[Decrease in intraocular pressure following administration of the local carbonic anhydrase inhibitor...

We studied the effect of a single dose of the local carbonic anhydrase inhibitor, MK-927, on lowering IOP in 24 patients with bilateral primary open-angle glaucoma or ocular hypertension and compared it with the effect of pilocarpin in 9 patients. Following a washout of any glaucoma medication of 3 to 14 days, a diurnal IOP curve was performed. Two to seven days later one eye received a single drop of 2% MK-927 while the other eye received placebo and the diurnal IOP curve was repeated. MK-927 treated eyes showed a peak mean IOP change of 10.5 mmHg (33.1%) occurring at 4.5 h postmedication. In nine eyes treated with pilocarpin 1% q.d., the mean reduction of the mean IOP was 7.0 mmHg (22.1%) compared to no treatment. The same eyes showed a mean reduction of mean IOP of 6.1 mmHg (18.9%) following a single dose of MK-927. In contrast, the mean reduction of the maximal IOP treated with pilocarpin was 7.3 mmHg (25.8%) and 10.2 mmHg (34.2%) following MK-927. Considering the IOP lowering of MK-927 shown here, the possibility of a topically effective glaucoma therapy by local carbonic anhydrase inhibitor seems to be established. The IOP lowering effect of MK-927 appears to be similar to that of pilocarpin 1%.