Background The classical theory from Gass holds that idiopathic macular hole (IMH) is due to the dragging of vitreous cortex in the tangent direction on the macular region,while spectral domain OCT (SD-OCT)studies found that the diameters of inner segment/outer segment (IS/OS) absence (DIOA) region was closely associated with vision ability of IMH patients.Enhanced depth imaging (EDI) is thought to be a new method to study the relation between DIOA and subfoveal choroidal thickness (SFCT) ,but there are few relevant reports.Objective This study aimed to observe the correlation between photoreceptor IS/OS junction and SFCT before and after vitrectomy in IMH by EDI SD-OCT.Methods Forty unilateral IMH patients were enrolled in Affiliated Foshan Hospital of Southern Medical University from June 2011 to June 2013.Vitrectomy (23G) was performed on the patients by the same operator.EDI mode of SD-OCT was used to measure DIOA and SFCT in horizontal direction before and 6 months after surgery.The relationship between DIOA and SFCT was evaluated using Pearson linear correlation analysis.Written informed consent was obtained from each patient before medical assessment.Results IMH was anatomically closed after vitrectomy in 34 eyes with the closure rate 85％.The mean DIOA was (1 280±753) μm in preoperation, which was significantly higher than (656 ± 322) μm in postoperation (t =4.989, P =0.000).The mean SFCT was (130±43)μm in preoperation,showing a slight reduce in comparison with (140±38)μrn in postoperation, but there was not statistical significance between them (t =-1.407, P =0.175).Negative correlations were found between DIOA and SFCT in both preoperation and postoperation (preoperation:r=-0.748 ,P=0.000;postoperation: r=-0.686,P =0.001).Conclusions The alteration of DIOA shows a negative correlation with SFCT in IMH eyes,suggesting a contributing role of the choroid in the change of photoreceptors of IMH.