Evaluating the Effect of Pulse Energy on Femtosecond Laser Trabeculotomy (FLT) Drainage Channels in Human Cadaver Eyes

Abstract

Purpose : Femtosecond laser trabeculotomy creates aqueous humor drainage channels through the trabecular meshwork and is an emerging non-invasive treatment for open angle glaucoma. The purpose of this study is to investigate the effect of pulse energy on drainage channel creation during FLT.

Methods : An FLT laser (ViaLase Inc., Aliso Viejo, CA) was used to create drainage channels through the trabecular meshwork (500 μm wide by 200 μm) in human cadaver eyes using pulse energies of 10, 15, and 20 μJ. Following treatment, tissues were fixed in 4% PFA for OCT evaluation. H&E stain imaging was also performed to confirm the creations of the drainage channels through the TM. Channels were full thickness, partial thickness, or not observable.

Results : 15 μJ and 20 μJ pulse energies had a 100% success rate in creating full FLT channels as imaged by OCT. 10 μJ pulse energy resulted in no channels (n=3), a partial channel (n=1), and a full FLT channels (n=2). Sample channels are shown in Figure 1. H&E microscopy further verified that the TM was fully penetrated with created channels by the femtosecond laser with no collateral damage in adjacent tissue.

Conclusions : 15 µJ is an adequate pulse energy to reliably create aqueous humor drainage channels during FLT in human cadaver eyes. OCT is valuable tool when evaluating FLT.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.