Retinal Ganglion Cell Functional recovery after topical Intraocular Pressure Lowering Therapy in Preperimetric Glaucoma and Its Long-term Benefits Assessed by Pattern Electroretinogram.

Abstract

Purpose : Recent literature has shown that retinal ganglion cell (RGC) dysfunction is reversible in early glaucoma after 3 months of topical intraocular pressure (IOP) lowering treatment, but no studies reported those effects beyond that period in pre-perimetric glaucoma (PPG). The purpose of this cross-sectional study was to evaluate the utility of Pattern Electroretinogram (PERG) for quantifying RGC functional improvement in PPG after IOP lowering treatment over a period of over a year.

Methods : Six subjects (8 eyes) underwent topical IOP lowering treatment based on their clinical examination were observed at Manhattan Ear, Eye, and Throat Hospital over an average of 16.1 months. During this time, participants underwent full ophthalmological exam and were evaluated with Diopsys NOVA PERG [Magnitude (Mag), MagnitudeD (MagD), and MagnitudeD/Magnitude ratio (MagD/Mag ratio)] at three different timepoints: pre-treatment, 4 months (4.2 ± 0.82 months) and 16 months (16.1 ± 3.0) after treatment was started. Goldman applanation tonometry was used to measure IOP at each visit. One-way repeated measures ANOVA were conducted to determine statistical significance.

Results : One-way repeated measures ANOVA was conducted to determine whether there were statistically significant differences in PERG parameters at 4 months and 16 months. Both timepoints demonstrated significantly improved MagD and MagD/Mag ratios (F (1, 7) = 6.351, p= 0.04, partial η² =0.476) and (F (1, 7) = 7.843, p= 0.027, partial η² =0.528). Additionally, MagD and MagD/Mag ratio showed significant increases from pretreatment at both 4 months (47.32% ± 52.91% and 22.46% ± 46.53%) and 16 months (20.02% ± 20.72% and 8.43% ± 21.25%). As expected, the IOP lowering treatments resulted in significant decreases in IOP at both 4 months (-18.10% ± 12.08%) and 16 months (-16.43% ± 8.98%).

Conclusions : PERG is an effective method of measuring RGC functional recovery following administration of topical IOP lowering treatments. Reduction in IOP at both the 4-month and 16-month timepoint correlated with an improvement in MagD and MagD/Mag ratio, with a more pronounced effect during early stages of treatment.

This is a 2021 ARVO Annual Meeting abstract.