Nonsedated handheld electroretinogram as a screening test of retinal dysfunction in pediatric patients with nystagmus

Purpose To assess the feasibility, sensitivity, and specificity of nonsedated handheld cone flicker electroretinogram (ERG) as a screening tool to detect retinal dysfunction in children with nystagmus. Methods Pediatric patients at a tertiary referral center from December 2015 to July 2016 were enrolled and placed into three age-matched groups: normal, nystagmus with a retinal dystrophy, and nystagmus without a retinal dystrophy. Unsedated 30 Hz cone flicker ERG responses were obtained using a handheld device (RETeval) from both eyes of each patient using skin electrode sensors after pupillary dilation. Results A total of 71 children were enrolled; amplitudes and implicit times were successfully obtained in 65 (92%): 31 (mean age ± SD, 5.6 ± 2.7 years; range, 1-12 years) without nystagmus and 34 with nystagmus. Nystagmus patients were grouped by those with (n = 15; mean age, 8.5 ± 4.5 [range, 2-17 years) and without (n = 19; mean age, 4.3 ± 3.0 [range, 6 months-10 years]) a retinal dystrophy. The patients with retinal dystrophies had significantly smaller amplitudes and prolonged or nonmeasurable implicit times than the other two groups (P < 0.001). Among nystagmus patients, amplitude was able to discriminate between those with and without retinal dystrophies with area under curve of 0.986 (SE = 0.016; P < 0.001). An amplitude <5 μV in combination with an implicit time of >33 ms warrants further evaluation. Conclusions Unsedated handheld cone flicker ERG is a feasible screening test that effectively detects retinal dysfunction in children with nystagmus. In conjunction with clinical findings, the test helps reduce the need for sedated ERG in children.