Abstract
Schizophrenia is a complex disorder that is diagnosed mainly with clinical observation and evaluation. Recent studies suggest that many people with schizophrenia have abnormalities in the function of the N-methyl-d-aspartate receptor (NMDAR). The retina is part of the central nervous system and expresses the NMDAR, raising the possibility of the early detection of NMDAR-related schizophrenia by detecting differences in retinal function. As a first-step, we used two non-invasive outpatient tests of retinal function, the photopic negative response (PhNR) of the light-adapted flash-electroretinogram (PhNR-fERG) and the pattern ERG (PERG), to test individuals with schizophrenia and controls to determine if there were measurable differences between the two populations. The PhNR-fERG showed that males with schizophrenia had a significant increase in the variability of the overall response, which was not seen in the females with schizophrenia. Additionally at the brightest flash strength, there were significant increases in the PhNR amplitude in people with schizophrenia that were maximal in controls. Our results show measurable dysfunction of retinal ganglion cells (RGCs) in schizophrenia using the PhNR-fERG, with a good deal of variability in the retinal responses of people with schizophrenia. The PhNR-fERG holds promise as a method to identify individuals more at risk for developing schizophrenia, and may help understand heterogeneity in etiology and response to treatment.