Contrast Sensitivity Function in Non-Neovascular Age-related Macular Degeneration Measured with Active Learning

Abstract

Purpose : Compared to visual acuity, contrast sensitivity function (CSF) better correlates with vision-related quality of life and subjectively perceived visual impairment, and may be affected earlier in the course of age-related macular degeneration (AMD). Inherent imperfections of the existing contrast tests have prevented its adoption in the clinical practice. Our aim is to characterize CSF in different stages of non-neovascular AMD (nnAMD) compared to healthy controls employing a novel active learning quick CSF (qCSF) method.

Methods : This prospective cross-sectional study included nnAMD patients graded by consensus grading (clinical exam, color fundus photos, and OCT) and healthy controls. Contrast was measured using the Manifold Contrast Vision Meter (Adaptive Sensory Technology, San Diego, CA). Outcomes included Area under the Log CSF (AULCSF), contrast sensitivity (CS) thresholds at 1, 1.5, 3, 6, 12, and 18 cycles per degree (cpd). Mixed-model multiple linear regression analyses were performed to evaluate the association between presence and stage of nnAMD (vs controls) and the CSF outcome measures.

Results : A total of 363 eyes were included, 249 nnAMD eyes (68 Early, 154 Intermediate, 27 Advanced) and 114 control eyes. Mean BCVA for controls was 0.020 versus 0.040 in early (P> 0.05), 0.140 in intermediate (P= 0.002) and 0.550 in advanced nnAMD eyes (P< 0.001). When controlling for age and lens status, early nnAMD was significantly associated with reduced CSF thresholds at low spatial frequencies (1, 1.5, 3 cpd) (β= -0.09, β= -0.09, and β= -0.11, respectively, all P< 0.01) compared to controls, despite no difference in BCVA. Intermediate and advanced nnAMD were significantly associated with reduced CSF at 1, 1.5, 3, 6 and 12 cpd and reduced AULCSF (all P< 0.01). On trend analysis, nnAMD progression was associated with corresponding significant progressive decline in AULCSF (Early β=-0.06, Intermediate β=-0.18, Advanced β=-0.64 vs controls)(Figure 1).

Conclusions : Early nnAMD was associated with reduced CSF compared to controls as measured by the novel qCSF method, despite no difference in BCVA. Worsening nnAMD stages were associated with a progressive decline in AULCSF. The qCSF may emerge as a promising visual function endpoint in the routine clinical practice and future nnAMD clinical trials.

This is a 2021 ARVO Annual Meeting abstract.

 

Contrast sensitivity fucntion in AMD stages vs controls as measured by the qCSF method.