Optical coherence tomography changes in Egyptian patients with major depressive disorder

Background Brain imaging of patients with major depressive disorder (MDD) shows evidence of neurodegeneration and inflammation. The retina is believed to be a prolongation of the central nervous system, and therefore optical coherence tomography readings may give an insight into the pathogenesis of MDD. Patients and methods An observational controlled cross-sectional study was performed at Ain Shams University Hospitals from September 2018 to December 2019. Optical coherence tomography was used to compare a group of 30 patients with MDD with a control group of 28 healthy individuals. Measurements recorded were macular thickness, peripapillary retinal nerve fiber layer (RNFL) thickness, and ganglion cell-inner plexiform layer complex (GC-IP) thickness. Results Patients with MDD demonstrated significant macular thinning in all zones of the ETDRS map except the central zone bilaterally, and the inner nasal and inner lower zones in right eye. The peripapillary RNFL thickness of patients with MDD revealed significant thinning in the superior quadrant of both eyes. The GC-IP complex of patients with MDD showed significant thinning in the whole temporal and inner lower nasal subzones of the right eye and the upper nasal and lower temporal subfields of the left eye. Conclusion Patients with MDD showed reduced thickness of the macula, RNFL, and GC-IP. This may indicate that MDD involves an element of neurodegeneration, such as evidenced in gray matter changes.