In a recent analysis of patients with schizophrenia spectrum disorder (SSD), reduced single retinal layer thickness was found using optical coherence tomography (OCT) measurements. 26 patients with schizophrenia or SSD, and 23 age-and sex-match healthy controls were examined to derive a single-layer analysis of both retinas. Researchers found:
- Compared to the control group, SSD patients showed reduced thickness and volume measurements for nearly all retinal layers.
- Differences reached significance for macular volume, macular thickness, retinal nerve fiber layer (RNFL), and inner nucleiform layer (INL).
- There was a significant correlation between the duration of illness and the total volume of the RNFL.
Schönfeldt-Lecuona C, Kregel T, Schmidt A, et al. Retinal single-layer analysis with optical coherence tomography (OCT) in schizophrenia spectrum disorder. [Published online ahead of print April 11, 2019]. Schizophr Res. doi:10.1016/j.schres.2019.03.022.
The concept of schizophrenia spectrum disorder as a neurodegenerative condition has been the focus of considerable research, including brain imaging which in some studies, has found volume reduction consistent with a neurodegenerative process. The retina of the eye can provide a "window" into brain processes that reflect not just local changes, but also a global view of neurodegenerative processes. Optical coherence tomography (OCT) is a high-resolution imaging technique that provides quantification of retinal layers. Results of the study by Schonfeldt and colleagues provide evidence that structural brain changes seen in patients with schizophrenia are also observable in the retina. Findings provide an intriguing view of the different components of the nervous system that are abnormal in schizophrenia and which may help shed light on the variable presentation of this disorder across the life-span. —Martha Sajatovic, MD, Professor of Psychiatry and of Neurology; Willard Brown Chair in Neurological Outcomes Research; Director, Neurological and Behavioral Outcomes Center, University Hospitals Cleveland Medical Center; Case Western Reserve University School of Medicine.