Pilocarpine drops do not reduce intraocular pressure sufficiently in pseudoexfoliation glaucoma

The reason for the poorer prognosis of pseudoexfoliation syndrome glaucomas (PXSG) compared with primary open angle glaucomas (POAG) is not fully understood. An open, comparative, cross-over study was performed in 15 patients (= eyes) with POAG and 15 patients (= eyes) with PXSG. Two different pharmacokinetic principles of drug administration were applied to uncover possible differences in short-term (hours) response to topical antiglaucomatous treatment. Intermittent pilocarpine drop medication (2%) and continuous low-dose pilocarpine delivery by a membrane-controlled Ocusert unit (P40) were used. The 'carry-over' pressure reduction of an ordinary four times a day drop medication was significantly less effective in controlling the morning intraocular pressure (9 a.m.) in PXSG than in POAG. The duration of action of pilocarpine drops was reduced in PXSG. Defining 'normotensive' pressure as < or = 20 mmHg, only 1 of the 15 PXSG eyes (6.7%) reached a normotensive level in the morning, compared with 8 of the 15 POAG eyes (53.3%). Using a continuous supply of pilocarpine (Ocusert), no differences between POAG and PXSG eyes were found. The study demonstrates the insufficient control of intraocular pressure in PXSG, compared with POAG, by identical antiglaucomatous drop medications. This may suggest an insufficient depot function of topical drugs in PXSG. In consequence, pseudoexfoliation material (PXM) must be sought in eyes with glaucoma, as PXM eyes will probably benefit from a more intense medical treatment compared with eyes without PXM.