To evaluate the anatomic features of the photoreceptor inner/outer segment (IS/OS) junction before and after surgery by spectral-domain optical coherence tomography in patients undergoing idiopathic epiretinal membrane (ERM) surgery and to correlate these features with the functional outcomes.

Prospective, cohort study.

We prospectively studied 45 eyes of 45 patients with idiopathic epiretinal membrane who had a preoperative visual acuity of 20/32 or less and were scheduled to undergo transconjunctival 25-gauge vitrectomy. The patients were divided into 2 groups based on the preoperative structural integrity of the IS/OS junction: the intact IS/OS junction group and the disrupted IS/OS junction group. Changes in the IS/OS junction and best-corrected visual acuity were compared between 2 groups before and at 3, 6, and 12 months after surgery.

A total of 45 patients were recruited for this study. There were 34 eyes with an intact IS/OS junction (group 1) and 11 eyes with a disrupted or irregular IS/OS junction (group 2), as determined before surgery. Significantly better postoperative best-corrected visual acuity was seen in group 1 as compared with that in group 2 at 3, 6, and 12 months after the surgery (P < .001). Significant improvement of visual acuity was also seen in group 1 when compared to group 2 (P < .05). Of the 34 eyes in group 1, 17 (50%) showed disruption of the IS/OS junction at 3 months after surgery, although this disruption was only transient and resolved completely by 12 months after the surgery. However, none of the eyes from group 2 showed a normal appearance of the IS/OS junction at any time point during the study period of 1 year.

The IS/OS junction can recover in eyes with preoperative intact IS/OS junction as assessed over a follow-up period of 1 year after surgery. Preoperative integrity of the IS/OS junction may be an important prognostic factor for better visual recovery and better improvement of the postoperative best-corrected visual acuity after epiretinal membrane surgery.