Abstract： Objective:To investigate the choroidal blood flow and visual function in idiopathic macular hole.Methods:In this prospective study, fundus structure and visual function in 22 eyes with macular hole and their fellow eyes and 16 normal eyes were assessed. The best corrected visual acuity and retinal sensitivity were detected by the EDTRS visual chart and MP1. The choroidal blood flow was observed by optical coherence tomography angiography. The choriocapillary blood flow density was measured using MatLab. The thickness of the choroid and the aperture size of macular hole were measured using enhanced depth imaging mode of Heidelberg optical coherence tomography.Results:The best corrected visual acuity and retinal sensitivity of macular hole eyes [1.02±0.20 and (13.03±2.91) dB] were significantly lower than fellow eyes [0.15±0.11, t=17.019, P<0.001 and (17.25±2.03) dB, t=-4.085, P<0.001] and normal eyes [0.04±0.05, t=21.736, P=0.001 and (16.63±2.89) dB, t=-3.134, P=0.004]. The blood flow area of choroidal capillaries in macular hole eyes [(1.33±0.29) mm 2] was significantly lower than fellow eyes [(1.98±0.13) mm 2; t=-9.424, P<0.001] and normal eyes [(1.93±0.12) mm 2; t=-8.707, P<0.001]. The paracentral blood vessel density of the choroid capillary layer in macular hole eyes (48.91%±10.12%) was significantly lower than fellow eyes (58.27%±6.18%; t=-3.502, P=0.001) and normal eyes (55.20%±2.12%; t=-2.830, P=0.020). The subfoveal choroidal thickness of macular hole eyes [(188±21) μm] was significantly lower than fellow eyes [(217±36) μm; t=-3.672, P=0.002] and normal eyes [(229±25) μm; t=-3.304, P<0.001]. The basic diameter of macular hole eyes was correlated with the blood vessel density ( r=-0.584, P=0.004), the subfoveal choroidal thickness ( r=-0.511, P=0.015) and the retinal sensitivity ( r=-0.432, P=0.044). The retinal sensitivity was correlated with the blood vessel density ( r=0.450, P=0.035) and the subfoveal choroidal thickness ( r=0.429, P=0.046). Conclusions:The retinal sensitivity and fundus blood perfusion of idiopathic macular hole was decreased, and the thickness of paracentral choroid in the contralateral eye tended to become thinner. The reduced visual function in eyes with macular hole may be associated with the decreased choroidal thickness and worse blood flow of fundus microcirculation.