Ocular blood flow velocity in age-related macular degeneration

Changes in the structure of the ocular blood vessels associated with age-related macular degeneration (AMD) have been described in some detail, but comparatively little is known of the concomitant circulatory changes. The goal of this study is to evaluate changes in the ocular circulation that may be associated with AMD.

Ocular blood flow velocities and vessel pulsatilities were measured in volunteers with and without AMD using a color Doppler imaging unit. Spectral analyses were recorded from the ophthalmic artery, central retinal artery and vein, the temporal and nasal short posterior ciliary arteries, and the four vortex veins.

Adjusting for age, pulsatility indices of all arteries were higher in subjects with AMD (central retinal artery [P = 0.02]; temporal and nasal short posterior ciliary arteries [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.

The combination of increased pulsatility and decreased velocity of the short posterior ciliary arteries, observed in the presence of AMD, are interpreted as evidence of increased vascular resistance. The clinical signs of AMD may be related to degradation of the metabolic transport function of the retinal pigment epithelium, resulting from impaired choroidal perfusion.