Abstract
Purpose :
Cone dysfunction is a known pathological process in age-related macular degeneration (AMD). However, it is unclear if blue color sensitivity is affected in early stages of AMD. In this study, a new blue color sensitivity test was used to assess visual function in non-advanced AMD subjects.
Methods :
Subjects with non-advanced AMD N=14 (grade 1 to 4 on AREDS simplified scale) and normal controls N=25 (AREDS grade 0) with best visual acuity (VA) 20/25 or better during their baseline visit were included. Color contrast sensitivity was tested using a computerized system. Testing was done for the study eye, with best correction in place and non-tested eye occluded. The stimulus was a blue Landolt C target presented on an equiluminant background. Two background levels of high mesopic and low mesopic levels were used. For each background, the stimulus was initially presented at high contrast level which then progressively reduced in contrast. Threshold was determined based on a stair-case method. For each background, the minimum contrast needed to correctly identify the stimulus orientation was recorded as the threshold. Subjects also underwent other common visual tests such as standard ETDRS VA, and low luminance 2.0 neutral density (ND) ETDRS VA.
Results :
Blue color sensitivity showed worsening in the non-advanced AMD group compared to age-matched normal group, for both high mesopic and low mesopic levels, although the results did not reach statistical significance. Mean threshold in the high mesopic background was 0.14±0.08 in AMD group and 0.11±0.06 in normal group (p=0.12). Mean threshold in the low mesopic background was 0.29±0.15 in the AMD group and 0.22±0.08 in the normal group (p=0.09). Both normal subjects and non-advanced AMD subjects showed reduced sensitivity in low mesopic testing condition compared to high mesopic testing. No difference between the two groups were found using other common tests such as standard ETDRS VA and 2.0 ETDRS VA.
Conclusions :
Blue color contrast testing could capture subtle color contrast deficits in early/intermediate stages of AMD and may be useful test for assessing color function in AMD studies.
This is a 2021 ARVO Annual Meeting abstract.