Evaluation Of Brimonidine's Effect On Scotopic Mydriasis After Cataract Surgery

This study aimed to evaluate the variation of pupil diameter under photopic and scotopic conditions before and after cataract surgery, as well as to investigate whether topical brimonidine could limit scotopic mydriasis following cataract surgery.

Unidade Local de Saúde Almada Seixal, Almada, Portugal

Dynamic pupillometry was conducted using the MYAH Optical Biometer and Corneal Topographer to measure pupil diameters under both scotopic and photopic conditions. Measurements were taken at two appointments: prior to cataract surgery and one month postoperatively. During the second appointment, pupil diameters were recorded both before and 10 minutes after the administration of one drop of brimonidine (0.25 mg/mL). Statistical significance was set at p < 0.05.

A total of 54 eyes from 54 patients (55.56% females; 44.44% males) were included in the study, with a mean age of 70.85±8.84 years. Mean photopic pupil diameter was 2.73±0.76 mm before cataract surgery and 2.45±0.62 mm one month after cataract surgery (p=0.64). Mean scotopic pupil diameter before surgery was 4,34±1.03 mm. Mean scotopic pupil diameter one month post operatively was 3.97±0.75 mm (p=0.42). After application of brimonidine, mean scotopic pupil diameter was 3.46±0.50 mm. Post operatively, following the application of brimonidine, the mean variation in pupil diameter under scotopic conditions was -0.50±0.22 mm (p < 0.05), indicating a significant decrease in mydriatic response.

Our study demonstrated a reduction in pupil diameter under both photopic and scotopic conditions one month following cataract surgery. Furthermore, the application of brimonidine showed a statistically significant effect in limiting mydriasis under scotopic conditions in the postoperative period. These findings suggest that brimonidine may serve as a valuable clinical option for managing dysphotopsias after cataract surgery.