Scanning laser Doppler flowmeter study of retinal and optic disk blood flow in glaucomatous patients

PURPOSE: To examine blood flow in the retina and optic nerve head of patients with primary open-angle glaucoma. METHODS: Retinal and optic nerve head blood flow of glaucoma patients and control subjects of similar age and gender were measured in arbitrary units with the Heidelberg Retina Flowmeter, a scanning laser Doppler flowmeter (Heidelberg Engineering, Heidelberg, Germany). A total of 33 glaucoma patients and 29 control subjects were included in this study. Microvascular blood volume, flow, and velocity were analyzed in four areas of the retina approximately 100 μm from the edge of the optic disk (two temporal, one superior, and one inferior), in one area of the neuroretinal rim, and in the lamina cribrosa. RESULTS: The glaucoma patients had significantly decreased blood volume, flow, and velocity in one temporal retinal area (P < .006) and in blood volume in the inferior retinal area (P = .04). They also had significantly decreased blood volume, flow, and velocity in the lamina cribrosa (P < .0004), which also had more areas the investigators judged to be avascular compared to control subjects (P < .0001). No differences between glaucoma and control subjects in the blood flow measurements of the neuroretinal rim were found. CONCLUSION: These findings suggest that glaucoma patients tend to have less blood volume, flow, and velocity in the lamina cribrosa and upper temporal peripapillary retina. The temporal area below the horizontal, corresponding to the papillomacular bundle, did not show this difference. The findings may be significant in the pathogenesis of primary open-angle glaucoma.