Optic nerve blood flow in glaucoma.

Vascular disorders of the anterior optic nerve, historically, have been described as potential etiologic factors in the development of glaucomatous optic neuropathy. During the past several decades, clinical and experimental evidence of the involvement of vascular aberrations as a potential causative factor or associated risk factor have increased. However, the direct evidence that optic nerve ischemia contributes to glaucomatous optic neuropathy remains limited. Several questions about our current knowledge arise. Can ischemia alone or in combination with other factors cause glaucomatous optic neuropathy? Does our current knowledge of the vascular anatomy and physiology of the optic nerve allow us to understand vascular changes observed in individuals with glaucoma? Can we rely on current measurement techniques to assess and monitor the vascular beds of the optic nerve? This article summarizes the complex nature of the microcirculation in the anterior optic nerve, discusses the possible contribution of vascular factors in the development of glaucoma optic neuropathy, and examines the measurement techniques used in current studies.