Comparison of Contrast Sensitivity, Visual Acuity, and Humphrey Visual Field Testing in Patients with Glaucoma:

Association between contrast sensitivity function and structural damage in primary open-angle glaucoma

AIMS

To evaluate the association between contrast sensitivity function (CSF) and glaucomatous structural damage in primary open-angle glaucoma (POAG).

METHODS

A cross-sectional study was performed with 103 patients (103 eyes) aged 25-50 years who had POAG without any other ocular disease. CSF measurements were obtained by the quick CSF method, a novel active learning algorithm that covers 19 spatial frequencies and 128 contrast levels. The peripapillary retinal nerve fibre layer (pRNFL), macular ganglion cell complex (mGCC), radial peripapillary capillary (RPC) and macular vasculature were measured by optical coherence tomography and angiography. Correlation and regression analyses were used to assess the association of area under log CSF (AULCSF), CSF acuity and contrast sensitivities at multiple spatial frequencies with structural parameters.

RESULTS

AULCSF and CSF acuity were positively associated with pRNFL thickness, RPC density, mGCC thickness and superficial macular vessel density (p<0.05). Those parameters were also significantly associated with contrast sensitivity at 1, 1.5, 3, 6, 12, 18 cycles per degree spatial frequencies (p<0.05) and, the lower the spatial frequency, the higher the correlation coefficient. RPC density (p=0.035, p=0.023) and mGCC thickness (p=0.002, p=0.011) had significant predictive value for contrast sensitivity at 1 and 1.5 cycles per degree, with adjusted R 2 of 0.346 and 0.343, respectively.

CONCLUSIONS

Full spatial frequency contrast sensitivity impairment, most notably at low spatial frequencies, is a characteristic change in POAG. Contrast sensitivity is a potential functional endpoint for the measurement of glaucoma severity.

Extraction of three-dimensional shapes in glaucoma patients in response to monocular depth cues

PURPOSE

To assess the impact of glaucoma on perceiving three-dimensional (3D) shapes based on monocular depth cues.

STUDY DESIGN

Clinical observational study.

METHODS

Twenty glaucoma patients, subjected to binocular visual-field sensitivity (binocular-VFS) tests using a Humphrey Visual Field Analyzer, and 20 age-matched healthy volunteers, underwent two tasks: identifying the nearest vertex of a 3D shape using monocular shading (3D-SfS), texture (3D-SfT), or motion (3D-SfM) cues, and distinguishing elementary one-dimensional (1D) features of these cues. The association of the visual-field index (VFI) of binocular-VFS with 3D shape perception in glaucoma patients was also examined.

RESULTS

Glaucoma patients demonstrated reduced accuracy in distinguishing 1D luminance brightness and a larger "error-in-depth" between the perceived and actual depths for 3D-SfM and 3D-SfS compared to healthy volunteers. Six glaucoma patients with a 100% VFI for binocular-VFS exhibited a similar error-in-depth to the other fourteen glaucoma patients; they had a larger error-in-depth for 3D-SfM compared to healthy volunteers. No correlation between the error-in-depth values and the VFI values of binocular-VFS was observed.

CONCLUSIONS

The 3D shape perception in glaucoma patients varies based on the depth cue's characteristics. Impaired 1D discrimination and larger thresholds for 3D-SfM in glaucoma patients with a 100% VFI for binocular-VFS indicate more pronounced perceptual deficits of lower-level elementary features for 3D-SfS and higher-level visual processing of 3D shapes for 3D-SfM. The effects of the location and degree of binocular visual-field defects on 3D shape perception remain to be elucidated. Our research provides insights into the 3D shape extraction mechanism in glaucoma.

Association of Contrast Sensitivity With Eye Disease and Vision-Related Quality of Life

PURPOSE

To investigate contrast sensitivity (CS) as a screening tool to detect eye disease and assess its association with both eye disease and vision-related quality of life.

DESIGN

Cross-sectional study.

METHODS

Setting and population: Adults receiving care from a free clinic and a Federally Qualified Health Center in Michigan.

MAIN OUTCOME MEASURES

Screening positive for eye disease and Visual Function Questionnaire (VFQ) score.

OBSERVATION

Participants received a vision exam reviewed via telemedicine for disease, completed a demographic survey, and the 9-item VFQ. The ability of CS to predict eye disease was explored and area under the curve (AUC) is reported. Logistic and linear regression were used to investigate the continuous effect of CS on the probability of screening positive for eye disease and VFQ score, respectively, adjusting for age and visual acuity.

RESULTS

1159 included participants were, on average, 54.9 ± 14.5 years old, 62% identified as female, 34% as White, 54% as Black, 10% as Hispanic/Latino, and reported mean VFQ score of 79.7 ± 15.3. CS ranged from 0.00 to 1.95 log units (mean = 1.54 ± 0.24), 21% of eyes had glaucoma, 19% cataract, 6% DR, and 2% AMD. AUCs were 0.53 to 0.73. A 0.3 log unit decrease in better eye CS was associated with increased odds of glaucoma (odds ratio [OR] = 1.35, confidence interval [CI] = 1.09-1.67), cataract (OR = 1.35, CI = 1.05-1.72), DR (OR = 2.05, CI = 1.51-2.77), and AMD (OR = 2.08, CI = 1.10-3.91). A 0.3 log unit increase in better eye CS was associated with a 5.9 unit increase in VFQ.

CONCLUSION

While CS alone is not sufficient to identify people with eye disease, it is an important measure of visual function that can add value to comprehensive eye screening.

Effect of presbyopic correction lens on humphrey visual field testing in patients with multifocal intraocular lens

Most previous studies on the effects of multifocal intraocular lenses (MIOL) on Humphrey visual field (HVF) used presbyopic corrective lens (PC). There has been insufficient data from patients with MIOL performing HVF with and without PC. This study aimed to determine the effect of PC on HVF testing in patients with MIOL. This was a prospective, comparative crossover study at the Department of Ophthalmology, Faculty of Medicine, Siriraj Hospital, Mahidol University between June 2015 and July 2018. Early-stage glaucomatous and non-glaucomatous pseudophakic patients with 2 models of MIOL completed HVF testing with and without PC. Mean deviation (MD), pattern standard deviation (PSD), and reliability indices (fixation losses, false positives, and false negatives) were compared. Ninety-four eyes of 59 patients were enrolled. After excluding patients with confirmed unreliable visual field, 82 eyes of 51 patients (male, 22; female, 29) with a mean age of 65.4 years were included in the study. Forty-nine eyes were non-glaucoma and 33 eyes were early-stage glaucoma. Forty-four eyes received TECNIS ZM900 and 38 eyes received Acrysof IQ ReSTOR SN6AD1. The overall MD standard deviation was -3.5 (2.1) with PC and -3.1 (2.1) without PC (P = .01). The overall PSD standard deviation was 2.8 (1.5) with PC and 2.7 (1.5) without PC (P = .93). The reliability indices were not statistically significantly different with and without PC. There was a good intraclass correlation (ICC) of MD (ICC = 0.87) and PSD (ICC = 0.88) with and without PC. Eyes with TECNIS ZM 900 had significantly better MD when performing HVF without PC (mean difference -0.7, P < .01), but not with Acrysof IQ ReSTOR SN6AD1 (mean difference -0.1, P = .74). Pseudophakic eyes with MIOL may not require PC during HVF testing regardless of the MIOL model. Although eyes with TECNIS ZM900 performed HVF without PC resulted in a significantly better MD value compared with PC, the difference was not clinically significant.

Comparison of the Visual Outcomes of Enhanced and Standard Monofocal Intraocular Lens Implantations in Eyes with Early Glaucoma

This study aimed to compare the efficacies and safety of enhanced and standard monofocal intraocular lenses (IOLs) in eyes with early glaucoma. Patients with concurrent cataracts and open-angle glaucoma (OAG) were enrolled. They underwent cataract surgery with IOL implantation. The comprehensive preoperative ophthalmic examination included the manifest refraction; monocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), and uncorrected near visual acuity (UNVA); visual field (VF); and contrast sensitivity (CS); defocus curves and questionnaires were assessed three months postoperatively. Totals of 34 and 38 patients had enhanced and standard monofocal IOLs, respectively. The enhanced monofocal IOL provided better UIVA than the standard monofocal IOL (p = 0.003) but similar UDVA, CDVA, and UNVA. The enhanced monofocal IOL had more consistent defocus curves than the standard monofocal IOL, especially at -1 (p = 0.042) and -1.5 (p = 0.026) diopters. The enhanced monofocal IOL provided better satisfaction (p = 0.019) and lower spectacle dependence (p = 0.004) than the standard monofocal IOL for intermediate vision, with similar VF and CS outcomes. In conclusion, enhanced monofocal IOLs are recommended for patients with OAG because they provide better intermediate vision, higher satisfaction, and lower dependence on spectacles than standard monofocal IOLs, without worsening other visual outcomes.

Premium Intraocular Lenses in Glaucoma-A Systematic Review

The incidence of both cataract and glaucoma is increasing globally. With increasing patient expectation and improved technology, premium intraocular lenses (IOLs), including presbyopia-correcting and toric IOLs, are being increasingly implanted today. However, concerns remain regarding the use of premium IOLs, particularly presbyopia-correcting IOLs, in eyes with glaucoma. This systematic review evaluates the use of premium IOLs in glaucoma. A comprehensive search of the MEDLINE database was performed from inception until 1 June 2023. Initial search yielded 1404 records, of which 12 were included in the final review of post-operative outcomes. Studies demonstrated high spectacle independence for distance and good patient satisfaction in glaucomatous eyes, with positive outcomes also in post-operative visual acuity, residual astigmatism, and contrast sensitivity. Considerations in patient selection include anatomical and functional factors, such as the type and severity of glaucomatous visual field defects, glaucoma subtype, presence of ocular surface disease, ocular changes after glaucoma surgery, and the reliability of disease monitoring, all of which may be affected by, or influence, the outcomes of premium IOL implantation in glaucoma patients. Regular reviews on this topic are needed in order to keep up with the rapid advancements in IOL technology and glaucoma surgical treatments.

Five-Year Visual Field Outcomes of the HORIZON Trial

PURPOSE

To compare visual field (VF) progression between glaucoma patients receiving cataract surgery alone (CS) or with a Hydrus microstent (CS-HMS).

DESIGN

Post hoc analysis of VF data from the HORIZON multicenter randomized controlled trial.

METHODS

A total of 556 patients with glaucoma and cataract were randomized 2:1 to either CS-HMS (369) or CS (187) and followed up for 5 years. VF was performed at 6 months and then every year after surgery. We analyzed data for all participants with at least 3 reliable VFs (false positives < 15%). Average between-group difference in rate of progression (RoP) was tested using a Bayesian mixed model and a 2-sided Bayesian P value <.05 (main outcome). A multivariable model measured the effect of intraocular pressure (IOP). A survival analysis compared the probability of global VF sensitivity dropping by predefined cutoffs (2.5, 3.5, 4.5, and 5.5 dB) from baseline.

RESULTS

Data from 352 eyes in the CS-HMS arm and 165 in the CS arm were analyzed (2966 VFs). The mean RoP was -0.26 dB/y (95% credible interval -0.36, -0.16) for CS-HMS and -0.49 dB/y (95% credible interval -0.63, -0.34) for CS. This difference was significant (P = .0138). The difference in IOP only explained 17% of the effect (P < .0001). Five-year survival analysis showed an increased probability of VF worsening by 5.5 dB (P = .0170), indicating a greater proportion of fast progressors in the CS arm.

CONCLUSIONS

CS-HMS has a significant effect on VF preservation in glaucoma patients compared with CS alone, reducing the proportion of fast progressors.

A feasibility study for objective evaluation of visual acuity based on pattern-reversal visual evoked potentials and other related visual parameters with machine learning algorithm

BACKGROUND

To develop machine learning models for objectively evaluating visual acuity (VA) based on pattern-reversal visual evoked potentials (PRVEPs) and other related visual parameters.

METHODS

Twenty-four volunteers were recruited and forty-eight eyes were divided into four groups of 1.0, 0.8, 0.6, and 0.4 (decimal vision). The relationship between VA, peak time, or amplitude of P100 recorded at 5.7°, 2.6°, 1°, 34', 15', and 7' check sizes were analyzed using repeated-measures analysis of variance. Correlations between VA and P100, contrast sensitivity (CS), refractive error, wavefront aberrations, and visual field were analyzed by rank correlation. Based on meaningful P100 peak time, P100 amplitude, and other related visual parameters, four machine learning algorithms and an ensemble classification algorithm were used to construct objective assessment models for VA. Receiver operating characteristic (ROC) curves were used to compare the efficacy of different models by repeated sampling comparisons and ten-fold cross-validation.

RESULTS

The main effects of P100 peak time and amplitude between different VA and check sizes were statistically significant (all P < 0.05). Except amplitude at 2.6° and 5.7°, VA was negatively correlated with peak time and positively correlated with amplitude. The peak time initially shortened with increasing check size and gradually lengthened after the minimum value was reached at 1°. At the 1° check size, there were statistically significant differences when comparing the peak times between the vision groups with each other (all P < 0.05), and the amplitudes of the vision reduction groups were significantly lower than that of the 1.0 vision group (all P < 0.01). The correlations between peak time, amplitude, and visual acuity were all highest at 1° (r_s = - 0.740, 0.438). VA positively correlated with CS and spherical equivalent (all P < 0.001). There was a negative correlation between VA and coma aberrations (P < 0.05). For different binarization classifications of VA, the classifier models with the best assessment efficacy all had the mean area under the ROC curves (AUC) above 0.95 for 500 replicate samples and above 0.84 for ten-fold cross-validation.

CONCLUSIONS

Machine learning models established by meaning visual parameters related to visual acuity can assist in the objective evaluation of VA.

Remote Contrast Sensitivity Testing Seems to Correlate With the Degree of Glaucomatous Macular Damage

PRCIS

Remote contrast sensitivity (CS) testing through a free downloadable home test correlates with glaucomatous macular damage measured by 10-2 visual field (VF) testing.

PURPOSE

To assess the feasibility and validity of home CS monitoring as a measure of glaucomatous damage using a free downloadable smartphone application.

METHODS

Twenty-six participants were asked to remotely use the Berkeley Contrast Squares (BCS) application, a free downloadable tool that records the user's CS for varying degrees of visual acuity. An instructional video detailing how to download and use the application was sent to the participants. Subjects were asked to send logarithmic CS results with a minimum 8-week test-retest window, and test-retest reliability was measured. Results were validated against office-based CS testing that was collected within the previous 6 months. Validity analysis was also carried out to determine whether CS as measured by BCS is a good predictor of 10-2 and 24-2 VF mean deviation (MD).

RESULTS

There was a high BCS test-retest reliability with an intraclass correlation coefficient score of 0.91 and a significant correlation between repeat test results and baseline test scores (Pearson, 0.86, P < 0.0001). There was significant agreement between unilateral CS scores as measured by BCS and office-based CS testing ( b = 0.94, P < 0.0001, 95% CI: 0.61 to 1.27). Unilateral CS as measured by BCS was significantly associated with 10-2 VF MD ( r2 = 0.27, P = 0.006, 95% CI: 3.7 to 20.6), but not with 24-2 VF MD ( P = 0.151).

CONCLUSION

This study suggests that a free, rapid home CS test correlates with glaucomatous macular damage as measured by 10-2 VF.

Collective endpoint of visual acuity and contrast sensitivity function from hierarchical Bayesian joint modeling

Clinical trials typically analyze multiple endpoints for signals of efficacy. To improve signal detection for treatment effects using the high-dimensional data collected in trials, we developed a hierarchical Bayesian joint model (HBJM) to compute a five-dimensional collective endpoint (CE5D) of contrast sensitivity function (CSF) and visual acuity (VA). The HBJM analyzes row-by-row CSF and VA data across multiple conditions, and describes visual functions across a hierarchy of population, individuals, and tests. It generates joint posterior distributions of CE5D that combines CSF (peak gain, peak frequency, and bandwidth) and VA (threshold and range) parameters. The HBJM was applied to an existing dataset of 14 eyes, each tested with the quantitative VA and quantitative CSF procedures in four Bangerter foil conditions. The HBJM recovered strong correlations among CE5D components at all levels. With 15 qVA and 25 qCSF rows, it reduced the variance of the estimated components by 72% on average. Combining signals from VA and CSF and reducing noises, CE5D exhibited significantly higher sensitivity and accuracy in discriminating performance differences between foil conditions at both the group and test levels than the original tests. The HBJM extracts valuable information about covariance of CSF and VA parameters, improves precision of the estimated parameters, and increases the statistical power in detecting vision changes. By combining signals and reducing noise from multiple tests for detecting vision changes, the HBJM framework exhibits potential to increase statistical power for combining multi-modality data in ophthalmic trials.

The effect of filters and varying illumination on contrast sensitivity in eyes with moderate to severe visual impairment

PURPOSE

To investigate the effect of filters and illumination on contrast sensitivity in persons with cataract, pseudophakia, maculopathy and glaucoma to provide a guide for eye care providers in low vision rehabilitation.

MATERIALS AND METHODS

A within-subjects experimental design with a counter-balanced presentation technique was employed in this study. The contrast sensitivity of eyes with cataract, pseudophakia, maculopathy and glaucoma was measured with filters (no filter, yellow, pink and orange) combined with increasing illumination levels (100 lx, 300 lx, 700 lx and 1000 lx) using the SpotChecks™ contrast sensitivity chart. The data were analyzed using descriptive statistics and two-way repeated measures ANOVA.

RESULTS

The yellow filter at 100 lx significantly improved contrast sensitivity in the maculopathy group. There were no significant improvements with either intervention in the rest of the groups. There was, however, a significant interaction between filters and illumination in the cataract group.

CONCLUSION

There were small improvements in contrast sensitivity at low illumination levels with the yellow filter in the maculopathy group, and this could be considered in clinical practice and low vision rehabilitation. Overall, filters at most illumination levels did not benefit most groups.

Beyond vision:Cataract and health status in old age, a narrative review

Cataract is a leading cause of visual impairment in old age. Lens opacification is notoriously associated with several geriatric conditions, including frailty, fall risk, depression and cognitive impairment. The association is largely attributable to visual impairment, while other mechanisms, associated with extraocular comorbidity and lifestyle, might partly explain this correlation. Available literature suggests that cataract surgery may be effective in decreasing fall risk, improving depressive symptoms and limiting the risk of cognitive impairment and dementia incidence, although intervention studies on these outcomes are still limited. In this review we also emphasize the need to move from the concept of visual acuity to functional vision, especially in the context of the geriatric patient. Research is needed regarding the effect on the cited outcomes of different cataract treatment strategies, such as systematic bilateral versus monolateral surgery and use of different intraocular lenses.

Contrast sensitivity in glaucoma patients with visual field defects at different locations

Contrast sensitivity (CS) is closely associated with vision-related quality of life in glaucoma patients. This cross-sectional study was performed to determine the relationship between CS and visual field (VF) sensitivity (VFS) according to the hemifield location of VF defects in 238 patients with primary open-angle glaucoma (POAG) who underwent 24-2 standard automated perimetry and CS measurement on the same day. Of the 238 eyes, 83, 58, and 47 eyes had VF defects in the superior, inferior and both hemifields, respectively, and 50 had no VF defects in either hemifield. Significant correlations between CS and VFS in all sectors were observed in the entire cohort (R² = 0.103-0.315, all P < 0.001). However, CS poorly represented VF defects in eyes with single superior (R² = 0.037-0.086) or inferior (R² = 0.107-0.222) hemifield defects. Eyes with bi-hemifield VF defects showed significant correlations between VFS and CS at 0.3 m in all sectors (R² = 0.200-0.406), but the correlation between VFS and CS at 5 m was significant only in the inferior sector (R² = 0.224-0.348 vs. 0.081-0.126 in the inferior and superior sectors, respectively). Correlations between CS and VFS were dependent on CS distances and the presence of bi-hemifield VF defects. Although CS may not correlate with VFS in eyes with single-hemifield VF defects, it may reflect visual disability in eyes with bi-hemifield defects.

Implantation of diffractive extended depth-of-focus intraocular lenses in normal tension glaucoma eyes: A case series

Purpose

Implantation of presbyopia-correcting intraocular lenses (IOLs) has not been advised for glaucomatous eyes because of the risk of decreased contrast sensitivity with progress of glaucoma. Extended depth-of-focus (EDF) IOLs have been reported to provide comparable postoperative visual function and influence on the visual field to monofocal IOLs.

Methods

This case series was a retrospective medical record review of 16 eyes of 10 patients who had normal tension glaucoma (NTG) with no central visual field defects and underwent cataract surgery with implantation of diffractive EDF IOLs. At 3 months postoperatively, distance-corrected visual acuities (DCVAs) at distances of 5, 1, and 0.5 m and photopic contrast sensitivity were examined. Automated perimetry using the 30-2 Swedish interactive threshold algorithm was also performed, and the mean variance (MD) values, mean deviation values at the central four points (central MD), and foveal threshold were recorded.

Results

The mean age of the patients (5 men, 5 women) was 66.5 years. Over 80% of eyes obtained DCVAs of 20/20, 20/20, and 20/25 at 5 m, 1 m, and 0.5 m, respectively. Whereas 5 of 16 eyes were categorized as severe by the Hodapp-Parrish-Anderson classification, postoperative contrast sensitivity was within the normal range, except for 4 eyes at 18 cycles per degree.

Conclusions and importance

In this case series, the postoperative visual functions of NTG patients with EDF IOLs were almost comparable to those of normal eyes with the same IOLs, which demonstrated that the use of EDF IOLs for controlled NTG eyes would be permissible. While careful patient selection and follow-up for NTG progress are important, further investigations are necessary for confirming the safety and exploring the selection criteria.

Visual Acuity Outcomes in Diseases Associated with Reduced Visual Acuity: An Analysis of the National Health Insurance Service Database in Korea

Visual acuity declines with age, and disease-related visual acuity changes vary. We evaluated factors affecting visual acuity and age-related visual acuity in diseases associated with reduced visual acuity such as hypertension, diabetes mellitus (DM), glaucoma, and diabetic retinopathy (DR). The Korean National Health Insurance Service 2015–2016 data were analyzed for age-related visual acuity changes and prevalence of diseases associated with reduced visual acuity. Among 993,062 participants, the prevalence rates of hypertension, DM, glaucoma, and DR were 27.0%, 15.1%, 13.8%, and 2.7%, respectively. Despite having the lowest prevalence, DR alone or DR with hypertension and glaucoma resulted in low visual acuity. Correlation analysis between disease frequency and mean age-related visual acuity revealed higher positive correlations in DR and hypertension than in DM and glaucoma, indicating lower visual acuity. Odds ratios for low visual acuity in cases including one disease such as hypertension, DM, glaucoma, and DR were 1.73, 1.23, 1.04, and 1.52, respectively. The prevalence and number of diseases associated with reduced visual acuity increased with age, and visual acuity decreased. The leading causes of vision loss were DR as a single disease and hypertension as a concomitant disease. Therefore, age-related vision management, through periodic eye examination and correction with age, should be performed along with management of diabetes and hypertension.

Foveal crowding appears to be robust to normal aging and glaucoma unlike parafoveal and peripheral crowding

Visual crowding is the inability to recognize a target object in clutter. Previous studies have shown an increase in crowding in both parafoveal and peripheral vision in normal aging and glaucoma. Here, we ask whether there is any increase in foveal crowding in both normal aging and glaucomatous vision. Twenty-four patients with glaucoma and 24 age-matched normally sighted controls (mean age = 65 ± 7 vs. 60 ± 8 years old) participated in this study. For each subject, we measured the extent of foveal crowding using Pelli's foveal crowding paradigm (2016). We found that the average crowding zone was 0.061 degrees for glaucoma and 0.056 degrees for age-matched normal vision, respectively. These values fall into the range of foveal crowding zones (0.0125 degrees to 0.1 degrees) observed in young normal vision. We, however, did not find any evidence supporting increased foveal crowding in glaucoma (p = 0.375), at least in the early to moderate stages of glaucoma. In the light of previous studies on foveal crowding in normal young vision, we did not find any evidence supporting age-related changes in foveal crowding. Even if there is any, the effect appears to be rather inconsequential. Taken together, our findings suggest unlike parafoveal or peripheral crowding (2 degrees, 4 degrees, 8 degrees, and 10 degrees eccentricities), foveal crowding (<0.25 degrees eccentricity) appears to be less vulnerable to normal aging or moderate glaucomatous damage.

Contrast Sensitivity Changes after Phototherapeutic Keratectomy in Heterozygote Granular Corneal Dystrophy Type 2

Purpose: Contrast sensitivity, the ability to distinguish the relative difference in luminance of an object from its surrounding or adjacent objects, is a useful measure of visual function. In granular corneal dystrophy type 2 (GCD2), opacity of the corneal stroma causes deterioration in visual function. We compared the contrast sensitivity of GCD2 patients before and after phototherapeutic keratectomy (PTK) to evaluate the perioperative visual function in these patients.Methods: This study included 22 eyes of heterozygote GCD2 patients. The visual acuity and contrast sensitivity were measured before and after PTK. The contrast sensitivity was measured in mesopic and photopic background luminances, with glare (G) levels of 0-2 (G0, G1, and G2, respectively) and spatial frequencies at 1.5, 3, 6, 12, and 18 cycles per degree (cpd).Results: The contrast sensitivity increased after PTK at 1.5 and 3 cpd in mesopic and photopic conditions with G0-2 glare (p < 0.05). At 6 cpd, the contrast sensitivity increased in the mesopic condition with G1 glare, and in the photopic condition with G0-2 glare (p < 0.05). However, there was no change in contrast sensitivity at any glare level at 12 and 18 cpd after PTK.Conclusions: In GCD2 patients, the contrast sensitivity increased significantly after PTK. The vision of GCD2 patients, which is decreased due to corneal opacity, is improved after PTK.

Comparison of near vision in glaucoma patients using standard and reversed-contrast charts

CLINICAL RELEVANCE

Reversed-contrast testing is easy to perform via electronic devices and may improve reading performance and the quality of life of most glaucoma patients.

BACKGROUND

Electronic devices are becoming increasing popularity and most devices have easily adjustable contrast settings. This study investigated near vision acuity and preference between the standard visual acuity chart (black text on white background) and a reversed-contrast chart (white text on black background) in glaucoma patients with decreasing contrast sensitivity.

METHODS

This cross-sectional study evaluated 177 eyes of 177 patients from a single glaucoma clinic. The better eye of primary glaucoma patients (visual acuity of 6/20 or better) was evaluated. Patients with any other condition affecting visual acuity or reading performance were excluded. Near visual acuity was measured using a device with an anti-glare screen at 40 cm distance for both standard and reversed-contrast charts.

RESULTS

Glaucoma patients had a significantly better average near visual acuity using the reversed-contrast chart than using the standard chart (median best-corrected visual acuity, LogMAR = 0.12; interquartile range = 0.18 vs median best-corrected visual acuity, LogMAR = 0.2; interquartile range = 0.26; respectively; P < 0.01), with more prominent differences in the advanced glaucoma group (median best-corrected visual acuity of reversed contrast chart: median best-corrected visual acuity of standard chart = 0.12:0.2, 0.12:0.13, and 0.18:0.22 in the early, moderate, and severe groups, respectively, P < 0.01 in early and severe group and P = 0.02 in moderate group). One hundred and nine (109) out of 177 patients (61.58%) preferred the reversed contrast version.

CONCLUSION

Reversed contrast materials may improve the reading performance and quality of life of patients with glaucoma, especially those with severe disease.

Visual deterioration in patients with photoreceptor loss after retinal reattachment surgery

PURPOSE

Assess the relationship between photoreceptor degeneration and visual function after retinal reattachment surgery (RRS) in a prospective cohort.

METHODS

Patients with rhegmatogenous retinal detachment (RRD) were reviewed before and 6 months after vitreoretinal surgery. Optical coherence tomographical thickness of the outer nuclear layer (ONL), outer retinal segment (ORS), retinal pigmented epithelium to ellipsoid zone (RPE-EZ) and external limiting membrane to EZ (ELM-EZ) were recorded 6 months post-operatively. These were compared to best corrected visual acuity (BCVA) and retinal sensitivity (Humphrey visual field).

RESULTS

Thirteen macula-off and 8 macula-on RRD patients were included. The mean ONL thickness was higher after macula-on RRD compared to macula-off RRD (97.70 ± 3.62 μm vs. 73.10 ± 4.98 μm). In all RRD eyes, every 1 μm decrease in ONL thickness correlated with a 0.052 dB decrease and in retinal sensitivity and every 1 μm decrease in ORS thickness was associated with a 0.062 dB reduction in retinal sensitivity. ORS, ELM-EZ and RPE-EZ thickness did not correlate with BCVA post-RRS.

CONCLUSION

There was greater ONL and ORS thinning following macula-off compared to macula-on RRD. Correlations between ONL and ORS thinning with decreased retinal sensitivity may be explained by RRD-induced photoreceptor death.

Effect of red ginseng on visual function and vision-related quality of life in patients with glaucoma

Background

Red ginseng has been found to improve ocular perfusion and dry eye syndrome in glaucomatous eyes; however, its effects on visual function and vision-related quality of life have not been investigated. This study sought to evaluate the effects of red ginseng on visual function and vision-related quality of life in glaucoma patients using contrast sensitivity and a questionnaire.

Methods

Participants were randomly assigned to two groups in this prospective, randomized, double-blind study: in one group, red ginseng was taken first, followed by a placebo, and in the other, placebo was taken first, followed by red ginseng. We measured and compared changes in contrast sensitivity and vision-related quality of life between the two groups. Contrast sensitivity was measured using OPTEC® 6500P, and vision-related quality of life was evaluated using the 25-item National Eye Institute Visual Function Questionnaire. One-way and two-way repeated measure analyses of variance were used for the comparison. Relationships between respective changes in dry eye syndrome and contrast sensitivity were also analyzed.

Results

Daytime contrast sensitivity and ocular pain improved after the administration of red ginseng. Nighttime contrast sensitivity was improved in early or moderate glaucoma. Improved contrast sensitivity was not associated with improvement in dry eye syndrome.

Conclusion

Red ginseng could improve contrast sensitivity and ocular pain in patients with glaucoma. The mechanism underlying improvement in contrast sensitivity appears to be associated with enhanced retinal perfusion or retinal ganglion cell function, but not dry eye syndrome.

Design and validation of a chart-based measure of the limits of spatial contrast sensitivity

PURPOSE

Current chart-based tests of spatial contrast sensitivity (SCS) with fixed or narrow frequency ranges (≤18 cycles/°) cannot characterise the limits of spatial contrast vision. Here we present the design and validation of a chart-based measure of the spatial contrast envelope.

METHODS

Following the principles of the standard visual acuity (Bailey-Lovie) and contrast sensitivity (Pelli-Robson) charts, a combined spatial-contrast and visual acuity chart was designed using a language-independent triangular symbol for a four-alternative forced-choice procedure plus chart rotation. Symbol frequencies ranged between 0.38 and 60 cycles/° spaced along 10 radial axes (0.55%-100% contrast). The chart was validated with reference to the Bailey-Lovie and Pelli-Robson charts; its reliability and sensitivity to changes in illumination, simulated cataract and blur was evaluated in healthy adults.

RESULTS

The photopic SCS function could be measured in 5.5 ± 0.5 min; thresholding around the spatial contrast resolution limit reduced completion times to ~2 min. There was good agreement with high-contrast visual acuity (difference = 0.08 ± 0.02 logMAR) and contrast-sensitivity at 1.5 cycles/° (0.13 ± 0.06 logCS). Test-retest reliability was excellent at all spatial frequencies (ICC = 0.99). Mesopic illumination or simulated cataract caused a generalised SCS loss; myopic blur reduced high-frequency sensitivity. Spatial contrast sensitivity was independent of radial axis orientation (cardinal or oblique).

CONCLUSIONS

The chart provides a time-efficient, reliable and inexpensive measure of SCS with applications in research and clinic for detecting subtle deficits in early stages of ocular and neurological conditions that often manifest at higher frequencies. It is sensitive to vision changes occurring in dim lighting and with simulated cataract and blur. The chart is available open-access for self-printing; contrast variation in print can be controlled through user calibration and/or establishing normative SCS functions using the theoretical values.

Patient Reported Symptoms Demonstrating an Association with Severity of Visual Field Damage in Glaucoma

OBJECTIVE

To determine which patient reported symptoms best distinguishes patients with and without glaucoma and explains the most variance in visual field (VF) damage, and compare the amount of variance that can be explained by symptoms vs. retinal nerve fiber layer (RNFL) thickness.

DESIGN

Cross-sectional study.

PARTICIPANTS

Adults diagnosed with glaucoma or suspicion of glaucoma (controls).

METHODS

Worse-eye VF damage was defined based on perimetric testing. RNFL thickness was defined by OCT imaging. Patients rated their visual symptoms on questions collated from several published questionnaires, rating the frequency and severity of 28 symptoms on a scale of 1 (never/not at all) to 4 (very often/severe). Multivariable regression models identified patient reported symptoms that contributed the highest variance in VF damage.

MAIN OUTCOME MEASURES

Patient reported symptoms that explained the most variance in VF damage; amount of variance in VF damage explained by patient reported symptoms and RNFL RESULTS: A total of 170 patients (mean age= 64; 58% female; 47% employed) completed testing, including 95 glaucoma suspects and 75 glaucoma patients. In glaucoma patients, median mean deviation of VF damage in the worse eye was -19.3 and ranged from -5.3 to -34.7 dB. Symptoms more common amongst glaucoma patients compared to glaucoma suspects included better vision in one eye, blurry vision, glare, sensitivity to light, cloudy vision, and little peripheral vision. Worse severity ratings for the symptom 'little peripheral vision' explained the most variance in VF damage (43%). A multivariable model including the frequency of cloudy vision, severity of having little peripheral vision, missing patches, one eye having better vision, and vision worsening, plus sociodemographic features explained 62% of the variance in VF damage. Comparatively, a multivariable model of worse-eye RNFL thickness and sociodemographic features explained 42% of the variance in VF damage, while a model including only sociodemographic features explained 8% of the variance in VF damage.

CONCLUSIONS

Five patient reported symptoms explain a significant amount of the variance in VF damage. Asking patients about their symptoms may optimize patient-physician communication and be a useful adjunct to clinical testing in some patients to estimate disease severity.

Comparing the CamBlobs2 contrast sensitivity test to the near Pelli-Robson contrast sensitivity test in normally-sighted young adults

PURPOSE

Contrast sensitivity (CS) has been proposed as a potential method for patients to assess their vision at home. The CamBlobs2 contrast sensitivity test is meant to be performed easily in the clinic or at home. The purpose of this study was to determine the intra-visit coefficient of repeatability of the CamBlobs2 compared with the near Pelli-Robson test, and the limits of agreement between these two tests on normally-sighted subjects.

METHODS

Twenty-two normally-sighted subjects (mean age 28 ± 4 years) completed two trials of the near Pelli-Robson and CamBlobs2 contrast sensitivity tests within a single visit. Tests were performed monocularly on each eye in random order. Pelli-Robson tests were scored as 0.05 logCS for each letter read correctly after deducting the first triplet. CamBlob2 tests were scored as the highest line where two or fewer blobs were marked correctly. The coefficient of repeatability was determined as 1.96 times the standard deviation of the difference between the two measurements using the same type of chart on the same eye. The limits of agreement between the two tests were evaluated using Bland-Altman analysis.

RESULTS

The mean difference between intra-visit measurements for both the near Pelli-Robson and CamBlobs2 was less than 0.05 logCS and the coefficient of repeatability was within ±0.20 log CS for both left and right eyes. The mean ± standard deviation differences between near Pelli-Robson and CamBlobs2 scores was -0.08 ± 0.08 (limits of agreement: -0.24 to 0.09) for right eyes and -0.05 ± 0.10 (limits of agreement: -0.23 to 0.14) logCS for left eyes based on average measurements.

CONCLUSIONS

The intra-visit repeatability of CamBlobs2 was consistent with the near Pelli-Robson contrast sensitivity test (±0.20 logCS). With a 0.05 correction, the CamBlobs2 scores showed excellent agreement with the near Pelli-Robson contrast sensitivity test.

Neuroprotection of the Inner Retina Also Prevents Secondary Outer Retinal Pathology in a Mouse Model of Glaucoma

Purpose

We examined structural and functional changes in the outer retina of a mouse model of glaucoma. We examined whether these changes are a secondary consequence of damage in the inner retina and whether neuroprotection of the inner retina also prevents outer retinal changes.

Methods

We used an established microbead occlusion model of glaucoma whereby intraocular pressure (IOP) was elevated. Specific antibodies were used to label rod and cone bipolar cells (BCs), horizontal cells (HCs), and retinal ganglion cells (RGCs), as well as synaptic components in control and glaucomatous eyes, to assess structural damage and cell loss. ERG recordings were made to assess outer retina function.

Results

We found structural and functional damage of BCs, including significant cell loss and dendritic/axonal remodeling of HCs, following IOP elevation. The first significant loss of both BCs occurred at 4 to 5 weeks after microbead injection. However, early changes in the dendritic structure of RGCs were observed at 3 weeks, but significant changes in the rod BC axon terminal structure were not seen until 4 weeks. We found that protection of inner retinal neurons in glaucomatous eyes by pharmacological blockade of gap junctions or genetic ablation of connexin 36 largely prevented outer retinal damage.

Conclusions

Together, our results indicate that outer retinal impairments in glaucoma are a secondary sequalae of primary damage in the inner retina. The finding that neuroprotection of the inner retina can also prevent outer retinal damage has important implications with regard to the targets for effective neuroprotective therapy.

High-Pass Visual Acuity Loss and Macular Structure-Function Relationship in Patients With Primary Open-Angle Glaucoma

Purpose

The Logarithm of the Minimum Angle of Resolution (logMAR) chart is the most common clinical test for assessing central visual function in glaucoma. However, based on the use of these charts, visual acuity (VA) often remains normal even when severe macular damage exists. Here, we aim to investigate the potential advantages of high-pass VA in detecting glaucoma compared with conventional VA.

Methods

Monocular best-corrected VA measurements were compared for a novel high-pass electronic VA chart (e-chart) and a conventional e-chart in 113 primary open-angle glaucoma (POAG) patients with normal logMAR VA and 65 age-similar healthy controls. One hundred thirty-nine POAG patients underwent spectral-domain optical coherence tomography (SD-OCT) for measurement of macular ganglion cell layer plus inner plexiform layer (GCL+IPL) thickness. Structure-function relationships between OCT measurements and the two VAs were compared. The enrolled eyes were divided into two groups for further analyses according to macular visual field (MVF) defects, specifically two or more adjacent abnormal points within the 12 central sites of 30-2 VF.

Results

The mean deviation (MD) of 30-2 VF test was -12.77 ± 7.47 dB for glaucoma group and -1.70 ± 1.12 dB for control group. The mean difference of the two VAs was slightly larger in glaucoma group (0.29 logMAR) than in control group (0.22 logMAR). The area under the receiver operating characteristic curve of the high-pass e-chart was larger than that of conventional e-chart (0.917 vs. 0.757, P < 0.001). Significant correlations between high-pass VA and GCL+IPL thickness were found only in the MVF-damaged group. Compared with conventional VA, high-pass VA demonstrates stronger correlations with nasal-side macular GCL+IPL thickness (Fisher's Z-test, two-tailed, P2mmin diameter = 0.033 and P3mmin diameter = 0.005).

Conclusions

Compared with conventional VA, high-pass VA displays slightly higher sensitivity to visual loss in glaucoma and has a stronger correlation with the nasal-side macular GCL+IPL thickness.

Translational Relevance

The high-pass acuity test has the potential to be used as an ancillary tool to monitor glaucoma over time.

Visual Acuity in Glaucomatous Eyes Correlates Better with Visual Field Parameters than with OCT Parameters

The visual acuity is very important for glaucoma patients in their lives. The purpose of this study was to examine about the correlation of visual acuity and visual field (VF) parameters or optical coherence tomography (OCT) parameters in patients with glaucoma. We evaluated 210 eyes of 210 patients (110 men and 100 women; mean age, 69.6 ± 9.6 years) with open-angle glaucoma and 68 eyes of healthy controls. In glaucomatous eyes including healthy eyes, correlation between visual acuity and each of the VF parameters or each of the OCT parameters was estimated using regression analyses. The average visual acuity of control group was - 0.08, and that of glaucoma group was - 0.06 (early stage), - 0.03 (moderate stage), and 0.08 (severe stage), respectively. Regression analyses including healthy eyes and glaucomatous eyes revealed significant correlations between visual acuity and mean deviation (MD) of 30-2 Humphrey VF (rs = - 0.44), MD of 10-2 VF (rs = - 0.45), total deviation in central 10-2 VF (rs = - 0.42), ganglion cell complex thickness (macula, rs = - 0.33; superior, rs = - 0.33; inferior, rs = - 0.35; and global, rs = - 0.34), and circumpapillary retinal nerve fiber layer (rs = - 0.38). The visual acuity of glaucomatous eyes correlated with VF parameters and OCT parameters. The visual acuity decreased as glaucoma progressed.

Development of an experimental model for ocular toxicity screening in Zebrafish

BACKGROUND

To investigate the efficacy of a novel experimental model for exploring visual function using a contrast-optomotor response (C-OMR) assay made by applying the contrast sensitivity test to the OMR assay in zebrafish.

METHODS

Zebrafish larvae were treated with 0 (control), 5, 10, or 15 μM gentamicin and digoxin for 24 h at four days post-fertilization (dpf). Zebrafish larvae were assessed using the C-OMR assay with graded contrast gray-white stripes at 5 dpf, and the results were expressed as the percentage of larvae that finished swimming for 30 s (n = 20 per each group). The same C-OMR assay was repeated four times using different larvae.

RESULTS

The percentage of larvae that finished swimming within 30 s was significantly reduced in larvae treated with 5, 10, and 15 μM gentamicin and 10 and 15 μM digoxin as compared to the Control groups. The C-OMR assay could distinguish that the decrease in visual function was different depending on the concentration of gentamicin and digoxin (5, 10, and 15 μM), whereas the OMR test with one contrast gray-white stripe could not.

CONCLUSIONS

The method of analyzing zebrafish OMR using graded contrast gray-white stripes is more sensitive than the OMR assay alone and may be more useful for assessing the drug toxicity and eye-related diseases to improve the understanding of drug-induced ocular side effects in the clinic.

Assessing glaucoma deterioration using Spaeth/Richman contrast sensitivity test

Purpose:

To assess changes in the central and peripheral contrast sensitivity in severe primary open-angle glaucoma (POAG) patients using a computer-based Spaeth/Richman contrast sensitivity test (SPARCS) over a period of 24 months.

Methods:

Our pilot, observational study included 15 patients (30 eyes) with severe POAG. Visual acuity, intraocular pressure, number of anti-glaucoma drugs, visual fields, and SPARCS score were recorded at first visit and at 12 and 24 months.

Results:

We observed changes in mean deviation (MD) from −19.37 ± 5.04 to −20.63 ± 4.07, mean pattern standard deviation (PSD) from 11.49 ± 2.61 to 11.35 ± 2.01, and mean SPARCS score from 54.97 ± 15.66 to 53.50 ± 16.42. We found no statistically significant difference between visual field parameters and SPARCS scores associated with the number or type of prescribed anti-glaucoma drugs. Spearman’s correlation coefficient of SPARCS at baseline (SPARCS1) versus MD at baseline (MD1) was 0.274 (p = 0.142) and SPARCS1 versus PSD at baseline (PSD1) was −0.163 (p = 0.389). The correlation coefficient between SPARCS at 12 months (SPARCS2) versus MD (MD2) at the same time point was computed to be 0.391 (p = 0.03), whereas SPARCS2 versus PSD at 12 months was −0.212 (p = 0.262). Similarly, we found the coefficient to be 0.336 (p = 0.069) for SPARCS3 (SPARCS at 24 months) versus MD3 (MD at 24 months) and −0.242 (p = 0.197) for SPARCS3 versus PSD3 (PSD at 24 months). Correlation coefficients between SPARCS1/2, SPARCS1/3, MD1/2, MD1/3 PSD1/2, and PSD1/3 were 0.856, 0.865, 0.748, 0.722, 0.497, and 0.562, respectively (p < 0.001). MD changed by 9.46% ± 12.73%, PSD by 0.64% ± 14.03%, and average SPARCS by 3.31% ± 12.73% over 24 months.

Conclusion:

The data from our study indicate the utilitarian application of SPARCS, an inexpensive and readily available tool for monitoring functional deterioration in cases with advanced glaucomatous damage, especially in resource-poor settings. Furthermore, it is a useful and reliable alternative to the imaging modalities where retinal nerve fiber layer measurement can be erroneous in advanced cases secondary to the floor effect.

Spaeth/Richman Contrast Sensitivity in Staging Glaucoma

Purpose

To investigate contrast sensitivity measures in glaucoma eyes with moderate to severe glaucoma.

Methods

The study included 50 eyes of 47 pseudophakic patients with moderate or severe glaucoma who were seen at a tertiary center from 2017 to 2020. Assessment of contrast sensitivity using the Spaeth/Richman contrast sensitivity (SPARCS) test and the Pelli-Robson (PR) chart was compared in eyes with mean deviation (MD) < -12 decibels (dB) and > -20 dB (group 1), MD < -20 dB and > -30 dB (group 2), or MD < -30 dB (group 3). Multivariate regression analysis was used to analyze the association of visual field MD with SPARCS/PR scores and various clinical variables, including age, diagnosis, and logMar visual acuity.

Results

SPARCS total scores and quadrant-wise scores were significantly different in all of the quadrants, whereas central scores and PR contrast sensitivity were similar across groups. The total SPARCS scores predicted the change in MD (β = 0.5, P < 0.001, R ² = 61.8%) with minimal association of other quadrantic or PR scores. Total SPARCS scores of <45 and <38 predicted severe glaucoma with MD crossing -20 dB (sensitivity, 70.5%; specificity, 80.9%) and -30 dB (sensitivity, 79.3%; specificity, 77.7%), respectively. The logMar visual acuity did not correlate with any contrast sensitivity measure or clinical variables in this study.

Conclusions

The total SPARCS score may be used in staging glaucoma severity and to assess visual function in eyes with severe glaucoma.

Translational Relevance

The SPARCS test is a useful tool for assessing visual function in advanced glaucoma beyond MD worse than -20 dB or -30 dB.

Influence of extended depth of focus intraocular lenses on visual field sensitivity

Purpose

To investigate the influence of EDOF IOLs, TECNIS Symfony^® (Johnson & Johnson Surgical Vision, Inc.), on visual field sensitivity and to compare the IOLs with other kinds of IOLs.

Methods

The subjects included the normal fellow eyes of patients who underwent the Humphrey Field Analyzer (HFA) 30–2 with Swedish Interactive Threshold Algorithm Fast within 6 months after cataract due to glaucoma or suspected glaucoma. Each parameter of HFA was compared among eyes implanted with TENIS Symfony^® (EDOF group), diffractive bifocal IOLs (bifocal group), and monofocal IOLs (monofocal group).

Results

The total of 76 eyes, including 24 eyes in the EDOF group, 26 eyes in the bifocal group, and 26 eyes in the monofocal group, were included in this study. Mean deviation (MD) of HFA was -0.24±0.58 dB in the EDOF group, -1.38±0.58 dB in the bifocal group, and 0.02±0.44 dB in the monofocal group. Foveal threshold (FT) of HFA was 35.8±1.6 dB in the EDOF group, 33.6±1.7 dB in the bifocal group, and 36.6±1.4 dB in the monofocal group. In both MD and FT, there was significant difference between the bifocal group and the others (p<0.001). There was no difference between the EDOF group and the monofocal group. Moreover, there was no significant difference between the three groups about pattern standard deviation (PSD) of HFA.

Conclusion

TECNIS Symfony^® may have little influence on visual field sensitivity, whereas diffractive bifocal IOLs decrease visual field sensitivity.

A critical review: Psychophysical assessments of diabetic retinopathy

Diabetic retinal disease remains a leading cause of vision loss despite currently available screening methods, ocular treatments, and efforts to control metabolic dysfunction. It is now understood that diabetes damages the entire retina and the cellular components of the neurovascular unit. Multiple studies have demonstrated impairment of various aspects of retinal function across the spectrum of retinopathy severity. Here we review these tests, the principles underlying their use, clinical data from multiple publications, the strengths and limitations of the studies, and prospects for their application to understand the pathophysiology of diabetic retinal disease and monitor its response to therapy. We focus on visual acuity, contrast sensitivity, color vision, visual field, and dark adaptation and their use to understand the pathophysiology of diabetic retinopathy and as potential endpoints for clinical trials.

An Open-source Static Threshold Perimetry Test Using Remote Eye-tracking (Eyecatcher): Description, Validation, and Preliminary Normative Data

Purpose

To describe, validate, and provide preliminary normative data for an open-source eye-movement perimeter (Eyecatcher).

Methods

Visual field testing was performed monocularly in 64 normally sighted young adults, using (i) a Humphrey Field Analyzer (HFA) and (ii) the novel Eyecatcher procedure. Eyecatcher used a remote eye-tracker to position stimuli relative to the current point of fixation, and observers responded by looking towards the stimulus. In both tests, Goldman III stimuli were sampled from a 24-2 grid, and were presented against a 10 cd/m² background. Participants completed each test twice to assess test–retest repeatability.

Results

Mean Sensitivity (MS) did not differ between Eyecatcher and the HFA (P = 0.086), and both tests exhibited similar test–retest repeatability (CoR_Eyecatcher = ±1.86 dB; CoR_HFA = ±1.95 dB). Eyecatcher was also able to detect changes in sensitivity across the normal visual field (the “Hill of Vision”), and could differentiate the physiological blind spot from adjacent retinal locations. Mean sensitivities and 95% limits of agreement are described for each pointwise location.

Conclusions

Eyecatcher can use eye movements to assess visual fields in young, normally sighted adults. In such observers, it provides results similar to the current gold standard clinical device (HFA).

Translational Relevance

Given further development, eye movement perimeters such as Eyecatcher could be particularly useful for individuals unable to perform traditional perimetric assessments, such as young children or stroke patients. Full technical details and information on how to freely acquire the source code are included.

Increased Equivalent Input Noise in Glaucomatous Central Vision: Is it Due to Undersampling of Retinal Ganglion Cells?

Purpose

Recent evidence shows that macular damage is common even in early stages of glaucoma. Here we investigated whether contrast sensitivity loss in the central vision of glaucoma patients is due to an increase in equivalent input noise (Neq), a decrease in calculation efficiency, or both. We also examined how retinal undersampling resulting from loss of retinal ganglion cells (RGCs) may affect Neq and calculation efficiency.

Methods

This study included 21 glaucoma patients and 23 age-matched normally sighted individuals. Threshold contrast for orientation discrimination was measured with a sinewave grating embedded in varying levels of external noise. Data were fitted to the linear amplifier model (LAM) to factor contrast sensitivity into Neq and calculation efficiency. We also correlated macular RGC counts estimated from structural (spectral-domain optical coherence tomography) and functional (standard automated perimetry Swedish interactive thresholding algorithm 10-2) data with either Neq or efficiency. Furthermore, using analytical and computer simulation approach, the relative effect of retinal undersampling on Neq and efficiency was evaluated by adding the RGC sampling module into the LAM.

Results

Compared with normal controls, glaucoma patients exhibited a significantly larger Neq without significant difference in efficiency. Neq was significantly correlated with Pelli-Robson contrast sensitivity and macular RGC counts. The results from analytical derivation and model simulation further demonstrated that Neq can be expressed as a function of internal noise and retinal sampling.

Conclusions

Our results showed that equivalent input noise is significantly elevated in glaucomatous vision, thereby impairing foveal contrast sensitivity. Our findings further elucidated how undersampling at the retinal level may increase equivalent input noise.

Relationship Between Acuity and Contrast Sensitivity: Differences Due to Eye Disease

Purpose

Visual acuity (VA) and contrast sensitivity (CS) characterize different aspects of visual function. Whereas VA is a standard test in routine eye exams and clinical trials, CS is often not included. We investigated the pathology-specific dissociation between VA and CS by quantifying and comparing the relationship between these two measures in common ocular pathologies.

Methods

VA and CS data were assembled from 1113 subjects, including groups with cataract (n = 450), age-related macular degeneration (AMD; n = 232), glaucoma (n = 100), retinitis pigmentosa (RP; n = 87), and normal ocular health (n = 244). VA and CS were measured by the Early Treatment Diabetic Retinopathy Study chart and Pelli-Robson chart, respectively.

Results

Even when VA was relatively normal (<0.3 logMAR), the four ocular pathology groups showed quantitatively different mean CS deficits relative to normal controls, ranging from -0.01 log units for cataract to 0.23 log units for RP. When the entire range of VA was considered, the corresponding deficits in CS were noticeably different across these four groups, being least for cataract and progressively more severe for glaucoma, AMD, and RP. For every 1.0 logMAR loss of VA, the corresponding deficit in CS ranged from 0.22 logCS for cataract to 0.97 logCS for RP.

Conclusions

The quantitative relationship between VA and CS depends on the ocular pathology. CS appears to provide valuable complementary information to VA in the early detection of eye disease and when evaluating visual impairment.

Relationship of Contrast Sensitivity Measured Using Quick Contrast Sensitivity Function With Other Visual Functions in a Low Vision Population

Purpose

Contrast sensitivity (CS) is predictive of various aspects of an individual's functional vision, such as recognizing faces and driving. Currently available CS charts are limited in terms of the spatial frequencies they can test and/or the contrast resolution of the targets they present. The traditional methods for measuring full CS functions (CSFs) are time consuming. The purpose of this study was to examine the feasibility of using the quick CSF method in a low vision population and to assess the relationships of CS with other visual functions, which can contribute to the understanding of the functional vision.

Methods

Static visual acuity, dynamic visual acuity, CS, global motion perception thresholds, and visual field were measured binocularly in 53 individuals with low vision. The number of participants who could complete each assessment was used to assess feasibility. The relationships between CS and other visual functions were assessed using linear regressions and multiple regressions.

Results

The quick CSF was quantifiable in 34 participants of the 42 with quantifiable visual acuities. The area under the log CSF—the summary statistic of CSF—was significantly correlated with static visual acuity and dynamic visual acuity (r = −0.79 and r = −0.63, respectively; P < 0.001).

Conclusions

The qCSF is capable of measuring CS in a wide range of visual impairment severities. area under the log CSF only correlates with measures of visual acuity.

Impact of Dry Eye on Visual Acuity and Contrast Sensitivity: Dry Eye Assessment and Management Study

SIGNIFICANCE

Identification of the association of specific signs of dry eye disease with specific visual function deficits may allow for more targeted approaches to treatment.

PURPOSE

The purpose of this study was to explore the association of dry eye signs and symptoms with visual acuity (VA) and contrast sensitivity in the Dry Eye Assessment and Management study.

METHODS

Baseline data from participants in the Dry Eye Assessment and Management study were used in this secondary cross-sectional analysis. Standardized procedures were used to obtain results on the Ocular Surface Disease Index (OSDI), high-contrast logMAR VA, contrast sensitivity, tear film debris, tear breakup time (TBUT), corneal fluorescein staining, meibomian gland evaluation, conjunctival lissamine green staining, and Schirmer test scores. Generalized linear models that included age, refractive error status, and cataract status were used to assess the association between VA and contrast sensitivity with OSDI score and each dry eye sign. The Hochberg procedure was used to account for multiple comparisons.

RESULTS

Among 487 participants (974 eyes), worse VA was associated with worse mean score on the OSDI vision subscale (39.4 for VA 20/32 or worse vs. 32.4 for VA 20/16 or better; adjusted linear trend, P = .02); scores were not associated with contrast sensitivity. Severe meibomian gland plugging and abnormal secretions were associated with worse mean log contrast sensitivity (1.48 for severe vs. 1.54 for not plugged [P = .04] and 1.49 for obstructed vs. 1.57 for clear [P = .002], respectively). Longer TBUT was associated with better mean log contrast sensitivity (1.57 for TBUT >5 seconds and 1.51 for TBUT ≤2 seconds, P < .0001).

CONCLUSIONS

Worse VA rather than worse contrast sensitivity drives vision-related symptoms in dry eye. Greater tear film instability was associated with worse contrast sensitivity.

Evaluation of contrast sensitivity in patients with advanced glaucoma: comparison of two tests

AIMS

To evaluate contrast sensitivity (CS) in patients with advanced glaucomatous visual field damage, and to compare two clinical CS tests.

METHODS

This was a cross-sectional test-retest study. Twenty-eight patients with open-angle glaucoma, visual acuity (VA) better than 20/40 and visual field mean deviation (MD) worse than -15 dB were enrolled. Patients underwent VA, visual field and CS testing with the Pelli-Robson (PR) chart and the Freiburg Visual Acuity and Contrast Test (FrACT). Retest measurements were obtained within 1 week to 1 month.

RESULTS

Median (IQR) age and MD were 61.5 (55.5 to 69.2) years and -27.7 (-29.7 to -22.7) dB, respectively. Median (IQR) VA was 0.08 logarithm minimum angle of resolution (0.02 to 0.16), corresponding to 20/25 (20/20 to 20/30). Median (IQR) CS was 1.35 (1.11 to 1.51) log units with the PR chart and 1.39 (1.24 to 1.64) log units with FrACT. VA explained less than 40% of the variance in CS (adjusted R²=0.36). CS estimates of both tests were closely related (rho=0.88, p=0.001), but CS was 0.09 log units higher with FrACT compared with the PR chart, and the 95% repeatability intervals (Bland-Altman) were 46% tighter with the PR chart.

CONCLUSIONS

Despite near-normal VA, almost all patients showed moderate to profound deficits in CS. CS measurement provides additional information on central visual function in patients with advanced glaucoma.

Precision and Normative Values of a New Computerized Chart for Contrast Sensitivity Testing

The purpose was to define a normative database for a grating test for contrast sensitivity, based on a chart monitor with high-definition liquid crystal display, and validate its measurements by assessing their repeatability and determining responsiveness to cataract surgery. Three samples were analyzed: (1) healthy volunteers to assess the repeatability of measurements, (2) healthy subjects to develop the normative database, (3) patients undergoing cataract surgery. All subjects were tested with the grating contrast sensitivity test (Vision Chart, CSO) at 1.5, 3, 6, 12 and 18 cycles per degree. The instrument software progressively reduces the contrast of the gratings according to the Quick Estimate by Sequential Testing (QUEST) procedure. In the subjects of the first sample, three consecutive measurements were taken and repeatability was assessed on the basis of the intra-session test-retest variability and the coefficient of variation. The test offered high repeatability, with test-retest variability ranging between 0.05 and 0.23 Log CS and the coefficient of variation between 0.61 and 4.21%. Normative data did not show a normal distribution. The highest median values were observed at 1.5, 3 and 6 cycles per degree frequencies. At these frequencies a ceiling effect was evident. In cataract patients, postoperative values showed an improvement at all spatial frequencies. In conclusion, the new contrast sensitivity test provides repeatable measurements that can be used for clinical purposes. In patients with healthy eyes and good vision, attention has to be paid to the ceiling effect.

Dominance wave propagation during binocular rivalry in mild glaucoma

Glaucoma is both a progressive optic neuropathy and a neurodegenerative disease affecting structures in the primary visual pathway. Other vision-associated areas may also be affected, including the corpus callosum which is involved in inter-hemispheric transfer. This study evaluated dominance wave propagation during binocular rivalry to probe the efficacy of the inter-hemispheric transfer in 20 patients with mild open angle glaucoma and 25 age-matched controls. The two groups were matched for functional measures such as stereo-acuity, binocular visual acuity, and visual field mean deviation. Monocular functional and structural measures were equivalent for the left and right eye of each participant. Using Wilson et al.'s travelling wave paradigm [Nature, 412 (2001) 907-910], intra- and inter-hemispheric failure rates of traveling wave transmission and the travelling wave propagation times were recorded for the two groups. For the control group, the wave propagation failure rate was significantly greater for the inter- than for the intra-hemispheric condition, but for the glaucoma group, the failure rates were equally high for the two conditions. The wave propagation time was significantly longer for the inter- than for the intra-hemispheric condition for the control group, while the opposite was true for the glaucoma group. These results reveal changes in the wave dynamics of rivalry dominance in patients with mild glaucoma who otherwise have normal performance on standard functional measures.

Measurable Aspects of the Retinal Neurovascular Unit in Diabetes, Glaucoma, and Controls

PURPOSE

To study the structural and angiographic optical coherence tomography (OCT) data of the macula from controls, patients with diabetes, and patients with glaucoma to evaluate neurovascular and structural relationships.

METHODS

This was a retrospective study of 89 eyes from 49 patients in a community-based retinal referral practice with diabetes, glaucoma, and normal controls. The patients were evaluated with OCT to include retinal nerve fiber layer (RNFL) thickness measurement and ganglion cell layer (GCL) volume determination. The vascular density of the radial peripapillary capillary network and the vascular plexuses in the macula were evaluated with OCT angiography. The main outcome measures were the data obtained per disease state and the interrelationships the data displayed.

RESULTS

The mean GCL volumes were significantly lower than the control group in both the diabetic (P = .016) and glaucoma (P < .001) groups. The difference between the diabetic and glaucoma groups was not significant (P = .052). The mean global vascular density was greater in the control group than the diabetic group (P = .002) and the glaucoma group (P < .001). The mean RNFL thicknesses were lowest in the glaucoma group. Both the diabetic and glaucoma groups had significantly lower radial peripapillary network and deep vascular plexus density values compared to controls.

CONCLUSIONS

Although there are important differences in disease pathogenesis between diabetes and glaucoma, they share certain similarities in the structural and angiographic abnormalities eventually produced. This suggests that, in addition to canonical pathways of disease, a component of both could represent neurodegenerative disease, offering the possibility for the development of new treatments. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Evaluation of Contrast Sensitivity after Four Different Treatment Modalities Using OPTEC-Functional Vision Analyzer in Primary Open-Angle Glaucoma

PURPOSE:

The purpose of the study is to evaluate the changes in contrast sensitivity (CS) after using the four different types of antiglaucoma eye drops in patients with primary open-angle glaucoma (POAG) by OPTEC-functional vision analyzer (FVA).

METHODS:

In this prospective study, eighty patients (80 eyes) with POAG were randomly divided into four groups. The groups were randomly received timolol maleate 0.5%, travoprost 0.004%, dorzolamide 2%, and brimonidine tartrate 0.2%. The medications were used in the eye that was randomly selected. The CS was assessed before and 15 min after the intervention by the FVA. The paired t-test was used to compare the difference between before and after the intervention. P < 0.05 was considered statistically significant.

RESULTS:

Fifteen minutes after the instillation of timolol maleate (Group A), the CS in three out of twenty patients at the spatial frequencies of 1.5, and 3 cycles per degree (cpd) was significantly decreased (P = 0.015). However, using travoprost (Group B) and dorzolamide (Group C), the CS in one out of twenty patients at low spatial frequencies (1.5 and 3 cpd) was decreased in the two groups, which was not statistically significant for these medications (P > 0.05). In Group D, after applying brimonidine tartrate, the CS in two out of twenty patients at the spatial frequency of 18 cpd was significantly decreased (P = 0.042).

CONCLUSION:

Our study showed that CS values at low and high spatial frequencies after applying timolol and brimonidine eye drops are temporarily reduced in patients with POAG.

Glaucoma-Associated Visual Task Performance and Vision-Related Quality of Life in South India

OBJECTIVE/PURPOSE

Performance-based measures may provide an objective assessment of how glaucoma affects daily functioning. We sought to validate a clinically-applicable performance-based measure of visual ability for patients with glaucoma in south India and to describe its relationship to clinical and patient-reported outcomes.

DESIGN

Cross-sectional validation study.

SUBJECTS/PARTICIPANTS/CONTROLS

145 participants with glaucoma were recruited at Aravind Eye Hospital.

METHODS/INTERVENTION/TESTING

We modified the compressed assessment of activities related to vision (CAARV), a performance-based measure validated in the U.S., to be culturally relevant in south India. Participants underwent a series of tests, including the Indian CAARV (I-CAARV), Indian Visual Functioning Questionnaire (IND-VFQ), Spaeth/Richman Contrast Sensitivity (SPARCS) test, standard automated perimetry, and visual acuity (VA). Factor analysis and Rasch modeling were used to validate the I-CAARV. Correlations between the I-CAARV and other outcomes were evaluated.

MAIN OUTCOME MEASURE

Psychometric properties of the I-CAARV for individuals with glaucoma in south India.

RESULTS

The study included 142 participants (51.7% female, mean age 56.4 years). Average presenting visual acuity and visual field mean deviation (MD) in the better-seeing eye were 0.26 logMAR and -6.57 dB, respectively. The four tasks of the I-CAARV were found to measure a single underlying construct. Rasch analysis of the I-CAARV revealed that the outcome measure had moderate reliability, good construct and content validity, and fair measurement precision. Tasks were well-targeted to the study sample. Rasch-calibrated scores on the I-CAARV were significantly correlated with Rasch-calibrated IND-VFQ scores (r=-0.54) and with visual field MD, presenting VA, best-corrected VA, and SPARCS contrast sensitivity in both the better-seeing eye (r=0.60, -0.51, -0.53, 0.76, respectively) and worse-seeing eye (r=0.48, -0.61, -0.46, 0.69, respectively).

CONCLUSIONS

The I-CAARV is a valid performance-based measure of vision-dependent functioning in glaucoma in south India. This study also found that I-CAARV task performance was strongly correlated with contrast sensitivity and suggests that performance-based and patient-reported outcomes are related but distinct measures of the impact of glaucoma on functioning and vision-related quality of life. Future studies are needed to determine the sensitivity of the I-CAARV to detect changes due to disease progression that are relevant to functioning and vision-related quality of life.

Associations of subjective and objective clinical outcomes of visual functions with quality of life in Chinese glaucoma patients: a cross-sectional study

BACKGROUND

The cost of managing a chronic disease like glaucoma is quite large. A convenient and economical monitoring tool like self-reported measures of Quality of Life (QoL) could have the potential to significantly reduce the health economic burden of this disease. However, evidence about whether QoL can effectively reflect both subjective and objective clinical outcomes of visual functions in glaucoma patients is lacking. In this paper, we examined the relationships between both subjective and objective visual functions and QoL in glaucoma patients.

METHODS

This cross-sectional study enrolled 107 patients with a broad range of glaucomatous visual function loss. Subjective visual function loss was assessed using tests of visual acuity (VA), contrast sensitivity (CS) and visual field (VF). Evaluation of objective visual function was performed using pattern visual evoked potentials (PVEP). National Eye Institute Visual Function Questionnaire 25 (NEI VFQ-25) and Glaucoma Quality of Life-15 (GQL-15) were used to measure QoL. Uni- and multivariable linear regression analyses were performed to investigate the associations between all the clinical variables with Rasch-calibrated QoL scores.

RESULTS

Univariate analysis revealed that worse Rasch-calibrated NEI VFQ and GQL scores were associated with poorer VA and CS in both the better eye (BE) and the worse eye (WE), and with worse VF mean deviation, VF pattern standard deviation and PVEP latency and amplitude in 15 min check size in the WE (P < 0.05). Multivariable linear regression analysis revealed that, after adjusting for age, gender, duration of glaucoma, glaucoma severity and glaucoma type, Rasch-calibrated NEI VFQ-25 person measure scores were significantly associated with PVEP latency in 15 min check size [β = - 0.347, 95% CI: (- 0.618, - 0.118), P = 0.001] in the WE; Rasch-calibrated GQL-15 person measure scores were significantly associated with PVEP amplitude in 15 min check size [β = - 0.338, 95% CI: (- 0.588, - 0.108), P < 0.001] in the WE.

CONCLUSIONS

Self-reported measures of QoL could be supplemental tools for assessing both subjective and objective visual functions in glaucoma patients.

Comparison of contrast sensitivity in macaque monkeys and humans

Contrast sensitivity functions reveal information about a subject's overall visual ability and have been investigated in several species of nonhuman primates (NHPs) with experimentally induced amblyopia and glaucoma. However, there are no published studies comparing contrast sensitivity functions across these species of normal NHPs. The purpose of this investigation was to compare contrast sensitivity across these primates to determine whether they are similar. Ten normal humans and eight normal NHPs (Macaca fascicularis) took part in this project. Previously published data from Macaca mulatta and Macaca nemestrina were also compared. Threshold was operationally defined as two misses in a row for a descending method of limits. A similar paradigm was used for the humans except that the descending method of limits was combined with a spatial, two-alternative forced choice (2-AFC) technique. The contrast sensitivity functions were fit with a double exponential function. The averaged peak contrast sensitivity, peak spatial frequency, acuity, and area under the curve for the humans were 268.9, 3.40 cpd, 27.3 cpd, and 2345.4 and for the Macaca fascicularis were 99.2, 3.93 cpd, 26.1 cpd, and 980.9. A two-sample t-test indicated that the peak contrast sensitivities (P = 0.001) and areas under the curve (P = 0.010) were significantly different. The peak spatial frequencies (P = 0.150) and the extrapolated visual acuities (P = 0.763) were not different. The contrast sensitivities for the Macaca fascicularis, Macaca mulatta, and Macaca nemestrina were qualitatively and quantitatively similar. The contrast sensitivity functions for the NHPs had lower peak contrast sensitivities and areas under the curve than the humans. Even though different methods have been used to measure contrast sensitivity in different species of NHP, the functions are similar. The contrast sensitivity differences and similarities between humans and NHPs need to be considered when using NHPs to study human disease.