Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography Estimation of Retinal Nerve Fibre Layer, Subfoveal Choroidal Thickness and Macular Thickness in Schizophrenics vs Healthy Controls

Abstract Objectives: To assess retinal nerve fibre layer (RNFL) thickness, macular volume, macular thickness, and subfoveal choroidal thickness (SFCT) in chronic schizophrenia patients by using Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography (EDI-SD-OCT) and compare them with healthy controls. Methods: This Hospital based prospective comparative study included 51 patients diagnosed with chronic schizophrenia (>2 years) and 51 age-matched controls. All patients underwent ophthalmic and EDI-SD-OCT evaluation. RNFL thickness (seven quadrants), macular thickness (ETDRS- Early Treatment Diabetic Retinopathy Study grid), and SFCT measurements analysed. Data was compared using independent t-tests and Pearson’s correlation ( P < 0.05 considered significant). Results: Mean age of participants was 39.6 ± 8.3 years, with no significant differences in age or gender between groups. Schizophrenia patients exhibited significant thinning in the global, superotemporal, inferotemporal, superonasal, nasal and temporal quadrants, while the inferonasal quadrant showed no significant difference. Macular volume was significantly decreased in patients (7.70 vs. 8.38; P = 0.0005), with notable thinning across all inner macular subfields, including the central fovea. SFCT was significantly lower in schizophrenia patients (right eye: 232.7 μm vs. 280.3 μm; left eye: 229.5 μm vs. 273.0 μm; P = 0.0005 for both). Conclusions: Chronic schizophrenia patients exhibit significant thinning of the RNFL, macular volume, macular thickness and SFCT compared to healthy controls. These structural retinal and choroidal alterations, particularly the reduction in SFCT, may serve as non-invasive biomarkers of neurodegeneration and microvascular dysfunction in schizophrenia.