The Antimydriatic Effect of Brimonidine 0.15% on the Dark-adapted Pupil in Dark Brown Irides

Abstract

Purpose: To analyze the effect of the daily use of brimonidine tartrate 0.15% on the dark-adapted pupil diameter in dark brown irides.

Methods: Twenty-five healthy volunteers administered brimonidine tartrate 0.15% to their right eyes once daily for 3 weeks. Infrared digital photographs of the pupil were taken before administration and 1 hour and 4 hours after administration after dark adaptation (at <0.1 lux ambient illumination for 5 minutes). The diameters of both pupils were measured on the first day, on administration days 7 and 21, and on washout day 7.

Results: Four hours after the first administration, pupils showed a decrease of 0.95±0.74 mm, 1.03±0.94 mm, 0.61±0.85 mm on the first day, administration day 7, and administration day 21, respectively (p<0.01), compared with baseline data. The anti-mydriatic effect of brimonidine was sustained for 3 weeks, but the proportions of the eyes showing a reduction in pupil diameter by 0.5 mm or more were 84%, 76%, 68%, and 52% at 4 hours on the first day, administration days 7 and 21, and washout day 7, respectively.

Conclusions: The anti-mydriatic effect of the daily use of brimonidine 0.15% on dark brown irides in a scotopic condition is maintained during the instillation period but has a tendency to fade over time. This point should be considered when using this compound as a miotic agent.

목적: Brimonidine 0.15% 1일 1회 점안이 갈색홍채에서 암순응반응에 미치는 영향을 알아보고자 한다.

대상과 방법: 갈색홍채의 정상 성인 25명의 우안에 brimonidine 0.15% 안약을 1일 1회 3주간 점안하여 최초값을 기준으로 1주, 3주 후 그리고 중단 1주 후에 각각 점안 전, 점안 1시간, 4시간째 조도 0.1 lux 미만의 암실에서 5분간 암순응한 뒤 적외선 디지털 사진기로 촬영하여 동공크기를 측정하였다.

결과: 점안 후 4시간째 동공크기는 최초값에 비해 점안 시작일, 1주, 3주에 각각 0.95±0.74 mm, 1.03±0.94mm, 0.61±0.85 mm만큼 감소했고(p<0.01), 3주간 항산동효과가 유지됐으나(p<0.05), 점안 후 4시간째 최초값 보다 0.5 mm 이상 감소한 비율은 점안 시작일, 1주, 3주, 중단 1주 후 재점안시 각각 84%, 76%, 68%, 52%로 점차 줄었다.

결론: 갈색홍채에 brimonidine 0.15%를 3주간 점안하는 동안 야간 항산동효과를 보였으나 투약기간의 증가에 따라 효과가 감소하는 경향을 보이므로 축동 목적으로 사용시 이를 고려해야 한다.