Active Learning to Characterize the Full Contrast Sensitivity Function in Cataracts

Impaired Visual Function in Posterior Vitreous Detachment Assessed With the Active-Learning Quantitative Contrast Sensitivity Function Test

Introduction: To investigate whether there is visual function impairment in patients with posterior vitreous detachment (PVD) using the active-learning quantitative contrast sensitivity function test. Methods: In this cross-sectional study, contrast sensitivity was measured in eyes with PVD and eyes without PVD using the quantitative contrast sensitivity function algorithm on the Adaptive Sensory Technology platform. Outcomes included the area under the log contrast sensitivity function curve, contrast acuity, and contrast sensitivity thresholds at 1 to 18 cycles per degree (cpd). Snellen visual acuity (VA) was also measured. Mixed-effects multiple linear regression analyses were performed to evaluate the association between the presence of PVD and visual function, controlling for age and lens status. Results: The cohort comprised 232 healthy eyes of 205 participants; of these, 80 eyes of 69 patients had PVD. There was no significant association between VA and PVD presence. However, PVD was significantly associated with decreased contrast sensitivity thresholds at 1.5 cpd (β, -0.058; P = .003) and 3 cpd (β, -0.067; P = .004). Contrast sensitivity thresholds at lower (1 cpd) or higher (6, 12, 18 cpd) spatial frequencies did not significantly correlate with PVD presence. Even in the subgroup of symptomatic PVD eyes, VA was not significantly decreased, while quantitative contrast sensitivity function outcomes showed visual function deficits at low spatial frequencies (1.5 cpd and 3 cpd). Conclusions: Contrast sensitivity measured with the quantitative contrast sensitivity function test showed visual function deficits in eyes with PVD that would have been missed with VA testing alone. Incorporating this test in the retina clinic might offer a more comprehensive functional assessment of eyes with PVD, serving as an adjunct outcome metric in clinical decision-making.

Contrast Sensitivity Better Reflects Wide-Field Swept-Source Optical Coherence Tomography Angiography Vascular Metrics Among Healthy Eyes Compared to Visual Acuity

BACKGROUND AND OBJECTIVE

To evaluate the association between widefield swept-source optical coherence tomography angiography (WF SS-OCTA) and visual function in healthy eyes.

PATIENTS AND METHODS

Fifty-seven eyes of 45 patients were evaluated with visual acuity (VA), contrast sensitivity (CS), and WF SS-OCTA (3 × 3, 6 × 6, and 12 × 12 mm images) on the same day. Mixed-effects multivariable regression analyses were performed.

RESULTS

Contrast sensitivity metrics, including CS between 6 to 18 cycles per degree (cpd) and area under the logarithm CS function, were significantly associated with vessel density (VD) and vessel skeletonized density (VSD), whereas VA was not. The largest effect size was between CS at 18 cpd and VD (β = 0.41, P = 0.007) and VSD (β = 0.42, P = 0.006) on 12 × 12 mm images.

CONCLUSIONS

Reduced VSD and VD on WF SSOCTA was significantly associated with decreased CS, whereas VA was not. These results suggest CS could serve as a screening tool for early stage retinal and neurologic disorders. [Ophthalmic Surg Lasers Imaging Retina 2024;55:494-502.].

Subgroup Analysis from a Phase 1/2 Randomized Clinical Trial of 2.6% EDTA Ophthalmic Solution in Patients with Age-Related Cataract

PURPOSE

To explore the efficacy of topical 2.6% EDTA ophthalmic solution (C-KAD) as a treatment to improve visual function for the subgroup of patients with loss of contrast sensitivity (CS) due to early-stage age-related cataract.

DESIGN

Subgroup analysis of randomized, double-blinded, placebo-controlled, multicenter phase 1/2 clinical trial data.

METHODS

Both eyes of subjects in the intent-to-treat population, with mesopic CS scores between 1 and 7 grating patches (range 0-9, each patch representing 0.15 logCS), at baseline in all five frequencies, were included. The proportion of eyes with clinically significant mesopic CS improvement and mean changes in mesopic CS at spatial frequencies between 1.5 to 18 cycles per degree (cpd), and summary metrics of area under the log CS function (AULCSF), were analyzed. Other exploratory outcomes analyzed included best-corrected visual acuity (BCVA) and lens density for a smaller subgroup of eyes for which Scheimpflug images were available.

RESULTS

Forty-one subject eyes were included in the subgroup analysis (C-KAD n = 21, placebo n = 20). The primary endpoint of the proportion of eyes with mesopic CS improvements ≥ 0.30 logCS (equivalent to 100% CS improvement) in at least two of the five spatial frequencies was significantly greater for C-KAD (66.7% versus 35.0% for placebo, P = .043) at Day 120. C-KAD met the primary protocol endpoint in this subgroup analysis. The proportion of eyes achieving ≥ 0.30 logCS improvement (mesopic) as measured in AULCSF was also significantly greater for C-KAD, with 42.9% compared to 15.0% for placebo (P = .050) at Day 120. The mean change in AULCSF (mesopic) was significantly larger for C-KAD, with 0.25 logCS improvement, versus placebo with 0.06 logCS improvement (P = .020) at Day 120. C-KAD also showed significant mesopic CS improvements at spatial frequencies 3 and 6 cpd, with 0.28 logCS (P = .004) and 0.31 logCS (P = .047) versus placebo at Day 120. Positive BCVA trends and statistical significance in lens density were also observed.

CONCLUSIONS

A significant treatment effect of C-KAD in visual function and vision quality was observed consistently. These promising results suggest a novel, non-invasive pharmacological treatment to improve vision in patients with early-stage cataract.

Evaluation of the SpotChecks contrast sensitivity test in healthy adults

PURPOSE

SpotChecks is a new contrast sensitivity (CS) test designed for self-monitoring of vision. This study assessed the test-retest repeatability of take-home SpotChecks, in-office SpotChecks and near Pelli-Robson charts in healthy adults.

METHODS

One eye of 61 healthy adults with near visual acuity (VA) of 6/9 or better (age range 22-84, mean 49 [18] years) was tested during two office visits (mean 10 [8] days apart). Each visit included high-contrast VA, then 12 randomly ordered CS tests (6 different SpotChecks and 6 different Pelli-Robson) under the same lighting (luminance 110 cd/m2), all at near in the same eye with habitual correction. The same eye was self-tested with take-home SpotChecks once a day on 6 days between the office visits. SpotChecks was scored by the logCS at the highest line with ≥2 errors. Pelli-Robson was scored by [0.05 × number of letters read correctly - 0.15]. Repeatability of logCS was defined as 1.962 $$ \sqrt{2} $$ Sw, Sw representing within-subject standard deviation. Comparison for repeatability was performed with Bootstrap hypothesis test.

RESULTS

SpotChecks and Pelli-Robson showed similar intra-session or inter-visit repeatability (p = 0.14-0.81). Inter-day repeatability for take-home SpotChecks was 0.18 logCS, the same as that from the first measurements of two office visits with SpotChecks or Pelli-Robson. Inter-visit repeatability improved to 0.15 by using the average of two repeated measurements for SpotChecks (p = 0.02) or three repeated measurements for Pelli-Robson (p = 0.04). Age showed a small effect on logCS (-0.015/decade, p = 0.02) for both SpotChecks and Pelli-Robson. Mean logCS was 0.05 lower in those ≥50 years (SpotChecks 1.84 [0.10] and Pelli-Robson 1.77 [0.10]) compared with those <50 years of age (SpotChecks 1.89 [0.07] and Pelli-Robson 1.83 [0.07]).

CONCLUSIONS

SpotChecks showed good repeatability with take-home and in-office testing in healthy adults, making it a promising tool for monitoring disease progression at home.

Towards the validation of quantitative contrast sensitivity as a clinical endpoint: correlations with vision-related quality of life in bilateral AMD

AIM

To investigate if active learning of contrast sensitivity (CS) in bilateral age-related macular degeneration (AMD) correlates better than visual acuity (VA) with vision-related quality of life (VRQoL) using factor analysis-calibrated National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25).

METHODS

Prospective cross-sectional observational study in 93 patients (186 eyes) with bilateral AMD. CS was measured in one eye at a time with the quantitative CS function (qCSF) method (Adaptive Sensory Technology). Same-day VRQoL was assessed with factor analysis-calibrated NEI VFQ-25 visual function and socioemotional scales. Mixed-effects multiple linear regression analyses evaluated the associations of the qCSF outcomes and VA with the NEI VFQ-25 scales. A subgroup analysis on patients with AMD with VA more than 20/25 in both eyes was performed.

RESULTS

Compared with VA, CS outcomes were associated with larger effect on both visual function scale (standardised beta coefficients (β*) for area under the logarithm of CSF (AULCSF) curve and CS thresholds at 1.5, 3 and 6 cycles per degree (cpd): β*=0.50, 0.48, 0.52, 0.46, all p<0.001, respectively, vs β*=-0.45 for VA, all p<0.001) and socioemotional scale (β* for AULCSF and CS threshold at 6 cpd: β*=0.44, 0.44 vs β*=-0.42 for VA, all p<0.001). In patients with AMD with VA more than 20/25 in both eyes (N=20), both VFQ-25 scales and all CS outcomes were significantly reduced.

CONCLUSIONS

qCSF-measured CS strongly correlates with patient-reported VRQoL in bilateral AMD, even stronger than VA does. This study further validates qCSF-measured CS as a promising functional endpoint for future clinical trials in AMD.

Quantitative Contrast Sensitivity Function and the Effect of Aging in Healthy Adult Eyes: A Normative Database

BACKGROUND AND OBJECTIVE

We sought to establish normative quantitative contrast sensitivity function (qCSF) values in healthy adult eyes and investigate the effect of age on qCSF.

PATIENTS AND METHODS

Healthy eyes underwent qCSF testing (adaptive sensory technology) and Snellen's visual acuity (VA). Descriptive statistics and mixed-effects multivariable linear regressions were evaluated.

RESULTS

A total of 334 eyes (290 patients) with median age 61 years (range 21 to 88) had qCSF values as follows: area under the log contrast sensitivity function curve: 1.18; contrast acuity: 1.32; contrast sensitivity (CS) at 1 cycle per degree (cpd): 1.32; CS at 1.5 cpd: 1.37; CS at 3 cpd: 1.38; CS at 6 cpd: 1.20; CS at 12 cpd: 0.69; CS at 18 cpd: 0.22. Linear reductions in qCSF values per decade of age ranged from -0.02 to -0.07 vs 0.01 for visual acuity (VA). Age had a greater effect on the majority of qCSF values than VA (beta standardized regression coefficient ranged from -0.309 to -0.141 for qCSF values vs 0.177 for VA).

CONCLUSIONS

We herein establish a normative database for qCSF and quantify the effect of age on qCSF values, adding evidence towards the validation of qCSF as a clinical endpoint. [Ophthalmic Surg Lasers Imaging Retina 2024;55:212-219.].

Test-retest repeatability and agreement of the quantitative contrast sensitivity function test: towards the validation of a new clinical endpoint

PURPOSE

The purpose of this study is to investigate test-retest reliability and agreement of the quantitative contrast sensitivity function test (qCSF) in the retina clinic.

METHODS

A total of 121 right eyes of 121 patients were tested and consecutively re-tested with qCSF in the retina clinic. Outcomes included area under the logarithm of contrast sensitivity function curve (AULCSF), contrast acuity, and contrast sensitivity thresholds at 1-18 cycles per degree (cpd). Test-retest means were compared with paired t-test, variability was compared with the Brown-Forsythe test, and intraclass correlation coefficient (ICC) and Bland Altman plots evaluated reliability and agreement.

RESULTS

Mean test-retest differences for all qCSF metrics ranged from 0.02 to 0.05 log units without statistically significant differences in variability. Standard deviations ranged from 0.08 to 0.14. Coefficients of repeatability ranged from 0.16 to 0.27 log units. ICC > 0.9 for all metrics except 1cpd (ICC = 0.84, all p < 0.001); AULCSF ICC = 0.971.

CONCLUSION

qCSF-measured contrast sensitivity shows great test-retest repeatability and agreement in the retina clinic.

Structure-function associations between contrast sensitivity and widefield swept-source optical coherence tomography angiography in diabetic macular edema

PURPOSE

To evaluate the relationship between contrast sensitivity (CS) and widefield swept-source optical coherence tomography angiography (WF SS-OCTA) vascular metrics in diabetic macular edema (DME) was the purpose.

METHODS

This prospectively enrolled cross-sectional observational study included 61 eyes of 48 patients that were tested with the quantitative CS function (qCSF) test on the same day as imaging with WF SS-OCTA (PLEX® Elite 9000, Carl Zeiss Meditec) 3 × 3, 6 × 6, and 12 × 12 mm scans. Outcomes included visual acuity (VA) and multiple qCSF metrics. Vascular metrics included vessel density (VD) and vessel skeletonized density (VSD) in the superficial (SCP) and deep capillary plexus (DCP) and whole retina (WR) and foveal avascular zone (FAZ) parameters. Mixed effects multivariable linear regression models controlling for age, lens status, and diabetic retinopathy stage were performed. Standardized beta coefficients were calculated by refitting the standardized data.

RESULTS

SS-OCTA metrics had a significant association with CS and VA. The effect size of OCTA metrics was larger on CS compared to VA. For example, the standardized beta coefficients for VSD and CS at 3 cpd (βSCP = 0.76, βDCP = 0.71, βWR = 0.72, p < 0.001) were larger than those for VA (βSCP =  - 0.55, p < 0.001; βDCP =  - 0.43, p = 0.004; βWR =  - 0.50, p < 0.001). On 6 × 6 mm images, AULCSF, CS at 3 cpd, and CS at 6 cpd were significantly associated with VD and VSD in all three slab types (SCP, DCP, and WR), while VA was not.

CONCLUSION

Structure-function associations in patients with DME leveraging the qCSF device suggest microvascular changes on WF SS-OCTA are associated with larger changes in contrast sensitivity than VA.