Effect of pupil size on dynamic visual acuity

This study was conducted to assess the effect Of pupil size on dynamic visual acuity (DVA). 60 young healthy men (M=28.1 yr., SD = 3.9) with normal vision were divided into three age-matched groups by pupil size: dilated (n-20), Unchanged (n=20), and constricted (n=20). DVA was measured binocularly with free-head viewing before and at 30 min. after each drop was instilled, Each of the three groups got a different amount. The sizes of the constricted, unchanged, and dilated pupils were 2,8 min (SD = 05), 4.1 min (SD = 0.3), and 7.8 mm (SD = 0.5), respectively. The pupil size x DVA interaction was significant (F-2.114 = 6.07). DVA in the constricted pupil decreased, but that in the dilated Pupil increased (paired t test). DVA in the unchanged pupil did not change significantly (paired t test), pupil size is possibly one of the factors which may affect DVA measurement.