The photopic negative response in autism spectrum disorder

Clinical relevance: To ascertain if the photopic negative response of the electroretinogram is different in autism spectrum disorder as a potential clinical marker. Background: Visual function can be atypical in autism spectrum disorder and structural imaging of the ganglion cell layers has been reported to differ in these individuals. Therefore, we sought to investigate if the photopic negative response of the full field electroretinograms, a measure of ganglion cell function, could help explain the visual perceptual differences in autism spectrum disorder and support the structural changes observed. Methods: Participants (n = 55 autism spectrum disorder, aged 5.4–26.7 years) and control (n = 87, aged 5.4–27.3 years) were recruited for the study. Full-field light-adapted electroretinograms using a Troland protocol with 10 flash strengths from −0.367 to 1.204 log photopic cd.s.m⁻² were recorded in each eye. The photopic negative response amplitudes at Tmin and at t = 72 ms were compared between groups along with the a- and b-wave values. Results: There were no significant interactions between groups for the Photopic Negative Response measures of amplitude or time (p > 0.30). There was a group interaction between groups and flash strengths for the b-wave amplitude as previously reported (p < 0.001). Conclusion: The photopic negative response results suggest that there are no significant differences in the summed retinal ganglion cell responses produced by a full-field stimulus.