A Comparison of Xenon- and LED-based Full-field Electroretinography in Patients with ABCA4-related Macular Dystrophy

Abstract

Purpose : The long-established use of xenon flashes in full-field electroretinography (ERG) is being superseded by LED-based stimuli typically involving different recording systems, with potential consequences for studies that involve longitudinal or legacy data. This study compares retrospective recordings from xenon- and LED- based ERG systems in patients with confirmed ABCA4-related macular dystrophy (patients with Stargardt disease and normal full-field ERGs), with the aim of examining potential differences in response components.

Methods : Patients who attended Moorfields Eye Hospital with at least one molecularly confirmed mutation of the ABCA4 gene, a clinical presentation consistent with Stargardt Disease, and with macular dystrophy (full-field ERGs that fall within “normal” reference limits) were ascertained. Full-field ERGs incorporated the International Society for Clinical Electrophysiology of Vision (ISCEV) standard and were elicited using either LED- (Group A; “Diagnosys ColorDome™” system) or xenon-flash (Group B; “CH electronics” system) stimuli, each obtained using a different recording system. The dark-adapted strong flash (DA 10.0) ERG, light-adapted single flash cone (LA 3.0) ERG and 30Hz flicker (LA 30Hz) ERG were compared between the two groups.

Results : A total of 344 patients were analysed. There were 122 subjects in Group A (Mean age 37.5 years, SD: 14.0. Mean pupil size: 8.4; SD: 0.8) and 222 subjects in Group B (Mean age 36.8 years, SD: 14.7. Mean pupil size: 8.2; SD: 1.1). Amplitudes for the DA 10.0, LA 3.0 and LA 30Hz flicker ERGs did not show statistically significant differences (Table 1) between the 2 Groups. Peak times for the three tests showed small but statistically significant differences (p<0.001) between Group A and Group B.

Conclusions : The use of xenon- or LED- based flash stimuli and recording methods are important considerations when evaluating ISCEV-standard ERGs in patients with ABCA4-related macular dystrophy. The findings are relevant not only to studies that aim to monitor retinal function longitudinally using different equipment, but also those seeking to establish ERG reference ranges, pool data or interrogate legacy ERG data sets with novel methods, such as artificial intelligence.

This is a 2021 ARVO Annual Meeting abstract.

 

Table 1. Mean values for the main ERG components and Mann Whitney U p-value between Group A and Group B