To report the change of pupil sizes according to age and illuminance in the normal Korean population.

Normal Koreans outpatients who never had a history of ophthalmic disease were examined. The patients consisted of 320 eyes of 160 patients, which were classified into 8 age decades (teenage to 80's) with 40 eyes in each age group. The vertical and horizontal pupil size and area under 4 different illuminances (3,500, 1,200, 500, 5 lux) were measured using the Colvard pupillometer® (OASIS Medical, Glendora, CA, USA).

The pupil size was significantly decreased as the age increased under each illuminance. The pupil area measured after dark adaptation was 47.30 mm² in the teenage group, 43.32 mm² in the 20's group, 41.94 mm² in the 30's group, 40.98 mm² in the 40's group, 40.61 mm² in the 50's group, 38.60 mm² in the 60's group, 37.78 mm² in the 70's group and 35.45 mm² in the 80's group. The decrease in pupil area was statistically significant.

In the normal Korean population, a significant decrease in pupil size and area was observed with aging. The present study results provide good basic data for cataract and presbyopia refractive surgery.