OCULAR BLOOD-FLOW VELOCITY IN AGE-RELATED MACULAR DEGENERATION

Background: Changes in the structure of the ocular blood vessels assoc iated with age-related macular degeneration (AMD) have been described in some detail, but comparatively little is known of the concomitant c irculatory changes. The goal of this study is to evaluate changes in t he ocular circulation that may be associated with AMD. Methods: Ocular blood flow velocities and vessel pulsatilities were measured in volun teers with and without AMD using a color Doppler imaging unit. Spectra l analyses were recorded from the ophthalmic artery, central retinal a rtery and vein, the temporal and nasal short posterior ciliary arterie s, and the four vortex veins. Results: Adjusting for age, pulsatility indices of all arteries were higher in subjects with AMD (central reti nal artery [P = 0.02]; temporal and nasal short posterior ciliary arte ries [P = 0.06 and 0.002, respectively]; and ophthalmic artery [P = 0. 24]). End-diastolic blood flow velocity of the short posterior ciliary arteries tended to decrease in the presence of AMD. Conclusions: The combination of increased pulsatility and decreased velocity of the sho rt posterior ciliary arteries, observed in the presence of AMD, are in terpreted as evidence of increased vascular resistance. The clinical s igns of AMD may be related to degradation of the metabolic transport f unction of the retinal pigment epithelium, resulting from impaired cho roidal perfusion.