Visual Function Measures in Early and Intermediate Age-Related Macular Degeneration

Abstract

Purpose

The objectives of this study were to evaluate 1) the feasibility of performing computerized tests of low luminance visual acuity (LLVA), cone-specific contrast (CCT), contrast sensitivity, and microperimetry and 2) the test-retest repeatability of these outcomes in dry age-related macular degeneration (AMD).

Methods

This prospective study enrolled 30 subjects at a single site (8 controls, 8 early AMD and 12 intermediate AMD). Subjects underwent LLVA, contrast sensitivity, CCT, and microperimetry with eye tracking. Low luminance deficit (LLD) was defined as BCVA minus LLVA in EDTRS letters. Follow-up testing was administered at approximately one month.

Results

There was high test-retest repeatability at one month for all visual function metrics (intraclass correlations, ICC>0.7) except log contrast sensitivity (ICC 0.6). Compared to controls, patients with intermediate AMD showed significant deficits on BCVA, LLVA, LLD, percent reduced threshold on microperimetry, and red CCT (p<0.05), but not on contrast sensitivity, green and blue CCT.

Conclusions

This pilot study supports the feasibility and reliability of employing LLVA, microperimetry and CCT in early dry AMD. Our data suggests these measures can be employed as alternative future clinical trial endpoints. A larger prospective natural history study of alternative visual function measures in dry AMD is warranted.