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Study: Brimonidine tartrate shows short-term efficacy for reducing halo, pupil size after LASIK
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Brimonidine tartrate can successfully reduce halo size and pupil size in patients with night-vision symptoms after LASIK, a small 24-hour study by researchers in South Korea found.
Ji Hoon Lee, MD, and colleagues evaluated the effect of Alphagan (brimonidine tartrate 0.2%, Allergan) on halo and pupil size after administering the drug to 28 eyes of 14 patients at Nune Eye Hospital, Seoul, who had symptomatic night-vision difficulties after LASIK. The investigators evaluated pupil size and halo size under scotopic and normal room light conditions. The effect of brimonidine tartrate 0.2% was measured 30 minutes and 1, 6, 12 and 24 hours after instillation.
The investigators found a statistically significant correlation between pupil size and halo size (P < .0001), with pupil size and halo size decreasing significantly 30 minutes after brimonidine tartrate 0.2% instillation under both luminance conditions (P < .0001).
Under normal room light, pupil and halo size remained decreased until the last measurement at 24 hours, they noted.
Under scotopic conditions, pupil size returned to its baseline value at 24 hours while halo size remained decreased.
"The maximum effect on halos was observed after 6 hours, when the mean reduction over preinstillation size was 28.2% and 29.1% under normal room light conditions and scotopic conditions, respectively," the authors said.
The study is published in the June issue of Journal of Cataract & Refractive Surgery.