The effects of systemic medications on ocular blood flow

Abstract

This article reviews the effects of systemic medications and some native vasoactive molecules on ocular blood flow (OBF). Some evidence exists for a positive effect of centrally acting calcium-channel blockers, nitric oxide precursors, adenosine, histamine, estrogens, and ginkgo biloba extract, while evidence for a negative effect on OBF exists for endothelin-1 and indomethacin. Some other molecules appear to have mixed effects, depending on the ocular vascular bed studied or the study protocol. In addition, medically induced changes in systemic blood pressure (BP) have an important impact on OBF, and the direction and magnitude of this effect may depend on the disease status of the patient and of the eye, as well as the absolute level of BP achieved. There are relatively few studies of the effects of systemic medications on OBF in glaucoma patients, and little is known of the long-term impact of such therapies on the preservation of optic nerve structure and function.

Retinal Blood Flow in Glaucomatous Eyes with Single-Hemifield Damage

“…Few studies have examined the impact of systemic medications and supplements on retinal blood flow in glaucoma patients with controversial results. 47 Topical glaucoma medications reduce the IOP and may indirectly increase the MOPP. An increase in MOPP does not necessarily lead to an increase in RBF because the retinal circulation has autoregulatory mechanisms, unless the perfusion pressure falls below the lower limit of autoregulation, or the neurovascular coupling fails.…”

Female Reproductive Factors and Major Eye Diseases in Asian Women –The Singapore Malay Eye Study

“…33,34 These receptors, when activated, have been shown to enhance the activity of endothelial-based type-3 nitric oxide synthase with resultant local release of nitric oxide causing vasodilation. [35][36][37][38] In view of the role of ocular ischemia and increased vascular resistance in the development of glaucoma, 38,39 a reciprocal lack of estrogen in post-menopausal women, and hence a reduction in estrogen receptor activation, may result in reduced levels of nitric oxide and subsequent vascular resistance and ischemia. Estrogen receptors localized in human neuroblastoma cells have shown a potent protection against apoptotic stimuli.…”

Feasibility of creating a normative database of colour Doppler imaging parameters in glaucomatous eyes and controls

“…Certain centrally acting calcium-channel blockers, angiotensin inhibitors and alpha-adrenergic agonists have been shown to alter ocular blood flow in various ways 92 93. Thus, it is unremarkable that whether studies allowed antihypertensive medications significantly altered mean CDI values.…”