Short-term Effect of Topical Brimonidine Tartrate on Intrastromal Corneal Pressure in Rabbits

PURPOSE: Because topical brimonidine tartrate has been reported to decrease flap adherence in the early postoperative period after LASIK, its effect on the intrastromal corneal pressure (ICP) was evaluated. METHODS: An interventional, prospective, animal study was performed. Intrastromal corneal pressure Was recorded for 45 minutes in eight eyes of rabbits treated with topical brimonidine tartrate three times daily for 3 consecutive days (study group); eight contralateral eyes were treated with artificial tears (control group). All measurements were performed by the same, masked investigator. RESULTS: Mean ICP was -4.00+/-2.90 mmHg, -6.70+/-3.00 mmHg, and -9.00+/-4.50 mmHg at 15, 30, and 45 minutes, respectively, in the control group. In the study group (brimonidine-treated eyes), the ICP readings were +2.75+/-2.90 mmHg, -2.50+/-3.00 mmHg, and -8.50+/-5.00 mmHg at the same time points, respectively. The differences in the ICP between both groups were statistically significant at 15 minutes (P=.01), but no significant difference was found at 30 or 45 minutes (P=.20 and P=.80, respectively). CONCLUSIONS: Topical treatment with brimonidine tartrate induces a significant decrease in ICP at 15 minutes. This effect on ICP may explain the decreased corneal flap adherence reported in eyes treated with this drug. [J Refract Surg. 2010;26(7):533-535.] doi :10.3928/1081597X-20100310-01