Mechanisms leading to an acute rise in intraocular pressure in retinal vein occlusion.

Forty patients with retinal vein occlusion were studied to investigate possible mechanisms leading to an acute rise in intraocular pressure. A rise in intraocular pressure on recumbency was found in 64% of eyes with a central retinal vein occlusion and 65% of eyes with a branch retinal vein occlusion. This finding correlated with glucose tolerance test score, and may be the result of abnormal glucose tolerance in these patients. Following provocative testing using pilocarpine and phenylephrine, no eye showed irido-corneal contact or angle closure, however over 50% of eyes release pigment into the anterior chamber. Fifty-two per cent of central retinal vein occlusion and 71% of branch retinal vein occlusion eyes that released pigment showed a rise in intraocular pressure.