An Optical Coherence Tomography Study that Supports the Neurovascular Basis of Schizophrenia Disease

OBJECTIVES: Spectral domain optical coherence tomography (SD-OCT) is a non-­penetrating, quick, and practical device which enables measurement of the chorioretinal layers. In this study, our purpose was to investigate the retinal nerve fiber layer (RNFL) and choroidal thickness in schizophrenia patients, using SD-OCT, and compare the ­findings with those of the control group. METHODS: For the study, 44 patients with a diagnosis of schizophrenia, and 41 age- and gender- matched healthy controls were enrolled. Both eyes of each participant were ­evaluated. RNFL was measured and analyzed automatically with optical coherence tomography. Scans for choroidal thickness were obtained with the enhanced depth imaging mode of the SD-OCT device and measured manually. RESULTS: The average age of schizophrenia patients was 47.82, and it was 45.5 for the control group. The mean illness duration of the patients was 24.79 years. According to the results of this study, all choroidal measures (nasal, subfoveal, and temporal) of both eyes, and the RNFL thickness of schizophrenia patients, were significantly thinner than that of healthy controls. The chorioretinal measures of both eyes were similar. The results showed that a weak negative correlation was present between illness duration and choroidal diameter. CONCLUSION: In addition to demonstrating the thinning of RNFL in schizophrenia patients, as frequently reported in the literature, the results of this study show, for the first time, that choroidal thickness is considerably decreased in schizophrenia patients compared to the healthy controls, using SD-OCT. Keeping in mind that the choroid is a vascular layer, these results support the neurovascular hypothesis of schizophrenia.