Novel mesopic electroretinography protocol for assessment of pediatric visual impairment

Abstract

Purpose : Standard electroretinography (ERG) protocol recommended by the International Society for Clinical Electrophysiology of Vision (ISCEV) is not fully applicable in children due to the time-consuming process, child‘s poor cooperation, and the potential side effects of general anesthetics. Modified fast and comfortable protocols are required in children to accurately confirm the presence of hereditary or degenerative retinal disorders. In this retrospective case series study we evaluated the modified mesopic ERG protocol with minimal discomfort and risk for the assessment of visually-impaired children.

Methods : The registered documents of children, aged less than 10 years, referred to Farabi Eye Hospital for ERG testing since 2010 to 2020 were reviewed. ERGs had been carried out under novel modified protocol with light Sevoflurane sedation, and the Burian-Allen type active electrode in a dimly lit room (0.55 lux) “mesopic luminance”. The eyes were stimulated after 5-minute mesopic adaptation with only 2 types of stimuli: a flash white 10 cd-s/m² stimulus followed by flicker 3.0 cd-s/m² stimulus, instead of the 5 conventional stimuli described in ISCEV protocol. The final ocular diagnosis was made based on clinical examination and ERG test results.

Results : Within 10 years, 955 patients met the inclusion criteria; the mean presenting age was 46.5 ± 38.2 months, and 286 (22.82%) patients had neurological problems. Among children referred for diagnostic ERG, 45% had normal ERG and 54.3% were diagnosed with retinal dystrophy/dysfunction. Several case examples recorded using the mesopic ERG are illustrated (Figure). Rod-cone dystrophy (160 subjects, 19%), Leber’s congenital amaurosis (126 subjects, 15%), and cone-rod dystrophy (92 subjects, 11%) were the most common diagnoses.

Conclusions : Modified mesopic ERG technique, with a 5-minute adaptation protocol, provides mixed rod-cone and mesopic flicker responses which might be helpful in screening visually impaired children.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.