Choroidal thickening and temporal RNFL thinning in TRD patients: no structural retinal changes following TMS treatment.

Treatment-resistant depression (TRD) is a particularly challenging subset of major depressive disorder (MDD), often unresponsive to conventional antidepressants. Transcranial magnetic stimulation (TMS) is recognized as an effective and reliable alternative treatment for patients with TRD. However, the effects of long-term functional changes induced by TMS treatment on retinal structures remain unclear. In this prospective study, a total of 32 patients with TRD were evaluated for retinal nerve fiber layer (RNFL), macula and choroidal thickness changes before and after TMS treatment. Patients received either intermittent theta burst stimulation (iTBS) or repetitive TMS (rTMS) targeting the left dorsolateral prefrontal cortex. The protocol consisted of five days a week, with a total of 20 daily sessions over four weeks. Retinal measurements, including central macula thickness, RNFL, and choroidal thickness, were conducted using Spectral Domain Optical Coherence Tomography (SD-OCT) and enhanced depth imaging (EDI) mode. TRD patients had thicker choroids in both eyes and reduced left eye temporal RNFL thickness compared to healthy controls (p values<0.05). TMS treatment did not produce significant changes in RNFL, macula, or choroidal thicknesses overall (p values>0.05). TRD patients exhibited significant changes in choroid and RNFL thickness, as measured by OCT imaging. TMS treatment did not result in significant alterations in these retinal measurements overall, but some retinal measurements may be affected under specific conditions such as gender, antidepressant drug type, and additional drug use. Further research focusing on these subgroups is necessary to better understand the effects of TMS on retinal structures.