Abstract
flow appear to be very common characteristics associated with the onset and progression of several ocular diseases including age-related macular degeneration, the retinopathy of diabetes, open angle glaucoma, retinal artery and central vein occlusion, and detachment of the retina. The loss of vascular autoregulation appears to be a consequence of a relative ocular ischemia and reflects a diminished capacity to minimize changes in intraocular pressure (IOP) and ocular blood flow. Based on observations in healthy eyes of subjects who have suffered a stenosis of the internal carotid artery, the maximal capacity of the blood flow autoregulation is found to be of the order of 400–500 μ l min −1 . This increased blood flow occurs following unilateral occlusion of the internal carotid artery and returns to normal following successful surgical endarterectomy (see Sect. 3). An abnormally low ocular pulsatile blood flow has been documented in open angle glaucoma, 64,65 low-tension glaucoma, 66 diabetic retinopathy, 46 retinitis pigmentosa, 50 occlusion of the central retinal vein, age-related macular degeneration, 48,67,68 and retinal detachment. 52 In this respect, ocular pulsatile blood flows less than 500 μ l min −1 compared with the mean ocular pulsatile blood flow of 740 μ l min −1 in healthy eyes should be considered abnormal and suspect of ocular disease. Further, in studies of pulsatile blood flow and vision in patients with asymmetric disease the ischemia has been found to be more severe in the eyes with visual loss than in the contralateral eyes without visual loss, including open angle glaucoma (e.g., Fontana et al. 69 ). The onset and progression of the ocular ischemia varies between discrete areas of the retinal and choroidal circulations, 19
Published Version
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