Background: Brimonidine is an α-adrenergic receptor agonist that has the potential to elevate the upper eyelid through stimulation of Muller’s muscle. We examined palpebral fissure height changes before and after administration of brimonidine 0.025% in healthy patients to determine if there was a significant effect on palpebral fissure size.

Subjects/Methods: Forty-three healthy subjects (86 eyes) participated in this study double-blind, randomized, placebo-controlled study. Eyes were randomized to receive brimonidine 0.025% or a placebo saline drop. Standardized photographs were taken before administration of the products, as well as 5 minutes, 15 minutes, and 30 minutes later. Ocular redness, itch, pain, and burning were evaluated at each time point. Intraocular pressure (IOP) was evaluated prior to product administration and after 30 minutes. Palpebral fissure height (PFH) was measured from the photographs using Adobe Photoshop.

Results: The mean PFH at baseline prior to brimonidine 0.025% was 9.64 ± 1.71mm in the treatment group. The mean PFH at 5-, 15-, and 30-minutes following drug instillation was 9.92 ± 1.33mm (p=0.71, CI 95% (-0.21, 0.19)), 9.85 ± 1.42mm (p=0.29, CI 95% (-0.32, 0.10)), and 9.86 ± 1.32mm (p=0.80, CI 95% (-0.13,0.16)) respectively. No statistically significant differences in PFH or IOP were found between the brimonidine 0.025% and saline-treated groups. Ocular redness was significantly lower in brimonidine 0.025% treated eyes compared to saline-treated eyes at all time intervals (p=0.001).

Conclusions: Brimonidine 0.025% does not significantly change palpebral fissure height in healthy patients. It significantly reduced ocular redness and was well tolerated by subjects.