Effects of Latanoprost on Choroidal Blood Flow Regulation in Human Subjects
Status:
Completed
Trial end date:
2010-01-01
Target enrollment:
Participant gender:
Summary
Latanoprost is a synthetic prodrug of 17-phenyl-substituted prostaglandin F2α analog. Used at
a dose of one drop per day, it has been reported to produce a 30 to 35% reduction in
intraocular pressure. Its mechanism of activation involves augmentation of the eye's natural
uveoscleral outflow capacity .
There is evidence that ocular blood flow plays a role in the clinical course of glaucoma.
Glaucoma medication that lowers IOP simultaneously increases ocular blood perfusion pressure,
which in turn may increase ocular blood flow.
This could well contribute to the partially contradicting results concerning ocular
hemodynamic effects of latanoprost. In vitro studies indicate that latanoprost has no effect
on ocular vascular tone in therapeutical doses. By contrast, it has been reported in several
studies that latanoprost 0.005% increases pulsatile ocular blood flow in patients with
primary open angle glaucoma and normal tension glaucoma. This increase in pulsatile ocular
blood flow mainly reflects an increase in the choroidal circulation.
Little is known about the potential effect of latanoprost on choroidal blood flow regulation
in humans. The present study therefore tries to elucidate whether treatment with latanoprost
may alter choroidal blood flow regulation during artificial changes in ocular perfusion
pressure. In addition, the present study aims to clarify whether the change in choroidal
blood flow after latanoprost administration are due to direct vasoactive effects or due to
the increase in ocular perfusion pressure. The second alternative may have important
implications on our understanding of glaucoma treatment, because reduction of IOP may then
per se result in normalization of ocular blood flow regulation.