No abstract

No abstract

No abstract

(BrJ Ophthalmol 1996;80:1055-1059 The aetiology of the glaucomas remains obscure. Currently two hypotheses are most credible: a mechanical theory, which proposes that excessive pressure deformation of the optic nerve head triggers cell death,2 and a vascular theory, which argues that vascular insufficiency (or vasospasm) tion between flow velocities in two major retrobulbar vessels (the ophthalmic and central retinal arteries) and the IOP, we used scleral suction to vary IOP over a wide range in healthy eyes. We could then determine if blood velocities in these two vessels were dependent on ocular tension. Materials and methods SUBJECTSAll subjects had normal eye examinations, and no history of systemic or ocular hypertension. Measurements were made on the left eye; 11 volunteers were involved in studies of the ophthalmic artery, and nine other volunteers were included in investigations of the central retinal artery. Procedures were reviewed and approved by human subject protection committees at Indiana University and the University of Miami, and subjects signed informed consent before participating. All experimental procedures conformed to the tenets of the Declaration of Helsinki.