Abstract
Purpose :
Brimonidine 1 to 2% concentration is a well-known glaucoma treatment, and it's lower concentration of 0.025% has been shown to effectively reduce eye redness. However, little is known regarding other ocular and visual effects of brimonidine 0.025%. This study evaluated the effect of brimonidine 0.025% ophthalmic solution on contrast sensitivity (CS), intraocular pressure (IOP), and pupil size in an adult population.
Methods :
This investigation was a randomized, placebo-controlled, within-subjects, double-masked study. Brimonidine 0.025% ophthalmic solution was instilled on one randomly-selected eye of each subject, and a placebo (preservative-free artificial tear) was instilled in the contralateral eye. Subjects were scheduled to have CS, IOP, and pupil size performed before instillation (baseline), at 30 minutes, and 2 hours after instillation.
Results :
Brimonidine-treated eyes performed significantly better on CS (averages across both follow up visits at 1.5, 3, 6, 12, and 18 cycles per degree stimuli - Table 1) both under photopic (p<0.01) and scotopic conditions (p=0.04) compared to placebo. IOP change in the brimonidine-treated eyes slightly, but not significantly, increased (0.11 ± 1.72 mmHg; p=0.83) at 30 minutes after instillation and then showed a significant decrease (-1.42 ± 1.35 mmHg; p<0.01) from baseline at 2 hours after instillation. In placebo-controlled eyes, there was a non-significant reduction in IOP (-0.61 ± 1.29mmHg; p=0.23) at 30 minutes after instillation, and then a non-significant increase (0.11 ± 1.76mmHg; p=0.83) at 2 hours after instillation. Scotopic pupil size significantly decreased from baseline at 30 minutes in both the brimonidine and placebo eyes (-1.04 ± 0.62mm; p<0.001 and -0.39 ± 0.36mm; p=0.05, respectively). Significant reductions of scotopic pupil size from baseline were also found at 2 hours in brimonidine eyes and placebo eyes (-1.09 ± 0.82mm; p<0.001 and -0.48 ± 0.48mm; p=0.01, respectively). There was a significant difference in pupil size between brimonidine treated eyes and placebo eyes across both follow up visits after adjusting for the baseline (p<0.001, effect size=1.73).
Conclusions :
Eyes treated with brimonidine 0.025% had significantly better contrast sensitivity under scotopic and photopic luminance, lower IOP, and smaller scotopic pupil size compared to placebo-treated eyes. Further study is warranted.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.