Diurnal and nocturnal effects of brimonidine monotherapy on intraocular pressure

To investigate the effect of brimonidine monotherapy on intraocular pressure (IOP) during the nocturnal/sleep period.

Prospective, open-label experimental study.

Fifteen patients with newly diagnosed open-angle glaucoma or ocular hypertension (ages, 46-72 years).

Baseline data of 24-hour IOP in untreated patients were collected in a sleep laboratory. Measurements of IOP were taken using a pneumatonometer every 2 hours in the sitting and supine body positions during the 16-hour diurnal/wake period and in the supine position during the 8-hour nocturnal/sleep period. Patients were treated afterward with 0.1% brimonidine 3 times per day for 4 weeks, and 24-hour IOP data were collected under the same laboratory conditions.

Diurnal and nocturnal IOP means under the brimonidine treatment were compared with the baseline.

The diurnal IOP mean was significantly lower under the brimonidine treatment than the baseline IOP in both the sitting and supine positions. There was no statistically significant change in IOP under the brimonidine treatment from the baseline during the nocturnal period.

Although 0.1% brimonidine monotherapy significantly lowered IOP during the diurnal/wake period, it did not significantly lower IOP during the nocturnal/sleep period.

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