explain tasks, such as marksmanship. This current study updates a the intermittency and alternation of ICS. What cortical previous pilot study for treating ICS with electronic liquid mechanism can explain a loss of sensation that switches crystal rapid alternate occlusion in isolation at a location re- eyes, is intermittently inhibitory (that is, actively inhibitory, mote from in-office treatment availability.23 then not actively inhibitory, then actively inhibitory on the opposite side), and all of that repetitively? Further, the Subjects genesis of ICS associated with whiplash cervical trauma 12 has been documented, but without visual field defect. All subjects came from a Job Corps site in north central What strictly cortical inhibitory mechanism is there that Washington state. According to the Job Corps Web site, ‘‘Job is triggered by trauma? What traumatic cortical damage Corps is a free education and training program that helps has been documented that apparently is sufficient to inter- young people learn a career, earn a high school diploma or mittently interrupt visual sensation by traumatically pro- GED, and find and keep a good job. For eligible youth at ducing inhibition but is insufficient to produce a field defect? The putative cortical explanation of suppression fails to explain ICS.13 Active therapies for suppression, and ICS in particular, almost always involve 2 components: a bilateral (bioptic) visual environment (e.g., a stereoscope) and visual motion.14 Common techniques include cheiroscopic tracings, in which the bilateral stereoscope visual environment incorporates a moving pencil, a Brock string, in which plucking the string brings visual sensation back in a suppressed eye, and disso- ciated eye movements using a rotating visual target while Figure 1 The alternate occlusion goggles show 1 liquid crystal lens looking through dissociating prisms. occluded. Hussey Clinical Research 21 least 16 years of age, Job Corps provides the all-around skills fill out. The COVD QOL checklist has repeatedly proven a needed to succeed in a career and in life.’’25 The treatment valid and reliable symptom survey for pre- and posttherapy group of students was, at the time of original
Load more

Recommended publications
  • Management of Microtropia
    Br J Ophthalmol: first published as 10.1136/bjo.58.3.281 on 1 March 1974. Downloaded from Brit. J. Ophthal. (I974) 58, 28 I Management of microtropia J. LANG Zirich, Switzerland Microtropia or microstrabismus may be briefly described as a manifest strabismus of less than 50 with harmonious anomalous correspondence. Three forms can be distinguished: primary constant, primary decompensating, and secondary. There are three situations in which the ophthalmologist may be confronted with micro- tropia: (i) Amblyopia without strabismus; (2) Hereditary and familial strabismus; (3) Residual strabismus after surgery. This may be called secondary microtropia, for everyone will admit that in most cases of convergent strabismus perfect parallelism and bifoveal fixation are not achieved even after expert treatment. Microtropia and similar conditions were not mentioned by such well-known early copyright. practitioners as Javal, Worth, Duane, and Bielschowsky. The views of Maddox (i898), that very small angles were extremely rare, and that the natural tendency to fusion was much too strong to allow small angles to exist, appear to be typical. The first to mention small residual angles was Pugh (I936), who wrote: "A patient with monocular squint who has been trained to have equal vision in each eye and full stereoscopic vision with good amplitude of fusion may in 3 months relapse into a slight deviation http://bjo.bmj.com/ in the weaker eye and the vision retrogresses". Similar observations of small residual angles have been made by Swan, Kirschberg, Jampolsky, Gittoes-Davis, Cashell, Lyle, Broadman, and Gortz. There has been much discussion in both the British Orthoptic Journal and the American Orthoptic journal on the cause of this condition and ways of avoiding it.
    [Show full text]
  • Teacher Guide
    Neuroscience for Kids http://faculty.washington.edu/chudler/neurok.html. Our Sense of Sight: Part 2. Perceiving motion, form, and depth Visual Puzzles Featuring a “Class Experiment” and “Try Your Own Experiment” Teacher Guide WHAT STUDENTS WILL DO · TEST their depth perception using one eye and then two · CALCULATE the class averages for the test perception tests · DISCUSS the functions of depth perception · DEFINE binocular vision · IDENTIFY monocular cues for depth · DESIGN and CONDUCT further experiments on visual perception, for example: · TEST people’s ability to interpret visual illusions · CONSTRUCT and test new visual illusions · DEVISE a “minimum difference test” for visual attention 1 SETTING UP THE LAB Supplies For the Introductory Activity Two pencils or pens for each student For the Class Experiment For each group of four (or other number) students: Measuring tools (cloth tape or meter sticks) Plastic cups, beakers or other sturdy containers Small objects such as clothespins, small legos, paper clips For “Try Your Own Experiment!” Visual illusion figures, found at the end of this Teacher Guide Paper and markers or pens Rulers Other Preparations · For the Class Experiment and Do Your Own Experiment, students can write results on a plain sheet of paper. · Construct a chart on the board where data can be entered for class discussion. · Decide the size of the student groups; three is a convenient number for these experiments—a Subject, a Tester, and a Recorder. Depending on materials available, four or five students can comprise a group. · For “Try Your Own Experiment!,” prepare materials in the Supply list and put them out on an “Explore” table.
    [Show full text]
  • Visual Secret Sharing Scheme with Autostereogram*
    Visual Secret Sharing Scheme with Autostereogram* Feng Yi, Daoshun Wang** and Yiqi Dai Department of Computer Science and Technology, Tsinghua University, Beijing, 100084, China Abstract. Visual secret sharing scheme (VSSS) is a secret sharing method which decodes the secret by using the contrast ability of the human visual system. Autostereogram is a single two dimensional (2D) image which becomes a virtual three dimensional (3D) image when viewed with proper eye convergence or divergence. Combing the two technologies via human vision, this paper presents a new visual secret sharing scheme called (k, n)-VSSS with autostereogram. In the scheme, each of the shares is an autostereogram. Stacking any k shares, the secret image is recovered visually without any equipment, but no secret information is obtained with less than k shares. Keywords: visual secret sharing scheme; visual cryptography; autostereogram 1． Introduction In 1979, Blakely and Shamir[1-2] independently invented a secret sharing scheme to construct robust key management scheme. A secret sharing scheme is a method of sharing a secret among a group of participants. In 1994, Naor and Shamir[3] firstly introduced visual secret sharing * Supported by National Natural Science Foundation of China (No. 90304014) ** E-mail address: [email protected] (D.S.Wang) 1 scheme in Eurocrypt’94’’ and constructed (k, n)-threshold visual secret sharing scheme which conceals the original data in n images called shares. The original data can be recovered from the overlap of any at least k shares through the human vision without any knowledge of cryptography or cryptographic computations. With the development of the field, Droste[4] provided a new (k, n)-VSSS algorithm and introduced a model to construct the (n, n)-combinational threshold scheme.
    [Show full text]
  • Stereoscopic Therapy: Fun Or Remedy?
    STEREOSCOPIC THERAPY: FUN OR REMEDY? SARA RAPOSO Abstract (INDEPENDENT SCHOLAR , PORTUGAL ) Once the material of playful gatherings, stereoscop­ ic photographs of cities, the moon, landscapes and fashion scenes are now cherished collectors’ items that keep on inspiring new generations of enthusiasts. Nevertheless, for a stereoblind observer, a stereoscopic photograph will merely be two similar images placed side by side. The perspective created by stereoscop­ ic fusion can only be experienced by those who have binocular vision, or stereopsis. There are several caus­ es of a lack of stereopsis. They include eye disorders such as strabismus with double vision. Interestingly, stereoscopy can be used as a therapy for that con­ dition. This paper approaches this kind of therapy through the exploration of North American collections of stereoscopic charts that were used for diagnosis and training purposes until recently. Keywords. binocular vision; strabismus; amblyopia; ste- reoscopic therapy; optometry. 48 1. Binocular vision and stone (1802­1875), which “seem to have access to the visual system at the same stereopsis escaped the attention of every philos­ time and form a unitary visual impres­ opher and artist” allowed the invention sion. According to the suppression the­ Vision and the process of forming im­ of a “simple instrument” (Wheatstone, ory, both similar and dissimilar images ages, is an issue that has challenged 1838): the stereoscope. Using pictures from the two eyes engage in alternat­ the most curious minds from the time of as a tool for his study (Figure 1) and in­ ing suppression at a low level of visual Aristotle and Euclid to the present day.
    [Show full text]
  • Management of Vith Nerve Palsy-Avoiding Unnecessary Surgery
    MANAGEMENT OF VITH NERVE PALSY-AVOIDING UNNECESSARY SURGERY P. RIORDAN-E VA and J. P. LEE London SUMMARY for unrecovered VIth nerve palsy must involve a trans­ Unresolved Vlth nerve palsy that is not adequately con­ position procedure3.4. The availability of botulinum toxin trolled by an abnormal head posture or prisms can be to overcome the contracture of the ipsilateral medial rectus 5 very suitably treated by surgery. It is however essential to now allows for full tendon transplantation techniques -7, differentiate partially recovered palsies, which are with the potential for greatly increased improvements in amenable to horizontal rectus surgery, from unrecovered final fields of binocular single vision, and deferment of palsies, which must be treated initially by a vertical any necessary surgery to the medial recti, which is also muscle transposition procedure. Botulinum toxin is a likely to improve the final outcome. valuable tool in making this distinction. It also facilitates This study provides definite evidence, from a large full tendon transposition in unrecovered palsies, which series of patients, of the potential functional outcome from appears to produce the best functional outcome of all the the surgical treatment of unresolved VIth nerve palsy, transposition procedures, with a reduction in the need for together with clear guidance as to the forms of surgery that further surgery. A study of the surgical management of 12 should be undertaken in specific cases. The fundamental patients with partially recovered Vlth nerve palsy and 59 role of botulinum toxin in establishing the degree of lateral patients with unrecovered palsy provides clear guidelines rectus function and hence the correct choice of initial sur­ on how to attain a successful functional outcome with the gery, and as an adjunct to transposition surgery for unre­ minimum amount of surgery.
    [Show full text]
  • Neural Correlates of Convergence Eye Movements in Convergence Insufficiency Patients Vs
    Neural Correlates of Convergence Eye Movements in Convergence Insufficiency Patients vs. Normal Binocular Vision Controls: An fMRI Study A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Biomedical Engineering by Chirag B. Limbachia B.S.B.M.E., Wright State University, 2014 2015 Wright State University Wright State University GRADUATE SCHOOL January 18, 2016 I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPER- VISION BY Chirag B. Limbachia ENTITLED Neural Correlates of Convergence Eye Movements in Convergence Insufficiency Patients vs. Normal Binocular Vision Controls: An fMRI Study BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIRE- MENTS FOR THE DEGREE OF Master of Science in Biomedical Engineering. Nasser H. Kashou Thesis Director Jaime E. Ramirez-Vick, Ph.D., Chair, Department of Biomedical, Industrial, and Human Factors Engineering Committee on Final Examination Nasser H. Kashou, Ph.D. Marjean T. Kulp, O.D., M.S., F.A.A.O. Subhashini Ganapathy, Ph.D. Robert E.W. Fyffe, Ph.D. Vice President for Research and Dean of the Graduate School ABSTRACT Limbachia, Chirag. M.S.B.M.E., Department of Biomedical, Industrial, and Human Factor En- gineering, Wright State University, 2015. Neural Correlates of Convergence Eye Movements in Convergence Insufficiency Patients vs. Normal Binocular Vision Controls: An fMRI Study. Convergence Insufficiency is a binocular vision disorder, characterized by reduced abil- ity of performing convergence eye movements. Absence of convergence causes, eye strain, blurred vision, doubled vision, headaches, and difficulty reading due frequent loss of place. These symptoms commonly occur during near work. The purpose of this study was to quantify neural correlates associated with convergence eye movements in convergence in- sufficient (CI) patients vs.
    [Show full text]
  • Suppression and Retinal Correspondence in Intermittent Exotropia
    Downloaded from bjo.bmj.com on May 23, 2012 - Published by group.bmj.com British Journal of Ophthalmology, 1986, 70, 673-676 Suppression and retinal correspondence in intermittent exotropia JEFFREY COOPER AND CAROL DIBBLE RECORD From the Institute of Vision Research, SUNYIState College of Optometry, 100 East 24th Street, New York, New York 10010, USA SUMMARY Suppression scotomas and retinal projection (retinal correspondence) were measured in six intermittent exotropes during deviation. Measurements used red-green anaglyph stimuli presented on a black background which could be varied from 3-4 minutes of arc to 3024'. Results showed non-suppression of all points between the fovea and the diplopia point. Harmonious anomalous retinal correspondence was usually observed. Two subjects had spontaneous changes from anomalous retinal correspondence to normal retinal correspondence without a concurrent change in ocular position. Conventional testing resulted in more variable results in regard to retinal correspondence and suppression, suggesting that non-suppression and anomalous retinal corres- pondence occur when black backgrounds are used for testing. Patients with intermittent exotropia of the diverg- image and anomalous retinal correspondence (ARC) ence excess type (DE) or basic exotropia usually do in the deviated position and normal retinal corres- not complain of diplopia when their eyes are deviat- pondence (NRC) in the aligned position on the ing.' Parks2 believes that the absence of diplopia is Hering-Bielschowsky afterimage test.' due to a dense temporal hemiretinal suppression. We therefore attempted to qualify the depth of Using a technique employing Risley prisms, suppression in deviating intermittent exotropes while Jampolsky3 demonstrated that DE patients have a monitoring ocular position.
    [Show full text]
  • Relative Importance of Binocular Disparity and Motion Parallax for Depth Estimation: a Computer Vision Approach
    remote sensing Article Relative Importance of Binocular Disparity and Motion Parallax for Depth Estimation: A Computer Vision Approach Mostafa Mansour 1,2 , Pavel Davidson 1,* , Oleg Stepanov 2 and Robert Piché 1 1 Faculty of Information Technology and Communication Sciences, Tampere University, 33720 Tampere, Finland 2 Department of Information and Navigation Systems, ITMO University, 197101 St. Petersburg, Russia * Correspondence: pavel.davidson@tuni.fi Received: 4 July 2019; Accepted: 20 August 2019; Published: 23 August 2019 Abstract: Binocular disparity and motion parallax are the most important cues for depth estimation in human and computer vision. Here, we present an experimental study to evaluate the accuracy of these two cues in depth estimation to stationary objects in a static environment. Depth estimation via binocular disparity is most commonly implemented using stereo vision, which uses images from two or more cameras to triangulate and estimate distances. We use a commercial stereo camera mounted on a wheeled robot to create a depth map of the environment. The sequence of images obtained by one of these two cameras as well as the camera motion parameters serve as the input to our motion parallax-based depth estimation algorithm. The measured camera motion parameters include translational and angular velocities. Reference distance to the tracked features is provided by a LiDAR. Overall, our results show that at short distances stereo vision is more accurate, but at large distances the combination of parallax and camera motion provide better depth estimation. Therefore, by combining the two cues, one obtains depth estimation with greater range than is possible using either cue individually.
    [Show full text]
  • Care of the Patient with Accommodative and Vergence Dysfunction
    OPTOMETRIC CLINICAL PRACTICE GUIDELINE Care of the Patient with Accommodative and Vergence Dysfunction OPTOMETRY: THE PRIMARY EYE CARE PROFESSION Doctors of optometry are independent primary health care providers who examine, diagnose, treat, and manage diseases and disorders of the visual system, the eye, and associated structures as well as diagnose related systemic conditions. Optometrists provide more than two-thirds of the primary eye care services in the United States. They are more widely distributed geographically than other eye care providers and are readily accessible for the delivery of eye and vision care services. There are approximately 36,000 full-time-equivalent doctors of optometry currently in practice in the United States. Optometrists practice in more than 6,500 communities across the United States, serving as the sole primary eye care providers in more than 3,500 communities. The mission of the profession of optometry is to fulfill the vision and eye care needs of the public through clinical care, research, and education, all of which enhance the quality of life. OPTOMETRIC CLINICAL PRACTICE GUIDELINE CARE OF THE PATIENT WITH ACCOMMODATIVE AND VERGENCE DYSFUNCTION Reference Guide for Clinicians Prepared by the American Optometric Association Consensus Panel on Care of the Patient with Accommodative and Vergence Dysfunction: Jeffrey S. Cooper, M.S., O.D., Principal Author Carole R. Burns, O.D. Susan A. Cotter, O.D. Kent M. Daum, O.D., Ph.D. John R. Griffin, M.S., O.D. Mitchell M. Scheiman, O.D. Revised by: Jeffrey S. Cooper, M.S., O.D. December 2010 Reviewed by the AOA Clinical Guidelines Coordinating Committee: David A.
    [Show full text]
  • Binocular Vision
    BINOCULAR VISION Rahul Bhola, MD Pediatric Ophthalmology Fellow The University of Iowa Department of Ophthalmology & Visual Sciences posted Jan. 18, 2006, updated Jan. 23, 2006 Binocular vision is one of the hallmarks of the human race that has bestowed on it the supremacy in the hierarchy of the animal kingdom. It is an asset with normal alignment of the two eyes, but becomes a liability when the alignment is lost. Binocular Single Vision may be defined as the state of simultaneous vision, which is achieved by the coordinated use of both eyes, so that separate and slightly dissimilar images arising in each eye are appreciated as a single image by the process of fusion. Thus binocular vision implies fusion, the blending of sight from the two eyes to form a single percept. Binocular Single Vision can be: 1. Normal – Binocular Single vision can be classified as normal when it is bifoveal and there is no manifest deviation. 2. Anomalous - Binocular Single vision is anomalous when the images of the fixated object are projected from the fovea of one eye and an extrafoveal area of the other eye i.e. when the visual direction of the retinal elements has changed. A small manifest strabismus is therefore always present in anomalous Binocular Single vision. Normal Binocular Single vision requires: 1. Clear Visual Axis leading to a reasonably clear vision in both eyes 2. The ability of the retino-cortical elements to function in association with each other to promote the fusion of two slightly dissimilar images i.e. Sensory fusion. 3. The precise co-ordination of the two eyes for all direction of gazes, so that corresponding retino-cortical element are placed in a position to deal with two images i.e.
    [Show full text]
  • Dissociated Horizontal Deviation: Clinical Spectrum, Pathogenesis
    DISSOCIATED HORIZONTAL DEVIATION: CLINICAL SPECTRUM, PATHOGENESIS, EVOLUTIONARY UNDERPINNINGS, DIAGNOSIS, TREATMENT, AND POTENTIAL ROLE IN THE DEVELOPMENT OF INFANTILE ESOTROPIA (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS) BY Michael C. Brodsky MD ABSTRACT Purpose: To elucidate the pathophysiology of dissociated horizontal deviation. Methods: The reversed fixation test was performed prospectively in 28 patients who developed consecutive exotropia following horizontal extraocular muscle surgery for infantile esotropia. All patients were assessed for the presence of adduction weakness, latent nystagmus, dissociated vertical divergence, and neurologic disease. Results: A positive reversed fixation test, indicating the presence of dissociated horizontal deviation, was found in 14 of 28 patients (50%) with consecutive exotropia. In patients with dissociated horizontal deviation, the exodeviation was usually smaller with the nonpreferred eye fixating than with the preferred eye fixating, and smaller with the preferred eye fixating than during periods of visual inattention or under general anesthesia. Dissociated horizontal deviation correlated with the findings of dissociated vertical divergence, but not with asymmetric adduction weakness, latent nystagmus, or neurologic disease. Conclusions: Using reversed fixation testing, dissociated horizontal deviation can be detected in 50% of patients who develop consecutive exotropia following surgery for infantile esotropia. In this setting, monocular fixation with either eye superimposes a dissociated esotonus upon a baseline exodeviation. Fixation with the nonpreferred eye usually exerts greater esotonus than fixation with the preferred eye, producing an asymmetrical exodeviation during prism and alternate cover testing. Depending on the baseline anatomical position of the eyes, this dissociated esotonus can manifest as an intermittent exodeviation or an intermittent esodeviation. This unrecognized form of ocular motor dissociation may contribute to the pathogenesis of infantile esotropia.
    [Show full text]
  • Construction of Autostereograms Taking Into Account Object Colors and Its Applications for Steganography
    Construction of Autostereograms Taking into Account Object Colors and its Applications for Steganography Yusuke Tsuda Yonghao Yue Tomoyuki Nishita The University of Tokyo ftsuday,yonghao,[email protected] Abstract Information on appearances of three-dimensional ob- jects are transmitted via the Internet, and displaying objects q plays an important role in a lot of areas such as movies and video games. An autostereogram is one of the ways to represent three- dimensional objects taking advantage of binocular paral- (a) SS-relation (b) OS-relation lax, by which depths of objects are perceived. In previous Figure 1. Relations on an autostereogram. methods, the colors of objects were ignored when construct- E and E indicate left and right eyes, re- ing autostereogram images. In this paper, we propose a L R spectively. (a): A pair of points on the screen method to construct autostereogram images taking into ac- and a single point on the object correspond count color variation of objects, such as shading. with each other. (b): A pair of points on the We also propose a technique to embed color informa- object and a single point on the screen cor- tion in autostereogram images. Using our technique, au- respond with each other. tostereogram images shown on a display change, and view- ers can enjoy perceiving three-dimensional object and its colors in two stages. Color information is embedded in we propose an approach to take into account color variation a monochrome autostereogram image, and colors appear of objects, such as shading. Our approach assign slightly when the correct color table is used.
    [Show full text]