Comparing brimonidine 0.2% to apraclonidine 1.0% in the prevention of intraocular pressure elevation and their pupillary effects following laser peripheral iridotomy

To compare the effects of brimonidine 0.2% and apraclonidine 1% on intraocular pressure (IOP) and pupil size in patients undergoing laser peripheral iridotomy (LPI). Forty patients (40 eyes) with occludable angle or angle-closure glaucoma requiring LPI were recruited. Patients were randomized to receive either brimonidine 0.2% or apraclonidine 1% before and after LPI. The IOPs were measured at 1, 2 and 3 h after LPI, and pupil size was measured before and at 45 min after eyedrop instillation. Both parameters were analyzed using the t test. There were 20 patients in each group. The baseline IOP was 17.1 +/- 3.2 mmHg for the brimonidine group and 16.7 +/- 2.8 mmHg for the apraclonidine group (P = 0.67) (t test). The mean IOP 3 h after laser treatment was 18.2 +/- 7.8 mmHg for the brimonidine group and 15.7 +/- 5.6 mmHg for the apraclonidine group (P = 0.25) (t test). There was no statistically significant difference between the two groups in the mean IOP changes at 1, 2, or 3 h after LPI. The mean change in pupil size after brimonidine was -0.33 +/- 0.37 mm and after apraclonidine was +0.90 +/- 0.87 mm. The difference was significant (P < 0.001). Brimonidine 0.2% was found to have an efficacy comparable to that of apraclonidine 1.0% in preventing post LPI IOP spikes. Apraclonidine 1.0% tends to have a pupil dilating effect while brimonidine 0.2% tends to constrict the pupil.