Multiple retinal anomalies in schizophrenia.

INTRODUCTION: In addition to being a critical component of the visual system, the retina provides the opportunity for an accessible and noninvasive probe of brain pathology in neuropsychiatric disorders. Several studies have reported various retinal abnormalities in schizophrenia, some primary and others iatrogenic. There is now increasing evidence supporting the existence of retinal anomalies in schizophrenia across structural, neurochemical and physiological parameters. Here, we review the types of retinal pathology in schizophrenia and discuss how these findings may provide novel insights for future research into the neurodevelopmental neurobiology of this syndrome, and possibly as useful biomarkers.

METHODS: Using the keywords schizophrenia, retina, pathology, electroretinogram (ERG), and/or optical coherence tomography (OCT) on PubMed, all studies using the English language within 30years were reviewed. Methods were examined, and common themes were identified, tabulated, and discussed.

RESULTS: We classified the reports of retinal pathology into primary and secondary. The major secondary retinal pathology is related to the iatrogenic effects of a once widely prescribed first generation antipsychotic (thioridazine), which was found to be associated with retinal pigment deposits, decreased visual acuity, and suppression of dark adapted ERG responses. The primary retinal findings were obtained via different measures primarily using ERG, OCT, and microvascular imaging. The most consistent findings were 1) decreased ERG wave amplitudes, 2) reduced macular volume, 3) thinning of retinal nerve fiber layer, and 4) widened venule caliber.

CONCLUSION: The abnormal pathobiological findings of the retina in schizophrenia may represent an important avenue for elucidating some of the neurodevelopmental aberrations in schizophrenia. The well replicated retinal anomalies could serve as biomarkers for schizophrenia and perhaps an endophenotype that may help identify at-risk individuals and to facilitate early intervention.