Purpose:
To investigate the relationship between laser-induced resolution of drusen and choroidal blood flow changes in the Complication of Age-Related Macular Degeneration Prevention trial (CAPT).
Methods:
We investigated 23 CAPT patients (14 female, mean (SD) age: 71.4 (4.95)) with ≥ 10 bilateral drusen (>125µ) who received photocoagulation in one randomly selected eye at the University of Pennsylvania. Fundus photographs were obtained and laser Doppler flowmetry (Oculix) was used to assess relative foveolar choroidal blood velocity (ChBvel), volume (ChBVol), and flow (ChBFlow) in both eyes prior to laser administration, and again at 24 to 36 months (average: 28 months) after laser treatment. Trained readers at the CAPT Reading Center graded fundus photographs obtained at baseline, 24 and 36 months visits. The photographs were evaluated for percent area of baseline drusen reduction within 3000 µ of the fovea. Treated eyes were divided into two groups according to the resolution of drusen. In comparison to baseline drusen, group 1 showed ≥ 50% reduction (N=9) and group 2 showed < 50% reduction (N=14). Choroidal blood flow changes from baseline were compared between these two groups. Analysis of all data was performed in a masked fashion. Circulatory measurements are shown as mean (SE) in arbitrary units (AU).
Results:
At 24 to 36 months after laser photocoagulation, eyes with more baseline drusen resolution had significantly larger increases in ChBVel, ChBVol and ChBFlow than those with less drusen resolution.Multivariate analysis adjusted by age and IOP showed similar results for ChBVel (P =0.04), ChBVol (P =0.01), and ChBFlow (P =0.003).
Conclusions:
Eyes that show more drusen reduction following laser treatment have larger increases in choroidal circulatory parameters suggesting that circulatory increases may play a role in the mechanisms that results in the resolution of drusen.
Keywords: age-related macular degeneration • laser • drusen