Reduction of IOP
remains the sine qua non of glaucoma treatments, yet retinal ganglion
cell apoptosis may be induced by ocular ischemia, via a cascade of events
initiated by vascular dysfunction in the eye. Optimal efficacy in glaucoma
treatment, therefore, includes IOP
reduction combined with the metabolic advantages of increased ocular perfusion.
A vasoprotective
agent provides a metabolic advantage for tissue survival in glaucoma. Combining IOP reduction with a
vasoprotective agent is a new approach in the treatment of glaucoma. Consideration of a compound therefore
requires both analysis of its effect on IOP, and a comprehensive analysis of
its effect on all ocular vascular beds relevant to glaucoma.
We have performed
such a comprehensive analysis on Latanoprost, Dorzolamide, Timolol, and
Cosopt. Dorzolamide is an
effective ocular hypotensive agent that accelerates blood velocity in the
retinal and superficial optic nerve head without no apparent effect on
retrobulbar hemodynamics. While
Latanoprost had no significant effect on ocular hemodynamics, it induces an
increase in resistance to flow in the ophthalmic artery when compared to the
effect of Dorzolamide. Cosopt
significantly improved retinal circulation compared to Timolol treatment.