Towards an Early Scale for Dry AMD Based on Clinical Observation

Abstract

Purpose : Early detection and treatment of AMD requires a clear understanding of the early progress of the disease. Clinical observation of subtle retinal pigment abnormalities suggests that this stage is not fully characterized by commonly used scales. We investigated a group of older subjects both with and without early fundus changes (AREDs 0). Subgroup 0B was defined as subjects presenting with subtle observed pigment changes (clumping, mottling or surface irregularities described as changes in patina) and/or small drusen. Subgroup 0A was defined by subjects with no visible changes. The purpose of the study was to investigate whether these early changes corresponded to changes in visual function. Subjects were classified using color fundus photography and underwent a battery of visual psychophysical tests.

Methods : Subjects were required to have BCVA of 20/25 or better and to have had no previous diagnosis of AMD or other retinal disease. All subjects underwent color fundus photography and OCT. A retina specialist graded all photos using 5x magnification for possible anomalies of macular pigment and small drusen. Subjects with fundus changes of AREDS 1 or greater were excluded. This defined a group of 19 subjects (mean age 75.4 ± 4.4) with early fundus changes (0B) and a control group of 15 subjects (mean age 74.8 ± 5.2) (0A). All subjects were then tested for ETDRS BCVA, Pelli-Robson contrast sensitivity, variable contrast flicker (VCF) sensitivity, and reading rate using both MNRead and low luminance reading on a tablet.

Results : BCVA for 0A subjects was 0.0 ± 0.11 and 0.078 ± 0.17 for 0B (p=0.063). Mean Pelli-Robson contrast sensitivity was 1.75 ± 0.29 for the 0A group and 1.78 ± 0.17 for the 0B group (p=0.73). VCF flicker sensitivity threshold was 0.47 ± 0.25 (0A) and 0.43 ± 0.22 (0B) (p=0.64). Reading speed using MNRead (words per minute) was 214 ± 47.4 (0A) and 210 ± 64.7 (0B) (p=0.17). Low luminance tablet reading (words per minute) was 137 ± 71.8 (0A) and 151 ± 39.4 (0B) (p=0.5).

Conclusions : A panel of psychophysical tests did not demonstrate significant differences between subjects with and without early fundus changes.

This is a 2020 ARVO Annual Meeting abstract.