Ocular hypotony following retinal vein occlusion
S. S. Hayreh, W. March and C. D. Phelps
In a study of 130 cases of unilateral retinal vein occlusion uncomplicated
by rubeosis, we found that more than 80% of the patients had a lower
intraocular pressure (IOP) in the eye with the occlusion than in the fellow
normal eye. The reduction of IOP was greater with central than with branch
vein occlusion, greater with hemorrhagic than with venous stasis
retinopathy, and greater in patients who had high pressures in their fellow
eyes. The pressure reductions persisted during follow-up periods of up to
two years. How retinal vein occlusion lowers IOP is obscure and may involve
more than one mechanism. Outflow facility was increased (compared to the
fellow eye) in hemorrhagic retinopathy and in branch vein occlusion, both
of which are association with retinal ischemia, but not in venous stasis
retinopathy. Calculated rates of aqueous formation were low in central vein
occlusion but not in branch vein occlusion.
