The reason for the poorer prognosis of pseudoexfoliation syndrome glau
comas (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 anti-glaucomatous treatment. Intermittent pilocarpine drop
medication (2%) and continuous low-dose pilocarpine delivery by a mem
brane-controlled Ocusert unit (P40) were used. The 'carry-over' pressu
re reduction of an ordinary four times a day drop medication was signi
ficantly less effective in controlling the morning intraocular pressur
e (9 a.m.) in PXSG than in POAG. The duration of action of pilocarpine
drops was reduced in PXSG. Defining 'normotensive' pressure as less-t
han-or-equal-to 20 mmHg, only 1 of the 15 PXSG eyes (6.7%) reached a n
ormotensive level in the morning, compared with 8 of the 15 POAG eyes
(53.3%). Using a continuous supply of pilocarpine (Ocusert), no differ
ences between POAG and PXSG eyes were found. The study demonstrates th
e 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 consequen
ce, pseudoexfoliation material (PXM) must be sought in eyes with glauc
oma, as PXM eyes will probably benefit from a more intense medical tre
atment compared with eyes without PXM.