PURPOSE:To evaluate the anatomy of idiopathic macular hole (IMH) using Optical Coherence Tomography (OCT) and to construct a prognostic index that can be correlated with the visual outcomes and the anatomical closing. METHODS:Prospective study, in which 22 eyes with IMH had been evaluated through OCT in the daily postoperative period of IMH surgery. The Prognostic of Macular Hole Index (PMHI) was created which was correlated with the anatomical result and the postoperative visual acuity (VA) six months after surgery. RESULTS:Sixteen eyes (72.7%) got anatomical closing at the end of six months of follow-up. On analysis of PMHI, there was significant difference between group 1 (open MH) and group 2 (closed MH) (p=0.0018). The risk for failure of anatomical closing is 11 times greater when the diameter of the internal base is over 600 microm or IPBM is less than 0.6 (p=0.0495). Regarding final VA, it was observed that the IPBM had a significant negative correlation with AV (p=0.001). CONCLUSIONS:IPBM showed to be the best predictor of anatomical closing and postoperative visual acuity among the studied variables. It predicted 41% of the postoperative final visual acuity, leading us to believe that other factors, such as the time of history and the degeneration of photoreceptors in these older BM, can be involved in the visual outcomes.