Abstract
Purpose::
To evaluate the effect of brimonidine tartrate ophthalmic solution 0.1% (Alphagan P) on pupil diameter and the subsequent change in higher order aberrations (HOA)
Methods::
Eleven eyes of 11 healthy volunteers (average age 28.2 yrs) were included in the study. Three consecutive baseline measurements of pupil diameter and aberrometry were performed with the VISX CustomVue wavefront analyzer (VISX Inc, Santa Clara, California) under scotopic conditions. Subjects were then given one drop of brimonidine tartrate 0.1% and 30 minutes later pupil size and aberrometry were then re-measured. Statistical analysis was done using the 2-tailed Student paired t test.
Results::
Under scotopic conditions, the mean baseline pupil size was 7.6 mm (range 6.0 to 9.1). Thirty minutes after instillation of brimonidine, the mean pupil size was 6.2 mm (range 4.5 to 8.8). All 11 pupils (100%) showed a decrease in size at 30 minutes (p < 0.005). The pupil diameter decreased by 1.0 mm or more in 8 of 11 eyes (73%) at 30 minutes (p < 0.005). The mean decrease in pupil size was 1.35 mm. The mean root-mean-square (RMS) HOA was 0.41 at baseline. The mean RMS HOA 30 minutes after brimonidine instillation was 0.26. The mean decrease in RMS HOA was 0.14. Overall, there was a significant decrease in RMS HOA (p < 0.005) 30 minutes after instillation of brimonidine.
Conclusions::
Brimonidine tartrate 0.1% shows a significant effect in decreasing pupil size under scotopic conditions. This is consistent with previous studies examining brimonidine tartrate 0.15% and 0.2% solutions. As would be expected, with miosis there was a significant decrease in the RMS HOA. Thus, the miotic effect of brimonidine tartrate 0.1% may be beneficial in treating postoperative refractive surgery patients who experience night vision problems associated with a large pupil.
Keywords: pupil • refractive surgery: optical quality • drug toxicity/drug effects