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Measuring retinas may provide insight into schizophrenia risk, progression

Assessing retinal changes may aid clinicians in assessing schizophrenia risk and disease progression, according to study findings in Schizophrenia Research: Cognition.

“Visual processing impairments are well established in schizophrenia, including abnormalities in contrast sensitivity; various excitatory and inhibitory functions, including those involved in masking and surround suppression; and form and motion processing. There has been little work on color processing to date, but clinical reports indicate frequent descriptions of increased intensity, or alterations in color perception,” Steven M. Silverstein, PhD, of Rutgers Biomedical and Health Sciences, and colleagues wrote.

Steven M. Silverstein

Researchers assessed approximately 170 studies to further investigate associations between retinal function, visual processing and schizophrenia.

Their review indicated multiple, replicated indicators of eye abnormalities among individuals with schizophrenia, including widened small blood vessels in the eye and thinning retinal nerve fiber layers, which is known to be associated with hallucination onset and visual acuity problems among patients with Parkinson’s disease.

Widening small blood vessels, potentially caused by chronic low oxygen supply to the brain, could explain several vision changes and may serve as a marker of disease risk and progression, according to researchers.

Electroretinography results indicated abnormal electrical responses by retinal cells exposed to light, suggesting cellular-level differences in the eyes of patients with schizophrenia. This measure may also be useful in detecting disease progression, according to researchers.

Researchers found that dopamine receptor-blocking medications may negatively affect visual function among patients with schizophrenia. However, they reported this finding requires further investigation.

“The retina develops from the same tissue as the brain. Thus retinal changes may parallel or mirror the integrity of brain structure and function,” Richard B. Rosen, MD, of the New York Eye and Ear Infirmary of Mount Sinai, and Icahn School of Medicine, said in a press release. “When present in children, these changes may suggest an increased risk for schizophrenia in later life. Additional research is needed to clarify these relationships, with the goals of better predicting emergence of schizophrenia, and of predicting relapse and treatment response and people diagnosed with the condition.”

Richard B. Rosen

Within the review, there were no reports of individuals with schizophrenia born blind, suggesting congenital blindness may completely or partially protect against the development of schizophrenia.

“Our analysis of many studies suggests that measuring retinal changes may help doctors in the future to adjust schizophrenia treatment for each patient,” Rosen said. “More studies are needed to drive the understanding of the contribution of retinal and other ocular pathology to disturbances seen in these patients, and our results will help guide future research.” – by Amanda Oldt

Disclosure: Silverstein reports receiving funding from the NIMH, NARSAD, the Jacob and Valeria Langaloth Foundation, the van Ameringen Foundation, the Scottish Rite Schizophrenia Research Program, the New York State Office of Mental Health, the New Jersey Division of Mental Health and Addiction Services, the New England Research Institutes, the Brain Resource Company, the Committee to Aid Research to End Schizophrenia, Janssen Pharmaceutica, Pfizer, Novartis, and Astra-Zeneca. Please see the full study for a list of all other authors’ relevant financial disclosures.