The effect of acetazolamide on the retinal circulation

Abstract

The effect of the carbonic anhydrase inhibitor, acetazolamide, on the retinal circulation was studied in 10 healthy volunteers. Acetazolamide was administered intravenously at a dose of 500 mg. Retinal blood flow was determined from red cell velocity using laser Doppler velocimetry and vessel diameter measurement using computerised digital image analysis of monochromatic fundus photographs. There was a significant increase in retinal blood flow at 30 minutes and 60 minutes after acetazolamide injection (p = 0.002). Retinal vessels showed vasodilatation reaching significant levels 60 minutes after the injection (p < 0.03). An increase in red cell velocity was observed at 30 and 60 minutes (p < 0.002). A significant reduction in intraocular pressure occurred at 30 and 60 minutes after the injection (p < 0.001). The mechanisms responsible for the increase in retinal blood flow acted via significant increases in perfusion pressure (p < 0.05), red cell velocity (p < 0.002) and retinal vessel dilatation (p < 0.03). An increase in tissue PCO2 and a reduction in pH are thought to be responsible for the vascular dilatation. The increase in retinal blood flow with acetazolamide may serve to limit optic disc and retinal ischaemia in acute glaucoma and central retinal artery occlusion respectively.

Pseudotumor Cerebri in Children With Sickle Cell Disease: A Case Series

“…42 Other studies have demonstrated that increased tissue partial pressure of carbon dioxide and a subsequent reduction in pH can increase retinal perfusion pressure, red cell velocity, and retinal vessel dilatation after the administration of acetazolamide. 43 This process could serve to decrease papilledema and retinal artery occlusion in patients with ophthalmologic complications of various conditions including SCD.…”

Pharmacotherapy of Glaucoma

“…99 While retinal blood flow, in general, seems to increase, blood flow in the peripapillary region of the retina appears to be reduced after treatment with acetazolamide. 99,100 Osmotics. Hyperosmotics such as mannitol or glycerol are potent ocular hypotensive drugs and are used in patients with acute IOP increase.…”

A review of central retinal artery occlusion: clinical presentation and management

“…47 (iii) Intravenous acetazolamide and mannitol, plus anterior chamber paracentesis, followed by withdrawal of a small amount of aqueous fluid from the eye to increase retinal artery perfusion pressure by reducing intraocular pressure. 29,43,47,48 (iv) Multimodal stepwise conservative approaches involving combinations of: ocular massage, globe compression, sublingual isosorbide dinitrate, intravenous acetazolamide, followed by intravenous mannitol, methylprednisolone, streptokinase, retrobulbar tolazoline, and different anticoagulants. 2 Conservative types of treatment for acute CRAO have been used either as monotherapy or as combination therapy.…”