Abstract
Purpose: :
Brimonidine has been suggested to relieve postoperative night-vision difficulties related to a large pupil. Echobiometric and ultrasound biomicroscopic changes may occur in Brimonidine application; however, no data available on changes in internal refraction. We aimed to investigate the effects of alpha-2 agonist, brimonidine tartrate 0.2% (Alphagan) on pupil diameter and ocular aberrations.
Methods: :
30 subjects between 20 and 40 years of age, candidate for Laser refractive surgery, were included in the study. OPD Scan (Nidek ARK-10000) was used for the measurements. Baseline and serial measurements were obtained at low mesopic and photopic luminance levels (10 cd/m2 and 100 cd/m2) during 30 minutes interval following instillation of 1 drop of Brimonidine tartrate 0.2% in one eye versus a placebo in the contralateral eye.
Results: :
Both eyes were similar in regard to baseline measurements (p>0.05 for all). At all time intervals. Brimonidine tartrate 0.2% produced a moderate miotic effect ranging 5,65±1,01 mm to 6,48±1,01 mm, which is most significant at 90 minutes after instillation at low mesopic conditions. Also baseline total aberations was significantly decreased at 90 minutes after istillation of brimonidine tartrate (mean;1,51 ±1,48 diopters to 1,35 ± 1,38 diopters; p=0.05). At all time intervals, all Internal aberrations including tilt, high, t.coma, t.trefoil, t.4foil, t.spheric and hiastigma were decreased (p>0,05 for all ). Each was corelated to the decrasing pupil size in moderate (r=0.53) to high degree (r=0.83).
Conclusions: :
Brimonidine decreasing pupil size may alleviate the problems asscociate with night vision in LASIK, and Brimonidine seems to have no significant efffect on internal aberations.
Keywords: pupil • aberrations