Single-use Lens Compromise During Selective Laser Trabeculoplasty

Abstract

Precis: Damage to disposable selective laser trabeculoplasty (SLT) lenses correlated with the amount of total laser energy. Furthermore, greater lens damage was associated with diminished patient treatment response. Purpose: Disposable selective laser trabeculoplasty (SLT) lenses have been observed to be damaged during use by the laser, potentially affecting therapeutic response. This study sought to identify factors associated with the magnitude of lens damage and its effect on treatment outcomes. Patient and Methods: We analyzed 113 eyes from 82 patients who underwent SLT between 2020-2021 at an American academic medical center. For each procedure, we recorded baseline patient characteristics, procedure settings, physician age (as a possible factor causing laser defocus due to accommodation), and area of lens damage. Treatment response was calculated as the difference between pre- and post-operative intraocular pressure (IOP). Results: Area of lens damage was associated with greater total laser energy (r=0.34, P<0.001) and greater mean energy per application (r=0.37, P<0.001). IOP reduction decreased with increasing lens damage (r=−0.19, P=0.022). Lens damage was not associated with patient characteristics indicative of glaucoma severity or user settings (physician age, slit lamp used). Greater IOP reduction was associated with higher pre-op IOP (r=0.46, P<0.001) and a smaller cup-to-disc ratio (r=0.22, P=0.036). IOP reduction was not associated with glaucoma severity, patient age, or the number of glaucoma medications. Conclusions: Increased laser damage to disposable SLT lenses was associated with diminished treatment effect. The amount of damage was correlated with total and average laser energy, but not patient or physician factors. Overall, these findings call for reconsideration of using disposable SLT lenses as part of routine practice.