The Influence of Phenylephrine, Mydrin-P(R) and Cyclopentolate on Intraocular Pressure Elevation

ABSTRACT

Pharmacological mydriasis can cause an acute elevation of intraocular pressure without obstruction of angle. A prospective study of 80 normal Korean subjects(149 eyes) and 20 Korean primary open angle glaucoma patients(49 eyes) was performed in order to obtain and compare effects on intraocular pressure, pupil size and aqueous floater by phenylephrine, Mydrin-P(R) and cyclopentolate and to investigate wheather intraocular pressure elevation occurs also in Korean eyes after pupil dilation. Significant pressure elevation(6mmHg or more) was rare in normal subjects while incidence of 25% with Mydrin-P(R) and 50% with cyclopentolate occurred in primary open angle glaucoma patients. Thus, stronger cyclopegics induced intraocular pressure elevation more frequently. Statistically significant correlation between intraocular pressure elevation and aqueous floater did not exist in primary open angle glaucoma patients but only existed with cyclopentolate in normal subjects. Maximum mydriasis by phenylephrine, Mydrin-P(R) and cyclopentolate occurred in 60, 90 and 90 minutes respectively. There is a potential hazard of routine dilation of eyes with cycloplegic agents in primary open angle glaucoma patients in both Korean and occidental eyes.