Pupil Diameter, Corneal Thickness, and Anterior Chamber Alterations Following Topical Olopatadine Hydrochloride 0.1%: A Single-Masked Randomized Controlled Clinical Study.

Olopatadine hydrochloride 0.1% is one of the known primary topical treatments in ocular allergy. Although olopatadine is a worldwide used medication, the changes in pupil diameter, cornea, and anterior chamber associated with its use have not been studied in detail. In this prospective study, we aimed to determine the amount of mydriasis and explore the possible corneal and anterior chamber alterations after 0.1% topical olopatadine. A total of 77 eyes from 77 ocular-allergy diagnosed patients between 18 and 40 years were investigated in this prospective study. Thirty-nine eyes of 39 patients received topical olopatadine, and 38 eyes of 38 patients received sterile distilled water, randomly. Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) topography was used to assess the pupil and anterior chamber measurements at baseline and after 45 min of olopatadine or sterile distilled water instillation. The differences between the baseline and 45th-min measurements for corneal thickness, anterior chamber depth, angle, and volume did not reach a statistical significance in the olopatadine or control groups. The pupil diameter significantly increased from 3.19 ± 0.62 to 3.36 ± 0.62 mm in the olopatadine group ( < 0.001), and remained relatively unchanged in the control group ( = 0.06). Olopatadine 0.1% does not lead to a significant change in corneal topography or anterior chamber parameters. However, it causes a slight but statistically significant increase in pupil diameter.