AIM: To explore changes of choroidal blood flow post vitrectomy in idiopathic macular hole(IMH), and to discuss the role of choroidal microstructure changes abnormality in macular hole formation.

METHODS: Totally 56 eyes of 56 patients diagnosed with unilateral IMH were included(2014-05/2015-12). All patients received pars planar vitrectomy, indocyanine green assisted inner limiting membrane peeling combined with intraocular +12%C₃F₈ tamponade. Patients with cataract received phacoemulsification and intraocular lens implantation. Choroidal thicknesses were measured at 9 points before and at 1, 3 and 6mo after the surgery, namely the fovea, 1mm and, 3mm above, below, nasal and temporal to the fovea.

RESULTS: Preoperative SFCT value was 233.43±84.638μm, and at 1, 3, 6mo follow-up SFCT were 242.46±88.199μm, 238.97±89.252μm, and 236.71±88.661μm, respectively. SFCT at 1mo after surgery was significantly increased compared to preoperative thickness(P<0.05). 1, 3, and 6mo after the surgery the choroidal thickness at 3mm below the fovea(ICT_3mm)(179.63±62.941μm, 179.74±65.981μm, 180.80±58.379μm)gradually increased compared with those before the surgery(170.89±57.040μm). However, there was no significant difference between ICT_3mm values at each time point. 1, 3, and 6mo after the surgery the choroidal thickness at 1mm below the fovea(ICT_1mm)(216.31±80.297μm, 214.54±75.693μm, 205.69±68.697μm)compared with those before the surgery(207.37±67.502μm)have statistical significance. Compared 6mo after the surgery with 1mo after the surgery have statistical significance with ICT_1mm values at each time point(P<0.05).

CONCLUSION: SFCT of the study eyes showed a transient increase at 1mo follow up, then gradually returned to the base line. As the macular hole successfully closed, the choroidal thickness didn't not show difference compared with baseline, indicating that the decreasing in choroidal thickness is possibly the cause to the formation of the macular hole, not the results. IMH postoperative choroidal thickness values change by location, which may be due to the oppression by the injected gas in the macular hole surgery.