Effects of adenosine on intraocular pressure, optic nerve head blood flow, and choroidal blood flow in healthy humans.

Purpose: There is evidence from a variety of animal studies that the adenosine system plays a role in the control of intraocular pressure (IOP) and ocular blood flow. However, human data on the effect of adenosine on IOP and choroidal and optic nerve blood flow are not available.

Methods: The effect of stepwise increases in doses of adenosine (10, 20, and 40 micro g/kg per minute, 30 minutes per infusion step) on optic nerve head blood flow, choroidal blood flow, and IOP was determined in a placebo-controlled double-masked clinical trial in 12 healthy male volunteers.

Measurements in the peripheral retina using LDF and laser interferometry are mainly influenced by the choroidal circulation.

Purpose: Two laser based methods for the assessment of ocular hemodynamics in humans have been investigated: laser Doppler flowmetry (LDF) and laser interferometric measurement of fundus pulsation amplitude (FPA). When the laser with either of the two methods is focused onto the fovea it is obvious that only choroidal blood flow contributes to the signals. When the laser is, however, directed to other parts of the retina the situation is more complex.

Partial antagonism of endothelin 1-induced vasoconstriction in the human choroid by topical unoprostone isopropyl.

Background: There is increasing evidence that reduced ocular blood flow plays a role in the pathogenesis of glaucoma. In patients with normal-tension glaucoma, ocular blood flow abnormalities may be associated with dysfunction of the endothelin 1 (ET-1) regulation system.

Objective: To test the hypothesis that unoprostone, a topical docosanoid, may affect ET-1--induced vasoconstriction in the human choroid.