The influence of tropicamide on intraocular pressure.

Elevation of intraocular pressure by many cycloplegic drugs has been reported to occur in eyes in which the filtration angle remained open during mydriasis. Tropicamide 1% is also capable of this phenomenon in patients with open angle glaucoma who are being medicated with pilocarpine. However, in normal eyes as well as those with untreated open angle glaucoma, this cycloplegic has a relatively small effect on intraocular pressure. It is postulated that this difference between the subject groups may be due to competitive inhibition of the miotic at the receptor site in those treated with pilocarpine. In 3 patients in whom the intraocular tension elevation was found to be quite marked, heavy pigments showers in the anterior chamber occurred which suggested an outflow obstructive phenomenon similar to that seen in "Pigmentary Glaucoma."