Comparison of Non-Sedated Cone Flicker ERG Screening Test and Conventional ERG under Anesthesia in Children
Carla J. Osigian, MD; Sara F. Grace, MD; William J. Feuer, MS; Mehdi Tavakoli, MD; Piangporn Saksiriwutto, MD;
Kara M. Cavuoto, MD; Hilda Capo, MD; Byron L. Lam, MD
Bascom Palmer Eye Institute
900 NW 17th St, Miami, FL 33136
Introduction: Electroretinography (ERG) is limited in children by cost, availability, and general anesthesia (GA) risks. We prospectively evaluated a handheld ERG device (RETeval) as a cone dysfunction screening tool and compared it to conventional ERG under GA.
Methods: Patients scheduled for conventional ERG under GA underwent 3 tests: 1) RETeval standard 30-Hz cone flicker ERG using skin electrodes prior to GA, 2) E3 Diagnosys conventional complete standard protocol full-field ERG using bipolar contact lens electrodes and handheld stimulus under GA, 3) repeat RETeval testing under GA. The 30-Hz cone flicker amplitudes and implicit times obtained with the 3 methods were compared. Negative (NPV) and positive (PPV) predictive values were calculated using a 5uV amplitude cut-off.
Results: Of 30 children included, 18 presented abnormal results on conventional ERG. RETeval amplitudes were smaller before GA (mean difference -42.24uV, SD 45.30) and under GA (-37.10uV, SD 44.45) than the Diagnosys. RETeval implicit times were shorter prior to GA (-1.06ms, SD 2.83) and longer under GA (1.28ms, SD 4.12) than the Diagnosys. RETeval amplitude values were lower (-3.05uV, SD 6.82) and implicit times were shorter (-2.25uV, SD 3.28) prior to GA than under GA. For the awake RETeval PPV=85% and NPV=90%.
Discussion: The 30-Hz cone flicker using the RETeval has smaller responses than the conventional ERG under GA, likely in part due to differences between electrodes. However, it is a feasible screening test for detecting cone dysfunction in children.
Conclusion: When responses of the RETeval test are impaired, a conventional ERG using full international protocol should be performed.
References: 1. Nakamura N, Fujinami K, Mizuno Y, Noda T, Tsunoda K. Evaluation of cone function by a handheld non-mydriatic flicker electroretinogram device. Clinical ophthalmology (Auckland, NZ). 2016;10:1175-85.
2. Grace S, Lam BL, Feuer WJ, Osigian CJ, Cavuoto KM, Capo H. Non-sedated handheld electroretinogram as a screening test of retinal dysfunction in pediatric patients with nystagmus. AAPOS Meeting 2017.
3. Lam BL. Full-field electroretinogram. In: Lam BL, editor. Electrophysiology of vision- clinical testing and applications. 1st ed. Boca raton, FL: Taylor and Francis; 2005. p. 2-64