Recent Developments in Visual Field Testing for Glaucoma

REVIEW

CURRENT OPINION Recent developments in visual field testing for glaucoma

Zhichao Wua,b,c and Felipe A. Medeirosa

Purpose of review Visual field testing remains one of the most important tools for characterizing and monitoring vision loss in glaucoma. Despite its current mainstream use, new developments continue to emerge on its current use and potentially better methods for its testing and analysis. This review summarizes new developments in visual field testing and, in particular, standard automated perimetry. Recent findings Evidence-based guidance has recently been provided on the impact of testing frequency on the ability to detect visual field progression. An increasing body of evidence also highlights numerous factors that can impact the interpretation of visual field results currently considered reliable (e.g. the reliability indices themselves, fixation tracking parameters, and cognitive decline). More targeted visual field testing paradigms for central and peripheral visual fields have been explored, although further work is needed to understand their role in clinical care. Exploiting retinal imaging during visual field testing with fundus-tracked perimetry shows promise for improving precision. Thresholding algorithms that account for spatial and structural information and novel analytical techniques for longitudinal data could also improve the ability to detect and monitor visual field loss. New promising methods for objective and portable assessment of visual function have also emerged. Summary New developments in visual field testing shows promise for improving this challenging, yet fundamental, clinical test for glaucoma management. Keywords glaucoma, perimetry, visual fields

INTRODUCTION field testing in clinical practice, and then finally Glaucoma is a condition characterized by a progres- review new developments in visual field testing sive loss of retinal ganglion cells (RGCs), which can and analysis. result in structural changes and visual function loss that may result in functional disability. The funda- CLINICAL FACTORS IN VISUAL FIELD mental goal of glaucoma clinical management is to TESTING prevent or significantly delay individuals from experiencing the adverse effects of this condition. Frequency of visual field testing Visual field testing using static automated perimetry (SAP) has remained an invaluable tool for detect- Detecting visual field progression in eyes with glau- ing and monitoring visual function loss associated coma continues to be a challenging task, and the with glaucoma, and for understanding how such loss relates to the level or the future risk of func- aDuke Eye Center and Department of Ophthalmology, Duke University tional disability when making clinical management b decisions [1]. School of Medicine, Durham, North Carolina, USA, Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne Despite its mainstream use in clinical practice for and cOphthalmology, Department of Surgery, The University of Mel- many decades now, important developments in bourne, Melbourne, Australia visual field testing continue to occur, highlighting Correspondence to Felipe A. Medeiros, MD, PhD, Duke Eye Center, important implications for clinicians and showing Duke University, 2351 Erwin Rd, Durham, NC 27705, USA. great promise for future clinical translation. This E-mail: [email protected] review will therefore discuss recent insights gained Curr Opin Ophthalmol 2018, 29:141–146 that are directly relevant to the current use of visual DOI:10.1097/ICU.0000000000000461

These findings also have implications for the KEY POINTS prudent idea of home-based visual field testing, Evidence-based guidance on testing frequency and an which may be possible using personal computers accumulating body of evidence on clinical factors that [4], tablet devices [5,6], or recent brain–computer && affect the interpretation of visual field test results can interfaces [7 ]. A study by Anderson et al. [8] esti- improve the clinical decision-making process. mated that the time to detect rapid visual field progression would be reduced from 2.5 years with Testing that targets central and more peripheral visual field regions has been explored, but requires further semi-annual testing to 0.9 years with weekly home- work to understand their role in the standard of care. based testing assuming a compliance rate of 63%. The two-third reduction in the time required to Fundus-tracked perimetry, a technique that exploits detect rapid visual field progression could be highly retinal imaging during visual field testing, could beneficial for some patients, although the cost-ben- improve the precision of detecting and monitoring visual field loss. efit of such an approach remains to be determined. Also, the frequency of testing required for effective Novel thresholding strategies that incorporate spatial home-monitoring may impose difficulties for sub- and structural information into its testing procedure, jective testing. and novel analytical methods for longitudinal visual field data could also improve the ability to detect and monitor visual field loss. Reliability indices and visual field variability Portable and objective methods for assessing visual Before interpreting the results of a visual field test, it function hold promise for home-based monitoring of is crucial to first determine whether the test was glaucoma patients or those suspected of disease. performed reliably, and to understand how an individual’s performance can affect the results of the test. Using the 24-2 Swedish Interactive Threshold Algorithm (SITA) standard strategy on the Hum- ability to do so is dependent on the frequency of phrey Field Analyzer (HFA; Carl Zeiss Meditec, testing, duration of follow-up, and level of measure- Inc., Dublin, California, USA), Yohannan et al. [9&] ment variability. A study by Wu et al. [2&&] recently and Tan et al. [10] both recently observed that false- provided evidence-based guidance on the impact of positive and false-negative errors improved and testing frequency on the ability to detect the pres- worsened mean deviation values, respectively, ence of visual field progression from evaluating a whereas fixation losses had little impact, when eval- large longitudinal cohort of glaucoma participants, uating a large cohort of glaucoma and normal par- highlighting that the time required to detect pro- ticipants. Rao et al. [11] demonstrated that even gression was not proportionally reduced by increas- small frequencies of false-negative errors can lead ing the number of tests performed per year. For to the erroneous classification of a visual field test as instance, visual field progression in eyes with a rapid being glaucomatous. In addition to these reliability (2 dB/year) decrease in visual field mean deviation indices, Ishiyama et al. [12,13] demonstrated that can only be detected with 80% power after 3.3, 2.4, increased tracking error or deviation (capturing and 2.1 years when testing was performed once, blinks and eye movements) quantified from the gaze twice, and three times a year, assuming a best-prac- tracking results during visual field testing were asso- tice scenario (where two baseline tests were ciated with increased point-wise visual field variabil- included, and where progression had to be repli- ity and lower mean deviation values. These findings cated on one confirmatory test). Due to the smaller collectively demonstrate how these measures of gains achieved by increasing the testing frequency visual field reliability can indicate potential system- from twice to thrice a year, semi-annual testing in atic effects on its results, even if the test itself is the initial years of follow-up was suggested as a considered reliable. reasonable compromise for having sufficient power In another study, Diniz-Filho et al. [14&] showed to rule out the presence of rapid visual field progres- how cognitive decline was associated with visual sion whilst minimizing the testing burden. How- field variability and increased error response rates ever, it is important to note that visual field on the reliability indices, and Chew et al. [15] also progression detected within approximately the first showed that a higher self-reported level of anxiety 2.5 years of semi-annual testing does not necessarily was associated with increased error response rates on indicate that rapid visual field progression is occur- reliability indices as well. Finally, a study by Arai ring, which another study also emphasized [3], et al. [16] demonstrated that ocular surface disease because the estimate of the rate of progression is increased tracking errors and deviations (that may still highly variable when including such few tests. result in poorer visual field repeatability) in a

142 www.co-ophthalmology.com Volume 29 Number 2 March 2018 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. Developments in perimetry Wu and Medeiros manner not captured by standard reliability indices. potential value of such tests in eyes with glaucoma. These studies further highlight patient-related fac- A study by Mo¨nter et al. [27&] observed in a cohort of tors that clinicians should consider when interpret- 30 glaucoma participants that there was only a ing visual field results. moderate level of agreement between central visual field sensitivity measured by SAP and peripheral visual field isopter radius measured using a fully DEVELOPMENTS IN TESTING TECHNIQUES automated kinetic perimetry approach, noting that AND ANALYSES eyes with similar central visual fields can have markedly different peripheral visual field results. Focused central and peripheral visual field On the contrary, a study by Odden et al. [28&&] testing observed in a much larger cohort of glaucoma In recent years, the nature and significance of mac- patients (n ¼ 232) that there was a strong association ular damage, even in eyes with early stages of glau- between the percentage of abnormal locations coma, has become increasingly recognized [17]. detected using the 24-2 SITA standard and 60-4 Given the importance of central visual function suprathreshold strategies on the HFA, but that sig- due to its association with self-reported quality of nificant disagreements can still be present. These life [18,19], some have more recently recommended insightful preliminary studies warrant further inves- regularly performing targeted central visual field tigations to better understand the potential value of tests, using the 10-2 strategy on the HFA for such tests in clinical practice. instance. One group has based this recommendation on findings that 24-2 summary metrics missed topographically congruent abnormalities present Fundus-tracked visual field testing on the 10-2 test and optical coherence tomography Conventional visual field testing on SAP relies on (OCT) macular scans [20], that glaucoma eyes with the ability of an individual to maintain their fixa- normal 24-2 results often had abnormal 10-2 results tion in one location throughout the test so that the [21], and the binocular mean sensitivity of the 10-2 same retinal location can be sampled throughout tests demonstrated a stronger association with the thresholding procedure. However, a previous vision-related quality of life than mean sensitivity study suggested that even fixation drifts half the of 24-2 tests [22]. However, two other studies were size of that exhibited by that of excellent fixators more reserved about the recommendation to regu- contribute substantially to the large test–retest var- larly perform 10-2 tests, on the basis that central iability often observed with SAP [29]. Recent devel- abnormalities in the 24-2 test and OCT macular opments in a technique described as fundus-tracked scans were strong predictors of abnormalities on perimetry (or ‘microperimetry’) allows the fundus to && the 10-2 test [23 ,24]. Indeed, the three previous be continuously visualized using a retinal imaging studies [20–22] that suggested that 24-2 tests were system, so that test stimuli can be accurately pre- suboptimal at detecting abnormalities detected by sented at specific retinal locations throughout a test, the 10-2 had only evaluated the results from the and for those same locations to be evaluated at a entire 24-2 test, but not within the central test subsequent test. In glaucoma eyes, studies to date locations of the 24-2. Although it would seem logi- have primarily sought to compare whether its mea- cal that the 10-2 test should perform better than the sured sensitivities are comparable with SAP [30,31] central locations on the 24-2 by virtue of its or used it to evaluate structure-function relation- increased sampling density, further studies are ships [32–34]. A study by Wu et al. [35&] sought to required to provide better evidence-based guidance evaluate the performance of fundus-tracked perime- on the role of this test in clinical practice. This is try, by densely sampling the circumpapillary region paramount since the suggestion to perhaps alternate with stimuli spaced 0.88 apart. They observed that 10-2 and 24-2 testing by previous studies [20,21] variability was highest at the border of a normal and may come at the expense of delaying the detection abnormal region; however, locations with low sen- && of noncentral visual field progression [2 ]. sitivity did not necessarily demonstrated high test– On the other extreme, it has also been recog- retest variability. This was in contrast with previous nized for decades that glaucoma eyes can have visual observations that measurement variability spans the field abnormalities outside the central 24–308 entire dynamic range in areas with visual field dam- region typically tested, even if visual field sensitivi- age [36,37], leading some to recently suggest that ties within that central region are normal [25,26]. visual field testing may be improved by restricting Given that peripheral vision is also important for the tested sensitivities to at least 15–19 dB [38–41]. daily functioning (particularly postural stability), Of note, it was hypothesized that such high levels of some recent studies have sought to evaluate the measurement variability were due to the response

1040-8738 Copyright ß 2018 Wolters Kluwer Health, Inc. All rights reserved. www.co-ophthalmology.com 143 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. Glaucoma saturation of RGCs for intense stimuli, but the find- consensus. Finally, a study by Yousefi et al. [55,56] ings from a recent study challenge this assumption demonstrated that a machine learning approach, [42]. Nonetheless, these findings highlight the being a form of artificial intelligence, also shows potential for fundus-tracked perimetry to reduce great promise for improving the detection of pro- measurement variability and possibly shorten the gression. These developments are encouraging since time required to detect visual field progression. detecting progression continues to be a challenging However, future studies are still needed to investi- task in clinical practice, but future studies are gate its clinical potential. required to compare the performance of these methods against the subjective expert evaluation of visual field progression to fully understand their value. Novel visual field thresholding strategies The reduction of measurement variability can also be achieved through better visual field thresholding New methods for assessing visual function algorithms, such as ones that account for spatial A recent study by Nakanishi et al. [7&&] describes the information. For instance, Chong et al. [43,44&] pro- development and validation of a portable brain– posed a method to automatically select test locations computer interface (nGoggle, NGoggle, Inc., San during the visual field test, in a manner that increases Diego, California, USA) for objective assessment of the sampling density around areas of visual field loss. visual function loss. The device integrates a wearable, Two other studies by Rubinstein et al. [45] and Wild wireless, dry electroencephalogram (EEG) system, et al. [46] used different approaches to exploit spatial and a head-mounted display (HMD) to allow acqui- information throughout testing to reduce testing sition of multifocal steady-state visual evoked poten- duration while maintaining the same level of preci- tial (mfSSVEP) signals in response to visual sion. In addition, studies by Denniss et al. [47] and stimulation from the HMD. The device also uses Ganeshrao et al. [48] demonstrated that using prior electro-oculogram to monitor eye fixations. The pilot structural imaging information during the thresh- investigation of accuracy consisted of 62 eyes of 33 olding procedure can also improve measurement glaucomatous patients and 30 eyes of 17 healthy precision. These studies collectively demonstrate individuals, where the nGoggle was compared to an evolution of thresholding procedures towards standard automated perimetry. In order to allow an an individualized approach, showing great promise unbiased comparison between the two instruments, for clinical translation. eyes were classified as glaucomatous according to the appearance of the optic disc. Assessment of diagnos- tic accuracy based on the area under the receiver- Improved visual field progression analysis operating characteristic (ROC) curve revealed a per- Conventionally, visual field progression is often formance that was superior for the nGoggle global performed by trend-based analysis of global mea- mfSSVEP parameter [ROC curve area 0.924, 95% sures such as mean deviation or the visual field confidence interval (CI) 0.863–0.964], versus global index (VFI), or point-wise event-based analysis using SAP parameters, such as mean deviation (ROC area the guided progression analysis (GPA) on the HFA. 0.813, 95% CI 0.716–0.896, P ¼ 0.046) and pattern For global trend-based analysis, a study by Gardiner standard deviation (ROC area 0.768, 95% CI 0.657– and Demirel [49] showed that the mean deviation 0.858, P ¼ 0.012). In the investigation of sectoral measure was more effective than VFI. To overcome measurements, the ROC curve areas were generally the high variability associated with point-wise anal- larger for nGoggle than SAP, notably for the central yses, some studies showed that cluster trend-based area, although without statistically significant differ- analyses can improve the sensitivity of detecting ence between corresponding sectors (P > 0.10 for all progression over global measures [50,51]. However, comparisons). Assessment of repeatability of nGog- more advanced techniques have been also been gle measurements was performed by collecting recently explored, with the potential to substan- repeated testing in 20 eyes of 10 glaucomatous tially improve the detection of progression beyond patients who had three sessions of measurements these current methods. For instance, Zhu et al. separated by weekly intervals between sessions. The [52,53&] showed this using an analysis that accounts average intraclass correlation coefficient (ICC) of the for nonstationary measurement variability (i.e. global mfSSVEP parameter was 0.92 (95% CI 0.82– greater variability in regions of visual field damage 0.97), whereas the mean coefficient of variation of than normal regions) and spatial correlations. War- the mfSSVEP global parameter was 3.03% (95% CI ren et al. [54] also reported that an analysis that 2.19–3.87%), indicating good repeatability. accounts for spatial correlation also better detected As a portable and objective method for assessing visual field progression as defined by clinical expert visual function, the nGoggle may be a promising

144 www.co-ophthalmology.com Volume 29 Number 2 March 2018 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. Developments in perimetry Wu and Medeiros method for diagnosing and detecting progressive Conflicts of interest visual field loss in glaucoma, in particular, when There are no conflicts of interest. applied for home-based monitoring. The device may also be useful for screening for functional loss in underserved areas. Future studies should attempt to REFERENCES AND RECOMMENDED validate its application under these settings. READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest CONCLUSION && of outstanding interest Visual field testing remains a crucial part of the 1. Saunders LJ, Medeiros FA, Weinreb RN, Zangwill LM. What rates of glau- clinical management of glaucoma, and the recent coma progression are clinically significant? Exp Rev Ophthalmol 2016; progress in understanding factors that affect visual 11:227–234. 2. Wu Z, Saunders LJ, Daga FB, et al. Frequency of testing to detect visual field results and ability to detect progression can && field progression derived using a longitudinal cohort of glaucoma patients. improve the clinical decision-making process. Con- Ophthalmology 2017; 124:786–792. The impact of the frequency of testing on detecting visual field progression was tinued research to better understand the value of evaluated and evidence-based guidance for clinical practice was provided, high- targeted visual field testing paradigms for more lighting how semi-annual testing with two baseline tests can be a useful paradigm in clinical practice. central and peripheral vision is needed to determine 3. Anderson AJ. Significant glaucomatous visual field progression in the first their role in the current standard of care. Visual field two years: what does it mean? Trans Vis Sci Tech 2016; 5:1–11. 4. Lowry EA, Hou J, Hennein L, et al. Comparison of peristat online perimetry with testing that exploits retinal imaging technologies the humphrey perimetry in a clinic-based setting. Trans Vis Sci Tech 2016; such as fundus-tracked perimetry could improve the 5:4–14. 5. Kong YXG, He M, Crowston JG, Vingrys AJ. A comparison of perimetric precision of detecting and monitoring glaucoma- results from a tablet perimeter and humphrey field analyzer in glaucoma tous visual field loss. Such improvements could also patients. Trans Vis Sci Tech 2016; 5:2–12. 6. Johnson CA, Thapa S, George Kong YX, Robin AL. Performance of an iPad be achieved by using novel thresholding algorithms application to detect moderate and advanced visual field loss in Nepal. Am J that incorporate spatial and structural information, Ophthalmol 2017; 182:147–154. 7. Nakanishi M, Wang YT, Jung TP, et al. Detecting glaucoma with a portable and by using improved analytical techniques for && brain-computer interface for objective assessment of visual function loss. J Am detecting progression. Objective and portable devi- Med Assoc Ophthalmol 2017; 135:550–557. The study describes the development and initial validation of a portable brain- ces for assessing visual field loss offer a promising computer interface for assessing visual function loss in glaucoma. The device avenue to allow earlier and more effective detection holds promise for allowing effective home-based monitoring. 8. Anderson AJ, Bedggood PA, Kong YXG, et al. Can home monitoring allow of progression. Collectively, these new and contin- earlier detection of rapid visual field progression in glaucoma? Ophthalmology ued developments will continue to advance a chal- 2017; 124:1735–1742. 9. Yohannan J, Wang J, Brown J, et al. Evidence-based criteria for assessment of lenging, yet fundamental, test in the clinical & visual field reliability. Ophthalmology 2017; 124:1612–1620. management of glaucoma and of other eye diseases. Evidence-based guidance was provided on the interpretation of reliability indices and its impact on visual field results, highlighting their importance even in tests current considered reliable. Acknowledgements 10. Tan NYQ, Tham Y-C, Koh V, et al. The effect of testing reliability on visual field sensitivity in normal eyes. Ophthalmology 2017; doi: 10.1016/ None. j.ophtha.2017.08.002 [Epub ahead of print] 11. Rao HL, Yadav RK, Begum VU, et al. Role of visual field reliability indices in ruling out glaucoma. J Am Med Assoc Ophthalmol 2015; Financial support and sponsorship 133:40–44. 12. Ishiyama Y, Murata H, Mayama C, Asaoka R. An objective evaluation of gaze This study was supported in part by a National Institutes tracking in humphrey perimetry and the relation with the reproducibility of of Health/National Eye Institute grant EY021818 visual fields: a pilot study in glaucoma. Invest Ophthalmol Vis Sci 2014; 55:8149–8152. (F.A.M.) and National Health and Medical Research 13. Ishiyama Y, Murata H, Asaoka R. The usefulness of gaze tracking as an index Council Early Career Fellowship (#1104985, Z.W.). of visual field reliability in glaucoma patients. Invest Ophthalmol Vis Sci 2015; 56:6233–6236. F.A.M. received financial support form Alcon Labo- 14. Diniz-Filho A, Delano-Wood L, Daga FB, et al. Association between neuro- ratories (Fort Worth, Texas), Bausch & Lomb (Garden & cognitive decline and visual field variability in glaucoma. J Am Med Assoc Ophthalmol 2017; 135:734–739. City, New York), Carl Zeiss Meditec (Jena, Germany), Cognitive decline was shown to be an important determination of visual field Heidelberg Engineering (Heidelberg, Germany), Merck variability, highlighting the importance of understanding the cognitive status of a patient in the assessment of visual field progression. (White House Station, New Jersey), NGoggle, Inc. (San 15. Chew SSL, Kerr NM, Wong ABC, et al. Anxiety in visual field testing. Br J Diego, California), Allergan (Irvine, California), Sen- Ophthalmol 2016; 100:1128–1133. 16. Arai T, Murata H, Matsuura M, et al. The association between ocular surface simed (Lausanne, Switzerland), Topcon (Livermore, Cal- measurements with visual field reliability indices and gaze tracking results in ifornia), Reichert (Dewey, New York), National Eye preperimetric glaucoma. Br J Ophthalmol 2017; doi: 10.1136/bjophthalmol- 2017-310309 [Epub ahead of print] Institute (Bethesda, Maryland); research support from 17. Hood DC, Raza AS, de Moraes CGV, et al. Glaucomatous damage of the Alcon Laboratories (Fort Worth, Texas), Allergan macula. Prog Retin Eye Res 2013; 32:1–21. 18. Abe RY, Diniz-Filho A, Costa VP, et al. The impact of location of progressive (Irvine, California), Carl Zeiss Meditec (Jena, Germany), visual field loss on longitudinal changes in quality of life of patients with Reichert (Dewey, New York); consultant – Allergan glaucoma. Ophthalmology 2016; 123:552–557. 19. Sun Y, Lin C, Waisbourd M, et al. The impact of visual field clusters on (Irvine, California), Carl-Zeiss Meditec (Jena, Germany), performance-based measures and vision-related quality of life in patients with Novartis (Basel, Switzerland). glaucoma. Am J Ophthalmol 2016; 163(Suppl C):45–52.

20. Grillo LM, Wang DL, Ramachandran R, et al. The 24-2 visual field test misses 37. Chauhan BC, Johnson CA. Test-retest variability of frequency-doubling central macular damage confirmed by the 10-2 visual field test and optical perimetry and conventional perimetry in glaucoma patients and normal sub- coherence tomography. Trans Vis Sci Tech 2016; 5:15–115. jects. Invest Ophthalmol Vis Sci 1999; 40:648–656. 21. De Moraes CG, Hood DC, Thenappan A, et al. 24-2 Visual fields miss central 38. Gardiner SK, Swanson WH, Goren D, et al. Assessment of the reliability of defects shown on 10-2 tests in glaucoma suspects, ocular hypertensives, and standard automated perimetry in regions of glaucomatous damage. Ophthal- early glaucoma. Ophthalmology 2017; 124:1449–1456. mology 2014; 121:1359–1369. 22. Blumberg DM, De Moraes CG, Prager AJ, et al. Association between 39. Gardiner SK. Effect of a variability-adjusted algorithm on the efficiency of undetected 10-2 visual field damage and vision-related quality of life in perimetric testing. Invest Ophthalmol Vis Sci 2014; 55:2983. patients with glaucoma. J Am Med Assoc Ophthalmol 2017; 135:742–747. 40. Gardiner SK, Mansberger SL. Effect of restricting perimetry testing algorithms 23. Sullivan-Mee M, Karin Tran MT, Pensyl D, et al. Prevalence, features, and to reliable sensitivities on test-retest variability. Invest Ophthalmol Vis Sci && severity of glaucomatous visual field loss measured with the 10-2 achromatic 2016; 57:5631–5636. threshold visual field test. Am J Ophthalmol 2016; 168:40–51. 41. Gardiner SK, Swanson WH, Demirel S. The effect of limiting the range of The prevalence and significance of central visual field loss was revealed, although perimetric sensitivities on pointwise assessment of visual field progression in the presence of central abnormalities on the 24-2 visual field test were closely glaucoma. Invest Ophthalmol Vis Sci 2016; 57:288–294. associated with abnormalities on the 10-2 test, highlighting a need to further 42. Anderson AJ, McKendrick AM, Turpin A. Do intense perimetric stimuli saturate understand optimal methods to detect central visual field loss. the healthy visual system? Invest Ophthalmol Vis Sci 2016; 57:6397–6404. 24. Park H-YL, Hwang B-E, Shin H-Y, Park CK. Clinical clues to predict the 43. Chong LX, McKendrick AM, Ganeshrao SB, Turpin A. Customized, auto- presence of parafoveal scotoma on humphrey 10-2 visual field using a mated stimulus location choice for assessment of visual field defects. Invest Humphrey 24-2 visual field. Am J Ophthalmol 2016; 161:150–159. Ophthalmol Vis Sci 2014; 55:3265–3274. 25. LeBlanc RP, Becker B. Peripheral nasal field defects. Am J Ophthalmol 1971; 44. Chong LX, Turpin A, McKendrick AM. Assessing the GOANNA visual field 72:415–419. & algorithm using artificial scotoma generation on human observers. Trans Vis 26. Caprioli J, Spaeth GL. Static threshold examination of the peripheral nasal Sci Tech 2016; 5:1–11. visual field in glaucoma. Arch Ophthalmol 1985; 103:1150–1154. Small validation study of a visual field testing algorithm that increases the sampling 27. Mo¨ nter VM, Crabb DP, Artes PH. Reclaiming the periphery: automated kinetic density around scotoma edges to improve the spatial characterization of glauco- & perimetry for measuring peripheral visual fields in patients with glaucomaper- matous visual field loss, showing promise for future validation on a larger scale. ipheral visual fields in glaucoma. Invest Ophthalmol Vis Sci 2017; 45. Rubinstein NJ, McKendrick AM, Turpin A. Incorporating spatial models in 58:868–875. visual field test procedures. Trans Vis Sci Tech 2016; 5:7–17. An interesting study establishing a novel method for automatically quantifying the 46. Wild D, Kucur S, Sznitman R. Spatial entropy pursuit for fast and accurate peripheral visual fields, demonstrating its potential for revealing clinically important perimetry testing. Invest Ophthalmol Vis Sci 2017; 58:3414–3424. information. 47. Denniss J, McKendrick AM, Turpin A. Towards patient-tailored perimetry: 28. Odden JL, Mihailovic A, Boland MV, et al. Evaluation of central and peripheral automated perimetry can be improved by seeding procedures with patient- && visual field concordance in glaucoma. Invest Ophthalmol Vis Sci 2016; specific structural information. Trans Vis Sci Tech 2013; 2:3. 57:2797–2804. 48. Ganeshrao SB, McKendrick AM, Denniss J, Turpin A. A perimetric test An important study investigating visual field defects beyond the central 24-30 procedure that uses structural information. Optom Vis Sci 2015; 92:70–82. degrees of conventional perimetry. 49. Gardiner SK, Demirel S. Detecting change using standard global perimetric 29. Maddess T. The influence of sampling errors on test-retest variability in indices in glaucoma. Am J Ophthalmol 2017; 176:148–156. perimetry. Invest Ophthalmol Vis Sci 2011; 52:1014–1022. 50. Aoki S, Murata H, Fujino Y, et al. Investigating the usefulness of a cluster- 30. Rossetti L, Digiuni M, Rosso A, et al. Compass: clinical evaluation of a new based trend analysis to detect visual field progression in patients with open- instrument for the diagnosis of glaucoma. PLoS One 2015; 10:e0122157. angle glaucoma. Br J Ophthalmol 2017; 101:1658–1665. 31. Rao HL, Raveendran S, James V, et al. Comparing the performance of 51. Gardiner SK, Mansberger SL, Demirel S. Detection of functional change compass perimetry with humphrey field analyzer in eyes with glaucoma. J using cluster trend analysis in glaucoma. Invest Ophthalmol Vis Sci 2017; Glaucoma 2017; 26:292–297. 58:BIO180–BIO190. 32. Sato S, Hirooka K, Baba T, et al. Correlation between the ganglion cell-inner 52. Zhu H, Russell RA, Saunders LJ, et al. Detecting changes in retinal function: plexiform layer thickness measured with cirrus HD-OCT and macular visual analysis with nonstationary Weibull error regression and spatial enhancement field sensitivity measured with microperimetry. Invest Ophthalmol Vis Sci (ANSWERS). PLoS One 2014; 9:e85654. 2013; 54:3046–3051. 53. Zhu H, Crabb DP, Ho T, Garway-Heath DF. More accurate modeling of visual 33. Rao HL, Januwada M, Hussain RSM, et al. Comparing the structure-function & field progression in glaucoma: ANSWERS. Invest Ophthalmol Vis Sci 2015; relationship at the macula with standard automated perimetry and micro- 56:6077–6083. perimetry. Invest Ophthalmol Vis Sci 2015; 56:8063–8068. An improvement in the ability to detect visual field progression was achieved by 34. Hirooka K, Misaki K, Nitta E, et al. Comparison of Macular Integrity Assess- using a novel analytical technique that accounts for differing levels of measurement ment (MAIATM), MP-3, and the Humphrey field analyzer in the evaluation of the variability due to the level of visual field loss and spatial correlations. relationship between the structure and function of the macula. PLoS One 54. Warren JL, Mwanza J-C, Tanna AP, Budenz DL. A statistical model to analyze 2016; 11:e0151000. clinician expert consensus on glaucoma progression using spatially corre- 35. Wu Z, McKendrick AM, Hadoux X, et al. Test-retest variability of fundus- lated visual field data. Trans Vis Sci Tech 2016; 5:14–114. & tracked perimetry at the peripapillary region in open angle glaucoma. Invest 55. Yousefi S, Goldbaum MH, Varnousfaderani ES, et al. Detecting glaucomatous Ophthalmol Vis Sci 2016; 57:3619–3625. change in visual fields: analysis with an optimization framework. J Biomed A study showing how measurement variability in local areas of visual field damage Inform 2015; 58(Suppl C):96–103. may not be large when using fundus-tracked perimetry, highlighting the potential of 56. Yousefi S, Balasubramanian M, Goldbaum MH, et al. Unsupervised Gaussian exploiting retinal imaging during visual field testing. mixture-model with expectation maximization for detecting glaucomatous 36. Heijl A, Lindgren A, Lindgren G. Test-retest variability in glaucomatous visual progression in standard automated perimetry visual fields. Trans Vis Sci Tech fields. Am J Ophthalmol 1989; 108:130–135. 2016; 5:2.