Retinal Vessel Diameter: 1. Comparison of Normal and Glaucoma Eyes

ABSTRACT

Narrowing of the retinal vessels in chronic glaucoma has been recognized only recently. We performed this study to evaluate the vessel diameter in normal and glaucoma eyes, addressing whether the retinal vessel diameters differ with the degree of glaucomatous optic nerve damage. The diameters of the superior temporal and inferior temporal retinal artery and vein were measured at the optic disc border from optic disc photographs of 234 eyes of 141 patients with primary open-angle glaucoma and 139 eyes of 86 normal subjects. The photographic magnification was corrected according to Littmanns method. Only one eye per patient and subject was taken for statistical analysis. According to the neuroretinal rim/disc area ratio, the glaucoma group was divided into four stages(early; more than 0.61, medium; 0.60~0.41, advanced; 0.40~0.21, far advanced; less than 0.20). In the normal group the diameter of the inferior temporal vein(0.130+/-0.020mm) was the largest, followed by the superior temporal vein(0.117+/-0.017mm), the inferior temporal artery(0.102+/-0.016mm), finally the superior temporal artery(0.093+/-0.012mm). The retinal vessel diameter decreased significantly with decreasing of the neuroretinal rim/disc area ratio. In the glaucomatous eyes as compared to the normal eyes, the diameters of the inferior temporal and superior temporal retinal artery were significantly smaller at the early and medium stages(p<0.03, p<0.02, respectively). Whereas both inferior temporal and superior temporal retinal vein diameters were significantly samller at the far advanced stage(p=0.01, p=0.005, respectively). The results indicate that generalized reduction of the retinal vessel diameter throughout the retina is related to the severity of glaucoma. From a diagnostic point of view, evaluation of artery diameter rather than vein diameter may be helpful for the differentiation between normal and glaucomatous eyes.