Choroidal structural changes following vitrectomy performed with phacoemulsification in unilateral idiopathic epiretinal membrane

BACKGROUND: This study aims to determine the influence of vitrectomy combined with macular epiretinal membrane dissection and internal limiting membrane (ILM) peeling and phacoemulsification on choroidal vasculature in patients with unilateral idiopathic epiretinal membrane (IERM) and concurrent cataract using optical coherence tomography (OCT). METHODS: This retrospective study included 26 eyes of 26 patients (8 males and 18 females) with unilateral IERM without vitreomacular traction (VMT) (group 1) and the patients’ fellow eyes (n = 26, group 2). Three-port 25-G pars plana vitrectomy (PPV) combined with macular epiretinal membrane dissection and ILM peeling and phacoemulsification was performed on all patients. The comprehensive ophthalmologic examinations of all patients involved OCT measurements at every visit before and after surgery, and the choroidal thickness (CT), central macular thickness (CMT) and choroidal vascularity index (CVI) were calculated. RESULTS: The mean age of the IERM patients was 66.58 ± 7.06 years. Postoperatively, best corrected visual acuity (BCVA) was significantly greater than baseline (P = 0.023). The CVI of the IERM eyes was significantly lower (P < 0.01) than that of the fellow eyes at baseline. The subfoveal CT in the IERM eyes was lower than that in the fellow eyes (P = 0.023), but there was, no significant difference in the average CT between the two groups at baseline (P = 0.071). In eyes with IERM, the CVI significantly increased at 1 week, 1 month (P < 0.001), and 3 months (P = 0.049) postoperatively, the subfoveal CT was markedly thickened 1 month after surgery (P = 0.001), the temporal 3 mm and nasal CT significantly increased at 1 week and 1 month postoperatively (P = 0.041, P = 0.022 for temporal 3 mm; P < 0.001, P = 0.047 for nasal 1.5 mm; P = 0.01, P = 0.001 for nasal 3 mm), and only the temporal 3 mm CT increased significantly at 3 months postoperatively (P = 0.017). The baseline CMT of the IERM eyes was significantly thicker than that of the fellow eyes (P < 0.001). CMT significantly decreased at 3 months postoperatively in IERM eyes(P = 0.033). CONCLUSIONS: The increase in the CVI in the IERM eyes without VMT after combined PPV with ILM peeling and phacoemulsification persists for at least 3 months.