PurposeTo evaluate and compare the possible changes in pupil size subsequent to panretinal laser photocoagulation (PRP) via conventional laser and pattern scan laser (PASCAL).Patients and methodsForty eyes of 40 patients with diabetic retinopathy were included. 20 eyes had a PRP via conventional laser and formed Group 1. 20 eyes had a PRP via PASCAL laser and formed Group 2. The participants underwent standard ophthalmologic examination at baseline. Automated infrared pupillometry were performed at baseline and month 1.ResultsThe mean pupillary measurements (mm) for Group 1 (in the order photopic, mesopic, and scotopic conditions) were 2.88±0.34, 3.38±0.40, and 3.95±0.38, and changed to 3.64±0.42, 4.18±0.42, and 4.58±0.48, respectively. There was significant increase in pupil size at month 1 (P<0.001, P<0.001, and P<0.00, respectively). For Group 2, they were 2.90±0.38, 3.43±0.36, and 3.90±0.40, and changed to 3.18±0.42, 3.74±0.36, and 4.10±0.38, respectively. There was significant increase in pupil size at month 1 (P=0.018, P=0.014, and P=0.014, respectively). The pupil size increased significantly in both groups in all illumination conditions.ConclusıonWe have demonstrated via automated infrared pupillary measurements that PRP may significantly increase pupil size whether it is performed with conventional laser or PASCAL laser.