The Effect of Photochromic Contact Lenses on Pupil Size.

Objectives: Photochromic contact lenses (PCL) are designed to increase the comfort of patients, in bright light conditions. The aim of the study was to evaluate the effect of PCL on pupil size.

Methods: The study was conducted with 30 patients who were admitted to the contact lens department. Automated pupilography images of the right eyes of patients were obtained without contact lenses (group 1) in scotopic (S: 0.4 lux), mesopic (M: 4.0 lux), and photopic (p=40 lux) conditions. The procedures were repeated with silicone hydrogel contact lenses (Group 2) and with silicon hydrogel PCL (group 3).

Results: Mean age was 23.87±3.27 (17-30) years and male/female ratio was 10/20. The mean spheric equivalent of their right eyes was -3.60±1.73 (-0.50--7.50). Pupil diameters of Group 3, under scotopic conditions, were larger than Group 1 and 2 (p=0.001, p=0.044). There was no difference between groups under mesotopic and photopic conditions. Pupil diameters at the different illumination levels were similar regarding gender.

Conclusion: Similarity in mesotopic and photopic pupil sizes compared to all groups may be a result of insignificant pupil changes of photochromic lenses in indoor conditions or insufficient time for lens activation.