The Effects of Age on Pupil Diameter at Different Light Amplitudes

INTRODUCTION: This study was an evaluation of pupil response at different light amplitudes in healthy individuals in different age groups.
METHODS: A total of 210 eyes of 105 healthy individuals were included in the study. The participants were divided into 4 groups at 15-year age intervals: 15-30, 31-45, 46-60, and over 60 years. The dimensions of the pupil were measured with a pupillometer at 5 different light amplitudes: 0, 1, 10, 100, and 200 cd/m2. The average pupil diameter in the groups was compared and changes in pupil diameter were correlated for each light amplitude according to age.
RESULTS: The mean pupil diameter was 4.96+0.82 mm in males, and 4.95+0.87 mm in females at 0 cd/m2 light amplitude, and 2.44+0.19 mm and 2.40+0.19 mm, respectively, at 200 cd/m2 light amplitude. The differences were not statistically significant (p>0.05). In addition, there was no significant difference in pupil size between the right and left eye at any light amplitude (p>0.05). Pupil diameters were found to be smaller at all light amplitudes with advanced age. There was a negative significant correlation between pupil size and age at all light amplitudes (p<0.05). The correlation was stronger at low light amplitudes.
DISCUSSION AND CONCLUSION: Pupil response to light is influenced by age. This should be taken into consideration when evaluating pupil reaction.