Abstract
Purpose: :
To investigate the choroidal circulation in AMD patients with geographic atrophy (GA).
Methods: :
We conducted a cross-sectional study of 256 eyes of 186 patients with age-related macular degeneration. Presence of GA was determined from color fundus photographs by trained masked graders at the Scheie Image Reading Center within a distance of 500 microns from the center of the fovea. 16 eyes had GA and 240 eyes had no signs of GA within 500 microns. Relative choroidal blood velocity (ChBVel), volume (ChBVol) and flow (ChBFlow) were measured with laser Doppler flowmetry (Oculix instrument). All study eyes had visual acuity of 20/40 or better and good fixation. Eyes with choroidal neovascularization (CNV) or other ocular pathology were excluded from the study. Univariate analyses and multivariate linear regression analyses were carried out with adjustments for the following statistically significant covariates. Perfusion pressure (PP), mean blood pressure, systolic and diastolic blood pressure for ChBVel. Age, intraocular pressure, spherical equivalent, hypertension and smoking status for ChBVol. Age, spherical equivalent and hypertension for ChBFlow. The correlation between paired eyes from the same subject was adjusted by using the generalized estimating equations (GEE). Results of choroidal circulatory parameters are shown in arbitrary units (AU).
Results: :
Average ChBVel was significantly lower in the group of 16 eyes with GA 0.34 ± 0.01 AU (± SE) than in the group of 240 eyes that did not have GA 0.38 ± 0.01 AU (p=0.006, univariate analysis). There were no statistically significant differences between eyes with GA and eyes without GA in average ChBVol (0.23± 0.02 AU and 0.23± 0.01 AU, p=0.90) and ChBFlow (6.50±0.44 AU and 7.39±0.26 AU, p=0.07). Multivariate analyses showed very similar results.
Conclusions: :
AMD eyes with GA show a 10% lower average ChBVel than those without GA. Although the average ChBFlow is also reduced by 10% in eyes with GA, the difference is not statistically significant. These findings are in contrast to our previous findings in AMD eyes that develop CNV, where we found significant decreases in ChBFlow caused mainly by changes in ChBVol.
Keywords: age-related macular degeneration • blood supply • drusen