Abstract
Purpose:
To assess the spatial configuration of the main arteries and veins of the temporal arcade in genetically diagnosed subjects with albinism and normal subjects and to assess its relationship to visual acuity and spherical equivalent. Assessment of the angle with which these vessels leave the optic nerve has been used in evaluation of macular structure.
Methods:
Fundus photographs of the posterior pole (30° field of view) including the main retinal blood vessels were taken using a Topcon Fundus Camera (TRCNW6S) in subjects with albinism (n=16) and age similar controls (n=18). Measurements of the angle between the main inferior and superior vein and the main inferior and superior artery were made using a custom vessel segmentation program at a number of eccentricities extending for two disk diameters from the center of the optic nerve head. Visual acuity and spherical equivalent were determined for each subject.
Results:
For the arteries, angle varied significantly with group (F= 8.79; df 1,524, p<0.01) and eccentricity (F=38.1, df 15, 524, p<0.01). For the veins, angle also varied significantly with group (F= 10.4; df 1,532, p<0.01) and eccentricity (F=15.5, df 15, 532, p<0.01). The angle between superior and inferior veins was significantly smaller in controls than in subjects with albinism. Separation of artery/vein pairs was larger in controls than in the albino subjects (14 degrees vs 3 degrees). Visual acuity was significantly poorer in the albino subjects (p<0.001). Spherical equivalent of albino and control subjects was similar. Neither visual acuity nor spherical equivalent was significantly related to blood vessel angle.
Conclusions:
Differences in the spatial configuration of retinal arteries and veins may be a consequence of the altered retinal development that leads to abnormal foveal pit formation in albinism.
Keywords: 698 retinal development