Vision function differs with retinal characteristics in AMD: large drusen with and without pigment abnormalities.

Purpose : Drusen size and pigmentary changes are factors related to the risk of development of advanced AMD. Our goal was to determine whether vision function is related to the presence of pigment abnormalities in eyes with large drusen.

Methods : Best-corrected vision was measured in each eye in individuals diagnosed with early to intermediate AMD as part of a larger study (Lott et al, ARVO 2016). Data from 39 individuals (dominant eye at near) with multiple large drusen (≥125 microns) in the central 10 degrees of the macula are included. Two subgroups were formed on the basis of the presence (LDwP group, n=16) or absence (LDOnly group, n=23) of accompanying pigment abnormalities (mean age 77.9±10.5 and 74.7±11.2 years, respectively). Vision measures included high contrast visual acuity (HCVA, SKILL light chart), low contrast low luminance acuity (SKILL Dark chart), contrast sensitivity (MARS chart), color vision (Adams desaturated D-15 color arrangement test), and shape discrimination hyperacuity (SDH- threshold for the identification of a distorted circle from among 3 circles; Wang et al., IOVS, 2013). SKILL score (the difference between logMAR acuity on the light and dark charts of the SKILL Card) was calculated. One-tailed t-tests were used to determine whether vision function is poorer in eyes with large drusen and pigment abnormalities than in eyes with large drusen alone. With Bonferroni correction, p≤ 0.01 is statistically significant.

Results : Mean HCVA was fairly good and did not differ between groups (logMAR = 0.10 or 20/25 for both). MARS log contrast sensitivity was also very similar between the LDwP and LDonly groups (1.59, vs 1.62; p=0.18). SKILL score (0.64 vs.0.57, p=0.045) and color confusion score (62.4 vs. 43.1, p=0.10) were both slightly, but not significantly, poorer in eyes with pigment abnormalities. Only SDH differed significantly between groups (-0.44 vs -0.61, p=0.007), with higher thresholds in the group with pigment abnormalities than those with large drusen only.

Conclusions : Though standard visual acuity does not distinguish groups with different risk characteristics for developing advanced AMD, in eyes with large drusen, shape discrimination hyperacuity thresholds are further elevated in the presence of pigment abnormalities.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.