Electronegative electroretinogram in the modern multimodal imaging era

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Diagnostics

Background:

• The electronegative electroretinogram (ERG) reflects inner retinal dysfunction and aids in localizing eye disease anatomically.
• Understanding the frequency and causes of electronegative ERG is crucial for accurate diagnosis and patient management.

Purpose of the Study:

• To determine the incidence and etiological factors of electronegative ERG in a tertiary ophthalmology center.
• To develop a clinical algorithm to aid in the management of patients with electronegative ERG.

Main Methods:

• Retrospective review of ERGs performed between January 2011 and December 2020.
• Analysis of the b:a ratio in dark-adapted recordings (ISCEV standard), including patients with a ratio of ≤1.0.

Main Results:

• Electronegative ERG was identified in 3.1% (139/4421) of patients.
• The primary causes included photoreceptor dystrophy (34.5%), Congenital Stationary Night Blindness (23.7%), and retinal ischemia (12.9%).
• A notable proportion of patients (23%) presented with good vision and normal fundus appearance, and 7.9% had normal multimodal imaging.

Conclusions:

• The frequency of electronegative ERG in this center was 3.1%, with photoreceptor dystrophy being the most common cause.
• Electronegative ERG is valuable for diagnosis, particularly in cases with preserved vision and normal findings on fundus examination or multimodal imaging.
• The study underscores the continued importance of ERG in the current era of advanced multimodal imaging techniques.