Glaucoma Rehabilitation Using ElectricAI Transcranial Stimulation (GREAT)-Optimizing Stimulation Protocol for Vision Enhancement Using an RCT.

Purpose: We compared the effect of three different transcranial electrical stimulation (tES) protocols delivered to the occipital lobe on peripheral vision in patients with glaucoma. Methods: A double-masked, placebo-controlled study was conducted with 35 patients with glaucoma. We compared three different tES protocols: anodal transcranial direct current stimulation (a-tDCS), transcranial alternating current stimulation (tACS), and transcranial random noise stimulation (tRNS) against sham stimulation. Each patient attended four stimulation sessions (a-tDCS, tACS, tRNS, and sham) in a random order with at least 48 hours between visits. Stimulation involved placing an anodal electrode over the occipital lobe (Oz) and cathodal electrode on the cheek for 20 minutes. High-resolution perimetry (HRP) and multifocal visual evoked potential (mfVEP) measurements were made before and immediately after stimulation. Changes in HRP detection accuracy/reaction time and mfVEP signal-to-noise ratio (SNR)/latency were analyzed using linear mixed models. Results: Compared to sham, HRP detection accuracy was significantly improved after a-tDCS in both the central 20-degree (b = 0.032, P = 0.018) and peripheral analysis (b = 0.051, P = 0.002). Additionally, mfVEP SNR was significantly increased (b = 0.016, P = 0.017) and the latency was shortened (b = -1.405, P = 0.04) by the a-tDCS in the central 20-degree analysis. In the peripheral analysis, there was a trend toward an enhancement of SNR after a-tDCS stimulation (b = 0.014, P = 0.052), but it did not reach statistical significance; latency was increased after tACS (b = 1.623, P = 0.041). No significant effects were found in comparison to other active tES protocols. Conclusions: A single session of a-tDCS enhances perceptual and electrophysiologic measures of vision in patients with glaucoma. However, the small magnitude of changes observed in HRP (3.2% for accuracy in central and 5.1% in peripheral) did not exceed previous test variability and may not be clinically meaningful. Translational Relevance: a-tDCS holds promise as a potential treatment for enhancing visual function. However, future studies are needed to evaluate the long-term effects and clinical relevance of this intervention using validated measures of perimetric changes in the visual field.

Fuzzy clustering of 24-2 visual field patterns can detect glaucoma progression.

PURPOSE: To represent 24-2 visual field (VF) losses of individual patients using a hybrid approach of archetypal analysis (AA) and fuzzy c-means (FCM) clustering. METHODS: In this multicenter retrospective study, we classified characteristic patterns of 24-2 VF using AA and decomposed them with FCM clustering. We predicted the change in mean deviation (MD) through supervised machine learning from decomposition coefficient change. In addition, we compared the areas under the receiver operating characteristic curves (AUCs) of the decomposition coefficient slopes to detect VF progression using three criteria: MD slope, Visual Field Index slope, and pointwise linear regression analysis. RESULTS: We identified 16 characteristic patterns (archetypes or ATs) of 24-2 VF from 132,938 VFs of 18,033 participants using AA. The hybrid approach using FCM revealed a lower mean squared error and greater correlation coefficient than the AA single approach for predicting MD change (all P ≤ 0.001). Three of 16 AUCs of the FCM decomposition coefficient slopes outperformed the AA decomposition coefficient slopes in detecting VF progression for all three criteria (AT5, superior altitudinal defect; AT10, double arcuate defect; AT13, total loss) (all P ≤ 0.028). CONCLUSION: A hybrid approach combining AA and FCM to analyze 24-2 VF can visualize VF tests in characteristic patterns and enhance detection of VF progression with lossless decomposition.

The assessment of structural and functional test results for early detection of hydroxychloroquine macular toxicity.

PURPOSE: To assess structural (optical coherence tomography, fundus autofluorescence) and functional (contrast sensitivity and visual field) test results which were used for detecting early retinal changes in patients using oral hydroxychloroquine. METHODS: Patients using oral hydroxychloroquine for at least one year were divided into two groups according to the duration of drug use. Groups 1 and 2 consisted of patients with drug use for more than 5 years and 1-5 years, respectively. The drug-using groups were compared with the control group. The mean retinal nerve fiber layer (RNFL), central macular thickness (CMT), ganglion cell-inner plexiform layer (GC-IPL), static 10-2 visual field, fundus autofluorescence (FAF) imaging, and contrast sensitivity tests were performed and statistically compared between groups. RESULTS: Median and temporal quadrant RNFL thicknesses were found to be statistically significantly lower in the drug groups. In the drug groups, the GC-IPL sectoral and mean thicknesses were found to be statistically lower in all quadrants. Central macular thickness was also found to be similar in all three groups. There was no significant difference between the groups in visual field parameters. Macular FAF images were significantly higher in the drug users, but there was no significant difference between the three groups in foveal FAF images. Contrast sensitivity measurements were significantly lower in the drug groups than in the control group at all spatial frequencies except 6 and 18 cycles/degree. CONCLUSIONS: The combined use of structural and functional tests in patients using hydroxychloroquine provides useful information in detecting early retinal changes.

Long-Term Rate of Optic Disc Rim Loss in Glaucoma Patients Measured From Optic Disc Photographs With a Deep Neural Network.

Purpose: This study uses deep neural network-generated rim-to-disc area ratio (RADAR) measurements and the disc damage likelihood scale (DDLS) to measure the rate of optic disc rim loss in a large cohort of glaucoma patients. Methods: A deep neural network was used to calculate RADAR and DDLS for each optic disc photograph (ODP). Patient demographics, diagnosis, intraocular pressure (IOP), and mean deviation (MD) from perimetry were analyzed as risk factors for faster progression of RADAR. Receiver operating characteristic (ROC) curves were used to compare RADAR and DDLS in their utility to distinguish glaucoma from glaucoma suspect (GS) and for detecting glaucoma progression. Results: A total of 13,679 ODPs with evidence of glaucomatous optic nerve damage from 4106 eyes of 2407 patients with glaucoma or GS were included. Of these eyes, 3264 (79.5%) had a diagnosis of glaucoma, and 842 (20.5%) eyes were GS. Mean ± SD baseline RADAR of GS and glaucoma were 0.67 ± 0.13 and 0.57 ± 0.18, respectively (P < 0.001). Older age, greater IOP fluctuation, baseline MD, right eye, and diagnosis of secondary open-angle glaucoma were associated with slope of RADAR. The mean baseline DDLS of GS and glaucoma were 3.78 and 4.39, respectively. Both RADAR and DDLS showed a less steep slope in advanced glaucoma. In glaucoma, the change of RADAR and DDLS correlated with the corresponding change in MD. RADAR and DDLS had a similar ability to discriminate glaucoma from GS and detect disease progression. Area under the ROC curve of RADAR and DDLS was 0.658 and 0.648. Conclusions: Automated calculation of RADAR and DDLS with a neural network can be used to evaluate the extent and long-term rate of optic disc rim loss and is further evidence of long-term nerve fiber loss in treated patients with glaucoma. Translational Relevance: Our study provides a large clinic-based experience for RADAR and DDLS measurements in GS and glaucoma with a neural network.

Assessing Visual Crowding in Participants With Preperimetric Glaucoma Using Eye Movement and Manual Response Paradigms.

Purpose: Crowding is the inability to distinguish objects in the periphery in the presence of clutter. Previous studies showed that crowding is elevated in patients with glaucoma. This could serve as an indicator of the functional visual performance of patients with glaucoma but at present appears too time-consuming and attentionally demanding. We examined visual crowding in individuals with preperimetric glaucoma to compare the potential effectiveness of eye movement-based and manual response paradigms. Methods: We assessed crowding magnitude in 10 participants with preperimetric glaucoma and 10 age-matched controls. Crowding magnitudes were assessed using four different paradigms: a conventional two-alternative forced choice (2AFC) manual, a 2AFC and a six-alternative forced choice (6AFC) eye movement, and a serial search paradigm. All paradigms measured crowding magnitude by comparing participants' orientation discrimination thresholds in isolated and flanked stimulus conditions. Moreover, assessment times and participant preferences were compared across paradigms. Results: Patients with preperimetric glaucoma exhibited elevated crowding, which was most evident in the manual-response paradigm. The serial search paradigm emerged as the fastest method for assessing thresholds, yet it could not effectively distinguish between glaucoma and control groups. The 6AFC paradigm proved challenging for both groups. Conclusions: We conclude that patients with preperimetric glaucoma demonstrate heightened binocular visual crowding. This is most effectively demonstrated via the 2AFC manual response paradigm. The additional attentional demand in eye movement paradigms rendered them less effective in the elderly population of the present study. Translational Relevance: Our findings underscore both the value and the complexity of efficiently evaluating crowding in elderly participants, including those with preperimetric glaucoma.

Bidirectional gated recurrent unit network model can generate future visual field with variable number of input elements.

PURPOSE: This study aimed to predict future visual field tests using a bidirectional gated recurrent unit (Bi-GRU) and assess its performance based on the number of input visual field tests and the prediction time interval. MATERIALS AND METHODS: This study included patients who underwent visual field tests at least four times at five university hospitals between June 2004 and April 2022. All data were accessed in October 2022 for research purposes. In total, 23,517 eyes with 185,858 visual field tests were used as the training dataset, and 1,053 eyes with 9,459 visual field tests were used as the test dataset. The Bi-GRU architecture was designed to take a variable number of visual field tests, ranging from 3 to 80, as input and predict visual field tests at the desired arbitrary time point. It generated the mean deviation (MD), pattern standard deviation (PSD), Visual Field Index (VFI), and total deviation value (TDV) for 54 test points. To analyze the model performance, the mean absolute error between the actual and predicted values was calculated and analyzed for glaucoma severity, number of input visual field tests, and prediction time interval. RESULTS: The prediction errors of the Bi-GRU model for MD, PSD, VFI, and TDV ranged from 1.20 to 1.68 dB, 0.95 to 1.16 dB, 3.64 to 4.51%, and 2.13 to 2.60 dB, respectively, depending on the number of input visual field tests. Prediction errors tended to increase as the prediction time interval increased; however, the difference was not statistically significant. As the severity of glaucoma worsened, the prediction errors significantly increased. CONCLUSION: In clinical practice, the Bi-GRU model can predict future visual field tests at the desired time points using three or more previous visual field tests.

Comparison of Glaucoma Detection Performance of Binocular Perimetry Screening Program Using imo Perimetry With Frequency Doubling Technology.

Purpose: We aimed to preliminarily compare the glaucoma detection accuracy of a head-mounted binocular visual perimeter "imo" screening program (ISP) with that of frequency doubling technology (FDT). Methods: This multicenter, diagnostic accuracy study based on prospectively collected data included 76 non-glaucoma (including pre-perimetric glaucoma) eyes and 92 glaucomatous eyes from patients visiting two hospitals. Patients underwent ISP and FDT (C-20-1 screening program) on the same day. Diagnostic efficacy was evaluated using receiver operating characteristic curves and areas under the curve (AUCs). In addition, we compared the ISP and FDT testing times. Results: AUC values for ISP versus FDT were as follows: (1) mild-stage glaucoma (mean deviation [MD] > -6 dB), 0.82 (95% confidence interval [CI], 0.75-0.88) versus 0.76 (95% CI, 0.68-0.83); moderate-stage glaucoma (-6 dB ≥ MD ≥ -12 dB), 0.98 (95% CI, 0.95-1.00) versus 0.96 (95% CI, 0.93-1.00); and advanced-stage glaucoma (-12 dB > MD), 1.00 (95% CI, 1.00-1.00) versus 0.99 (95% CI, 0.98-1.00). In addition, mild-stage glaucoma was classified into two stages (MD > -3 D) and (-3 D ≥ MD > -6 D). AUC values were 0.81 (95% CI, 0.73-0.88) versus 0.76 (95% CI, 0.68-0.84) for MD > -3 D and 0.86 (95% CI, 0.77-0.94) versus 0.73 (95% CI, 0.61-0.86) for -3 D ≥ MD > -6 D. The testing time for the ISP was significantly shorter than that of FDT for all glaucoma stages (P < 0.001). Conclusions: The ISP demonstrates non-inferiority in detecting glaucoma and has a shorter testing time compared with FDT. These findings provide evidence for applied further studies on large-scale population-based glaucoma screening. Translational Relevance: Our study provides a non-inferior and quicker glaucoma screening than existing tools.

Glaucoma Home Self-Testing Using VR Visual Fields and Rebound Tonometry Versus In-Clinic Perimetry and Goldmann Applanation Tonometry: A Pilot Study.

Purpose: This pilot study aimed to assess the feasibility, accuracy, and repeatability of unsupervised, at-home, multi-day glaucoma testing using the Olleyes VisuALL Virtual Reality Platform (VRP) and the iCare HOME handheld self-tonometer. Methods: Participants were trained to use two U.S. Food and Drug Administration-registered or approved devices before conducting self-tests at home over 3 consecutive days. The iCare HOME intraocular pressure (IOP) measurements were collected four times daily per eye, and VRP visual field tests were performed once daily. The results were compared with one in-clinic Humphrey Field Analyzer (HFA) visual field test performed on the day of device training, iCare HOME measurements by the trainer, and the last five Goldmann applanation tonometer (GAT) results. Results: Of 15 enrolled participants, nine of them (60%) completed the study. The six excluded participants could not self-measure using iCare HOME. There was significant correlation between the average mean deviation (MD) values of the at-home VRP tests and in-clinic HFA test (r2 = 0.8793, P < 0.001). Additionally, the average of the sensitivities in five of six Garway-Heath sectors were significantly correlated. VRP test duration was also shorter than in-clinic HFA testing (P < 0.001). Finally, at-home tonometry yielded statistically similar values compared to trainer-obtained iCare HOME values. The mean and range of at-home tonometry were also statistically similar to those for in-clinic GAT, but at-home tonometry demonstrated higher maximum IOP values (P = 0.0429). Conclusions: Unsupervised, at-home, multi-day glaucoma testing using two devices resulted in the capture of higher maximum IOPs than in the clinic and good MD correlation of VRP with HFA. However, 40% of participants could not self-measure IOP using iCare HOME. Translational Relevance: The study findings suggest that at-home remote glaucoma monitoring correlates with in-office testing and could provide additional information for glaucoma management, although patients had more difficulty with the iCare HOME than the VRP.

Transformer-Based Deep Learning Prediction of 10-Degree Humphrey Visual Field Tests From 24-Degree Data.

Purpose: To predict 10-2 Humphrey visual fields (VFs) from 24-2 VFs and associated non-total deviation features using deep learning. Methods: We included 5189 reliable 24-2 and 10-2 VF pairs from 2236 patients, and 28,409 reliable pairs of macular OCT scans and 24-2 VF from 19,527 eyes of 11,560 patients. We developed a transformer-based deep learning model using 52 total deviation values and nine VF test features to predict 68 10-2 total deviation values. The mean absolute error, root mean square error, and the R2 were evaluation metrics. We further evaluated whether the predicted 10-2 VFs can improve the structure-function relationship between macular thinning and paracentral VF loss in glaucoma. Results: The average mean absolute error and R2 for 68 10-2 VF test points were 3.30 ± 0.52 dB and 0.70 ± 0.11, respectively. The accuracy was lower in the inferior temporal region. The model placed greater emphasis on 24-2 VF points near the central fixation point when predicting the 10-2 VFs. The inclusion of nine VF test features improved the mean absolute error and R2 up to 0.17 ± 0.06 dB and 0.01 ± 0.01, respectively. Age was the most important 24-2 VF test parameter for 10-2 VF prediction. The predicted 10-2 VFs achieved an improved structure-function relationship between macular thinning and paracentral VF loss, with the R2 at the central 4, 12, and 16 locations of 24-2 VFs increased by 0.04, 0.05 and 0.05, respectively (P < 0.001). Conclusions: The 10-2 VFs may be predicted from 24-2 data. Translational Relevance: The predicted 10-2 VF has the potential to improve glaucoma diagnosis.

Multimodal High-Resolution Imaging in Retinitis Pigmentosa: A Comparison Between Optoretinography, Cone Density, and Visual Sensitivity.

Purpose: Retinitis pigmentosa (RP), the most common inherited retinal disease, is characterized by progressive photoreceptor degeneration. It remains unknown to what extent surviving photoreceptors transduce light and support vision in RP. To address this, we correlated structure and functional measures using adaptive optics scanning laser ophthalmoscopy (AOSLO), adaptive optics microperimetry, and adaptive optics optical coherence tomography (AO-OCT)-based optoretinograms (ORGs). Methods: Four patients with RP were imaged with AOSLO across the visual field covering the transition zone (TZ) of normal to diseased retina. Cone density was estimated in discrete regions spanning the TZ. Visual sensitivity was assessed by measuring increment thresholds for a 3-arcmin stimulus targeted via active eye tracking in AOSLO. ORGs were measured at the same locations using AO-OCT to assess the cones' functional response to a 528 ± 20-nm stimulus. Individual cone outer segment (COS) lengths were measured from AO-OCT in each subject. Results: Cone density was significantly reduced in patients with RP. Density reduction correlated with TZ location in 3 patients with RP, while a fourth had patches of reduced density throughout the retina. ORG amplitude was reduced in regions of normal and reduced cone density in all patients with RP. ORG response and COS length were positively correlated in controls but not in patients with RP. Despite deficits in cone density and ORG, visual sensitivity remained comparable to controls in three of four patients with RP. Conclusions: ORG-based measures of retinal dysfunction may precede deficits in cone structure and visual sensitivity. ORG is a sensitive measure of RP disease status and has significant potential to provide insight into disease progression and treatment efficacy.

TORONTO: A trial-oriented multidimensional psychometric testing algorithm.

Bayesian adaptive methods for sensory threshold determination were conceived originally to track a single threshold. When applied to the testing of vision, they do not exploit the spatial patterns that underlie thresholds at different locations in the visual field. Exploiting these patterns has been recognized as key to further improving visual field test efficiency. We present a new approach (TORONTO) that outperforms other existing methods in terms of speed and accuracy. TORONTO generalizes the QUEST/ZEST algorithm to estimate simultaneously multiple thresholds. After each trial, without waiting for a fully determined threshold, the trial-oriented approach updates not only the location currently tested but also all other locations based on patterns in a reference data set. Since the availability of reference data can be limited, techniques are developed to overcome this limitation. TORONTO was evaluated using computer-simulated visual field tests: In the reliable condition (false positive [FP] = false negative [FN] = 3%), the median termination and root mean square error (RMSE) of TORONTO was 153 trials and 2.0 dB, twice as fast with equal accuracy as ZEST. In the FP = FN = 15% condition, TORONTO terminated in 151 trials and was 2.2 times faster than ZEST with better RMSE (2.6 vs. 3.7 dB). In the FP = FN = 30% condition, TORONTO achieved 4.2 dB RMSE in 148 trials, while all other techniques had > 6.5 dB RMSE and terminated much slower. In conclusion, TORONTO is a fast and accurate algorithm for determining multiple thresholds under a wide range of reliability and subject conditions.

Assessment of local sensitivity in incomplete retinal pigment epithelium and outer retinal atrophy (iRORA) lesions in intermediate age-related macular degeneration (iAMD).

Lesions of incomplete retinal pigment epithelium and outer retinal atrophy (iRORA) are associated with disease progression in age-related macular degeneration. However, the corresponding functional impact of these precursor lesions is unknown.We present a cross-sectional study of four patients employing clinical-grade MAIA (stimulus size: 0.43°, ~125 µm) and adaptive optics scanning light ophthalmoscope (AOSLO, stimulus size 0.07°, ~20 µm) based microperimetry (MP) to assess the specific impact of iRORA lesions on retinal sensitivity.AOSLO imaging showed overall reduced photoreceptor reflectivity and patches of hyporeflective regions at drusen with interspersed hyper-reflective foci in iRORA regions. MAIA-MP yielded an average retinal sensitivity loss of -7.3±3.1 dB at iRORA lesions compared with the in-eye control. With AOSLO-MP, the corresponding sensitivity loss was 20.1±4.8 dB.We demonstrated that iRORA lesions are associated with a severe impairment in retinal sensitivity. Larger cohort studies will be necessary to validate our findings.

Use of the perceptual point-spread function to assess dysphotopsias.

Nowadays many patients are choosing EDOF or multifocal lenses for replacement of natural lens in cataract surgery. This can result in issues such as presence of dysphotopsias, namely halo and glare. In this work, we propose a new perimetry method to describe dysphotopsias in far-field region in a presence of bright, point-like light source. We constructed a custom device and designed measurement procedure for quantitative measurement of dysphotopias in the center of visual field and used it to examine patients with mild cataracts or implanted IOLs. Our approach may help in establishing an objective method to study and compare dysphotopsias.

Retinal Ganglion Cell Content Underlying Standard Automated Perimetry Size I to V Visual Sensitivities in the Non-Human Primate Experimental Glaucoma Model.

Purpose: To determine the relationship between visual sensitivities from white-on-white Goldmann size I to V stimuli and the underlying retinal ganglion cell (RGC) content in the non-human primate (NHP) experimental glaucoma model. Methods: Normative data were collected from 13 NHPs. Unilateral experimental glaucoma was induced in seven animals with the least variable fields who were monitored using optical coherence tomography and 30-2 full-threshold standard automated perimetry (SAP). At varying endpoints, animals were euthanized followed by perfusion fixation, and 1-mm retinal punches were obtained from 34 corresponding SAP locations. RGCs were immunolabeled with an antibody against an RNA-binding protein (RBPMS) marker and imaged using confocal microscopy. RGC counts from each location were then related to visual sensitivities for each stimulus size, after accounting for ocular magnification. Results: At the endpoint, the circumpapillary retinal nerve fiber layer thickness for experimental glaucoma eyes ranged from 47 to 113 µm. RGC density in control eyes was greatest for the 4.24° sample (18,024 ± 6869 cells/mm2) and decreased with eccentricity. Visual sensitivity at each tested location followed that predicted by spatial summation, with the critical area increasing with eccentricity (slope = 0.0036, R2 = 0.44). The relationship between RGC counts and visual sensitivity was described using a two-line fit, where the intercept of the first segment and hinge points were dependent on eccentricity. Conclusions: In NHPs, SAP visual thresholds are related to the underlying RGCs. The resulting spatial summation based structure-function model can be used to estimate RGC content from any standard white-on-white stimulus size.

Investigating the impact of asymmetric macular sensitivity on visual acuity chart reading in choroideremia.

INTRODUCTION: Degeneration in choroideremia, unlike typical centripetal photoreceptor degenerations, is centred temporal to the fovea. Once the fovea is affected, the nasal visual field (temporal retina) is relatively spared, and the preferred retinal locus shifts temporally. Therefore, when reading left to right, only the right eye reads into a scotoma. We investigate how this unique property affects the ability to read an eye chart. METHODS: Standard- and low-luminance visual acuity (VA) for right and left eyes were measured with the Early Treatment of Diabetic Retinopathy Study (ETDRS) chart. Letters in each line were labelled by column position. The numbers of letter errors for each position across the whole chart were summed to produce total column error scores for each participant. Macular sensitivity was assessed using microperimetry. Central sensitivity asymmetry was determined by the temporal-versus-nasal central macular difference and subsequently correlated to a weighted ETDRS column error score. Healthy volunteers and participants with X-linked retinitis pigmentosa GTPase regulator associated retinitis pigmentosa (RPGR-RP) were used as controls. RESULTS: Thirty-nine choroideremia participants (median age 44.9 years [IQR 35.7-53.5]), 23 RPGR-RP participants (median age 30.8 years [IQR 26.5-40.5]) and 35 healthy controls (median age 23.8 years [IQR 20.3-29.0]) were examined. In choroideremia, standard VA in the right eye showed significantly greater ETDRS column errors on the temporal side compared with the nasal side (p = 0.002). This significantly correlated with greater asymmetry in temporal-versus-nasal central macular sensitivity (p = 0.04). No significant patterns in ETDRS column errors or central macular sensitivity were seen in the choroideremia left eyes, nor in RPGR-RP and control eyes. CONCLUSION: Difficulty in tracking across lines during ETDRS VA testing may cause excess errors independent of true VA. VA assessment with single-letter optotype systems may be more suitable, particularly for patients with choroideremia, and potentially other retinal diseases with asymmetric central macular sensitivity or large central scotomas including geographic atrophy.

Microperimetry Characteristics of Regions With a Truly Nonresponding Location: Implications for Atrophic Age-Related Macular Degeneration.

Purpose: To understand the microperimetry response characteristics of regions with a truly nonresponding location, which will be useful when considering criteria for end-stage atrophic age-related macular degeneration (AMD). Methods: A simulation model was developed using data from 128 participants with bilateral large drusen at baseline seen over 36 months at 6-month intervals. One hundred thousand pairs of real-world microperimetry testing results were simulated separately with and without one truly nonresponding location, where the sensitivity of one randomly selected location for the former group was derived from the distribution of responses from a truly nonresponding location at the optic nerve head from 60 healthy participants. Results: Only 60% of the simulated test pairs with a truly nonresponding location had ≥1 location that was <0 decibel (dB) on both tests. In contrast, 91% of the simulated test pairs had ≥1 location that was ≤10 dB on both tests, and 87% had ≥1 location that was ≤10 dB on both tests and <0 dB for one of the tests. Of the simulated test pairs without a truly nonresponding location, there were 0.04%, 1.4%, and 0.4% that met these three above criteria, respectively. Conclusions: Regions with a truly nonresponding test location do not almost always show a repeatable absolute scotoma (<0 dB), but instead, much more often a deep visual sensitivity defect (≤10 dB), with or without having an absolute scotoma on one of the tests. These findings are crucial if functional criteria are to be considered as part of a definition of end-stage atrophic AMD.

Impact and visualization of scotomatic glare in central visual field perception.

Strong monochromatic point light sources such as Light Emitting Diodes (LED) or Lasers have been increasingly used in recent decades. This also raises the risk of misuse resulting in glare phenomena and associated visual impairment. The objective of this prospective and partially blinded study was the visualization and characterization of glare-induced scotomas in visual field by dazzling with monochromatic point light sources in terms of disability and discomfort glare. Automated threshold perimetry under dazzling by LED exposure at three different wavelengths (470, 530 and 625 nm) and four different intensities (25, 50, 75, and 100%) was performed in 31 healthy subjects resulting in 434 visual field examinations. Visual disability was measured by sensitivity loss in the central 30°as compared to unexposed controls and visualized by reconstruction of mean visual fields for each group via backward-calculation. Psychological glare was assessed by subsequent questionnaire and evaluated based on the de Boer rating scale of discomfort. Increasing glare intensities resulted in a significant decrease in mean sensitivity for all wavelengths tested, paralleled by an increase of discomfort glare. The loss of sensitivity was scattered over all quadrants with accentuation of the corresponding mean exposure area. Reconstructed visual fields confirmed visual impairment in all quadrants at an extent of at least 30°. We conclude that even off-axis light exposure may affect central visual field perception. Our results extend previous research on directed light interaction and contribute in explaining its incapacitating impact on human performance.