Photopic negative response in uveitis patients using Diopsys® ffERG

Abstract

Purpose : Full-field electroretinography photopic negative response (ffERG/PhNR) is used to assess the optic nerve (ON) and ganglion cell layer (GCL) function. Diopsys® (Diopsys Inc, Middletown, PA) is a novel system that can evaluate retinal and nerve electrophysiologic function expediently. This index case-control study compares the parameters of PhNR in uveitis patients with and without suspicious disc, ocular hypertension, or glaucoma.

Methods : Medical records from a tertiary center were reviewed and a total of sixty-eight eyes of thirty-four uveitis patients were enrolled in the study. Twenty-six eyes with intraocular pressure (IOP) ≥ 23, cup disc ratio (CDR) ≥0.7, known diagnosis of uveitic glaucoma, or history of glaucoma medication usage/surgery were compared with 42 eyes having normal IOP, CDR < 0.7. Patients with other forms of optic neuropathy such as , ischemic and diabetic were excluded. The cases and controls were age matched. PhNR and its related parameters, including latency, amplitude (Amp), ratio and MVAindex were measured using Diopsys®NOVA™. The ratio is calculated as: (B-Wave Amp – PhNR Amp) / (B-Wave Amp –A-Wave Amp) and MVAindex is an AI-assisted index designed by the device company to predict the abnormality of PhNR. Detailed clinical examination such as best-corrected visual acuity (BCVA), IOP, and CDR were conducted. Statistical analysis was performed using Stata statistical software (StataCorp LLC, College Station, TX, version 15.1) and the Mann Whitney U test was used to study associations with disease status.

Results : Compared to controls, the latency was significantly increased in cases (p=0.0117); the other 3 parameters including amplitude, ratio, and MVIindex were all significantly decreased (p=0.0016, p=0.0010 and p=0.0143 respectively). A standard regression model revealed that the ratio was the most reliable predictor of disease status (p=0.017). PhNR parameters were poorly correlated with IOP and only the amplitude and ratio had moderate correlations with CDR (0.2942, -0.3107).

Conclusions : Diopsys® ffERG/PhNR device can be useful in objectively detecting ON and GCL dysfunction in a non-invasive rapid setting. Multiple parameters of ffERG/PhNR show significant associations with disease status. This index study revealed that the ratio parameter of the device is the most reliable in detecting disease status.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.