This retrospective interventional case series from Japan assessed whether preoperative alterations of the retinal pigment epithelial (RPE) in idiopathic macular holes correlated with postoperative functional and morphological changes in the macula. Fifty-nine eyes had preoperative Spectralis OCT using the ‘detailed’ protocol. RPE alterations were defined as a granular structure protruding from the inner border of the RPE line. All patients underwent vitrectomy, ILM peel, air tamponade and three days of face down positioning. Fifty-six patients had combined cataract surgery at the same time as macular hole repair. Eyes were divided into two groups: Group A (n=40) with preoperative RPE alterations and Group B (n=19) without RPE alterations. There were no significant differences in the age, refractive error, AL and distribution of MH stage between the two groups. However, the duration from onset was longer in Group A (P=0.018), the BCVA was significantly better in the eyes of Group B (P=0.014), and the minimum diameter and the base diameter of the MHs were significantly larger in the eyes of Group A (P<0.001 and P<0.001, respectively). There were no significant differences in the BCVA between the two groups at one and three months postoperatively (P=0.218 and P=0.285). However, the BCVA was significantly better in the eyes of Group B at six months (P=0.048). Postoperatively the length of the EZ defect was shorter in Group B at one, three and six months. The ELM defect postoperatively was shorter at one month in Group B, but not at three and six months. The central foveal thickness was not significantly different between the two groups. The authors comment that the RPE protrusions in the preoperative OCT images appear to indicate damage of the RPE and depressed photoreceptor–RPE interactions. Therefore, determining the degree of RPE alterations may help predict the outcome of the surgery and can be used to reassure patients on the prognosis after surgery.