Introduction: Findings of gray and white matter found in neuroimaging studies in bipolar disorder (BD) patients support the neurodegenerative processes that play a role in the pathophysiology of the disease. Limitations such as low image resolution, cost, and patient burden in brain imaging techniques have led researchers to use optical coherence tomography (OCT), a high-resolution, easy-to-apply and non-invasive retinal imaging tool to identify markers of brain pathology. In a limited number of studies with OCT, thinning of the retinal layers has been found in bipolar disorder patients compared to healthy controls, and it has been suggested that these findings may represent the destruction of the central nervous system. In this study, we aimed to identify potential biomarkers by examining a detailed analysis of OCT findings in bipolar patients and their relationship with diffusion tensor imaging (DTI) parameters. Method: Fifty patients diagnosed with bipolar disorder according to DSM-5 criteria and 50 healthy controls matched with these patients in terms of age and gender were included in the study. Hamilton Depression Rating Scale (HAM-D) and Young Mania Rating Scale (YMRS) were applied to the participants. By performing full-layer retinal analysis of the participants through OCT, macula, choroid (CH) and total retinal thickness (RET) measurements as well as all retinal layers Retinal nerve fiber layer (RNFL), Ganglion cell layer (GCL), Inner plexiform layer (IPL), Each layer by measuring nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigment epithelium (RPE), inner retinal layer (IRL), outer retinal layer (ORL), photoreceptor layer (PHRS) Central (S), nasal (N), temporal (T), upper (U), down (D) quadrants were evaluated separately. VentroLateral Preoptic Nucleus (VLPN), Olivary Pretectal Nucleus (OPN), Suprachiasmatic Nucleus (SCN), Retinal Hypothalamic Tract (RHT), Hypothalamus, Superior Longutidunal Fascicle (SLF), Inferior Longutidunal Fascicle (SLF) FA / ADC / MD / RD values ​​were measured for (corpus / splenium / Genu), Cingulum, Unsinat fascicle (UF) and optical radiation (OR). Results: In our study, there was no difference in GCL, INL and OPL thickness between the patient group and the control group. Right macula, CH, CH (N / T / mean), RET (S / U), RNFL-S, IPL(S/D), ONL (T / S), RPE (U / D), IRL-S, ORL (T / S / N / U / D), PHRS (T / S / U) measurements were found to be significantly thinner in the patient group. In terms of DTG parameters, hypothalamus, SLF, CC corpus and splenium in the patient group and ILF FA measurements were found to be lower in the patient group, while the ADC / mD / RD measurements were found to be significantly higher in the RHT and CC splenium (p0.05). In the correlation of retinal parameters and DTG parameters, IPL-D and ORL-N quadrants correlated with KK splenium and corpus FA, while a significant correlation was found between the ORL-U quadrant and the KK Genu FA. Conclusion: Contrary to the literature, a widespread thinning of the retinal layers was found in patients with bipolar disorder in our study. Thinning has been demonstrated for the first time, especially in ORL and PHRS layers. Our DTG findings showed an increase in ADC / mD / RD in RHT in addition to supporting neurodegeneration occurring in various white matter pathways in accordance with the literature. Our study is the first to examine the correlation of retinal layer thicknesses with DTG parameters. Our findings support the assumption that OCT parameters reflect central neurodegeneration. Longitudinal and comparative studies with different patient groups on retinal changes in neuropsychiatry and applying new analysis methods to these data will be beneficial to accelerate clinical and scientific discovery by increasing predictive analytical values for biomarker development of retinal variables.