Polarimetric entropy mapping of retinal pigment epithelium in full-thickness macular hole by polarization-sensitive OCT

BACKGROUND: This study is aimed to evaluate retinal pigment epithelium (RPE) entropy in eyes with full-thickness macular hole (FTMH) using polarization-sensitive optical coherence tomography (PS-OCT). METHODS: Patients diagnosed with treatment-naïve FTMH who underwent pars plana vitrectomy with internal limiting membrane peeling were included. Ophthalmologic examinations, including visual acuity (BCVA), swept-source OCT (SS-OCT), and PS-OCT, were performed. Polarimetric entropy (PE) of RPE was assessed using PS-OCT and compared with affected and fellow eyes and before and after surgery. RESULTS: Fourteen eyes of 14 patients were included (64.5 ± 5.84 years). All eyes achieved complete FTMH closure following the surgery. PE value within the central foveal area (< 200 μm from the foveal center) was significantly lower than that in fellow eyes (p = 0.013), whereas PE in the area surrounding FTMH was significantly higher (p = 0.0402). The interocular difference in foveal PE (affected eye minus fellow eye) was significantly and negatively correlated with baseline BCVA (p = 0.0445). Postoperatively, PE in the surrounding area significantly decreased, whereas foveal PE did not change. Eyes without EZ recovery exhibited significantly greater baseline foveal PE reduction than those with EZ recovery (p = 0.0053). CONCLUSIONS: These findings suggest two spatially distinct RPE responses in FTMH: decreased entropy in the foveal area and increased entropy in the surrounding region. Foveal RPE-PE quantified by PS-OCT is associated with EZ recovery and may reflect postoperative structural outcomes.