Retinal changes in bipolar disorder as an endophenotype candidate: Comparison of OCT-detected retinal changes in patients, siblings, and healthy controls

Optical coherence tomography (OCT) is a non-invasive imaging technique that detects retinal changes reflecting neurodegeneration. In recent studies in patients with bipolar disorder (BD) abnormal OCT findings have shown. In this study, we aimed to investigate the retinal changes in BD patients and their healthy siblings (HS) by comparing them with the healthy control (HC) group and to explore these findings as potential endophenotype candidates. 31 patients with BD, 31 age-matched HSs and 46 HCs were included and peripapillary retinal nerve fiber layer (RNFL), ganglion cell layer (GCL)+inner plexiform layer (IPL) and macular volume (MV) thicknesses were measured by OCT. The relationship between disease severity parameters, functionality and OCT measurements in the patient group was also investigated. In results, the mean RNFL thicknesses did not differ between groups. All GCL+IPL thicknesses were found to be significantly lower in the patient and sibling groups compared to the HCs. GCL+IPL thicknesses were significantly correlated with functionality of patients and severity of the disorder. Our findings suggest that analysis of retinal layers with OCT may be a beneficial indicator to show neuronal changes in BD and GCL+IPL may be a suitable endophenotype candidate.