Corneal endothelial cell loss associated with selective laser trabeculoplasty

Abstract

Purpose : Selective laser trabeculoplasty (SLT) is a procedure increasingly used as first-line therapy to reduce intraocular pressure (IOP) in patients with ocular hypertension (OHT) or glaucoma. This subgroup analysis evaluated corneal endothelial cell loss (CECL) associated with SLT treatment in a randomized, phase 3 study.

Methods : A 52-week, randomized, phase 3, paired-eye comparison study (NCT02636946) evaluated bimatoprost implant compared with SLT in patients with open-angle glaucoma or OHT whose IOP was inadequately managed with topical medication for reasons other than medication efficacy. SLT was performed on Day 1 using single-burst mode and a standard fixed 400 µm spot size with ~100 contiguous, non-overlapping spots delivered 360° in the angle; power began at ~0.6 mJ and was titrated between ~0.4 and ~1.2 mJ as needed. Patients were randomized to treatment with implant or SLT in the worse eye; contralateral eyes received the alternate treatment. Corneal endothelial cell density (CECD) was assessed as a safety parameter at multiple time points throughout the study with a Konan CellChek noncontact specular microscope present at each site. The imaging technician was qualified by an experienced reading center (Cornea Image Analysis Reading Center [CIARC], Case Western Reserve University) commonly used for registration studies. CECD was quantified by the reading center. All available data from the primary database lock, when the last enrolled patient completed the Week 24 visit, were analyzed.

Results : Mean (SD) CECD in SLT-treated eyes (n=141) was 2487 (311) cells/mm² at baseline and decreased during the study; at Week 24 the mean (SD) CECD was 2422 (329) cells/mm². Among all SLT-treated eyes, 9.9% (14/141) had ≥10% corneal endothelial cell loss (CECL), 5.7% (8/141) had ≥15% CECL, and 3.5% (5/141) had ≥20% CECL during a mean (SD) follow-up of 317 (83) days.

Conclusions : Previous open-label studies with 1 month follow-up have generally reported transient corneal changes and reduction in CECD after SLT with limited follow up. Results of this phase 3 study suggest that persistent CECL may be a previously unrecognized side effect of SLT that becomes evident with longer follow-up.

This is a 2021 ARVO Annual Meeting abstract.

 

Figure. A) Distribution and kernel density of CECD changes from baseline at Week 52. B) CECD in the 5 eyes with ≥20% CECL after SLT; 3 of the 5 patients had reached Week 52 at the time of the database lock. *≥20% CECL from baseline (BL).