Comparing retinal changes measured by optical coherence tomography in patients with schizophrenia and their siblings with healthy controls: Are retinal findings potential endophenotype candidates?

Aim: The aim of our study is to examine whether differences in retinal structure may reflect endophenotypes for schizophrenia by comparing thicknesses of retinal layers between patients with schizophrenia, their unaffected siblings, and healthy control groups and investigating the relationship between OCT findings and disease parameters.

Material And Methods: 46 patients with schizophrenia, their 46 healthy siblings, and 46 age and gender-matched healthy controls were enrolled in the study and underwent spectral domain OCT (examinations to assess differences in peripapillary retinal nerve fiber layer (RNFL) thickness, ganglion cell layer (GCL)+ inner plexiform layer (IPL) thicknesses and macular volumes (MV) in both eyes). Clinical variables were also recorded in the patient group.

Results: There was no difference between the groups in terms of RNFL thicknesses. The GCL+IPL thicknesses of the siblings are between the patients and controls but according to post hoc comparisons the GCL+IPLs of the patients were only thinner than controls. Additionally, MVs were significantly lower in the patient group compared to the sibling group. There was no correlation between any clinical parameters and the GCL+IPLs of all groups, however there were some correlations between RNFL and clinical features especially in the patients group.

Conclusion: GCL+IPL values do not seem to be affected by the disease parameters or the factors like body mass index or nicotine use. On the other hand, further studies are needed to determine whether GCL+IPL could be an endophenotype candidate.