Reduction Of Corneal Epithelial Thickness During Using Timolol For Myopic Regression Following Smile: A Case Report

We report that the decrease in corneal epithelial thickness occurs during topical medical treatment of 0.5% Timolol eye drops for a case of myopic regression following SMILE, and that there is an association with improvement in visual acuity and refraction.

In previous publications, possible effects of 0.5% Timolol eye drops on myopic regression may be the backward movement of protruded cornea by lowering the Inter ocular pressure.But it's still controversial.The recent availability of corneal epithelial imaging by Fourier domain optical coherence tomography(FD-OCT) provides a practical tool for in vivo epithelial mapping.Central epithelial thickening may play a crucial role in the development of myopic regression following SMILE.

A 27-year-old female patient suffered from blur vision of both eyes for 1 month after undergoing 1-year of SMILE procedure. Her preoperative SE(diopters) of both eyes were -6.75D. Epithelial thickness map showed that the central epithelial thicknesss(CET) thickened significantly compared to that before SMILE. Manifest refraction was -1.0D in both eyes. The eye axis was the same as that before SMILE. 0.5%  Timolol eye drops twice a day was prescribed. After 2 weeks, she claimed that her VA had improved while CET was decreased a little bit compared to the initial of medical treatment.  After 1 month of medical treatment of one eye drops only, her UNVA  was back to normal(20/20) while CET decreased back to normal(the same as before  SMILE). And this patient showed a stable refraction and CET for 3 months after termination of eye drops.

The possilble effects of 0.5% Timolol eye drops on myopic regression may be the reduction of corneal epithelial thickness. We expect that this case report adds to the existing literature on this subject.