Surgery for Idiopathic Epimacular Membrane: Morpho-Functional Outcomes Based on the Preoperative Macular Integrity of the Photoreceptoral Junction. A Prospective Pilot Study.

This study aimed to evaluate whether the preoperative integrity of the inner segment (IS) and outer segment (OS) photoreceptoral junction may influence the postoperative visual acuity, the macular morphology [assessed by spectral domain optical coherence tomography (SD-OCT)], and macular function (evaluated by multifocal electroretinogram, mfERG) in patients with idiopathic epimacular membrane (EMM) followed up for 6 months. In this observational prospective study, 18 patients with EMM (mean age 72.5 ± 6.87 years) were enrolled. They were divided into two groups according to the preoperative integrity of the SD-OCT IS/OS junction: the EMM-I group with an intact IS/OS junction (11 patients, mean age 72.75 ± 3.49 years, providing 11 eyes) and the EMM-D group with a disrupted IS/OS junction (7 patients, mean age 70.86 ± 10.79 years, providing 7 eyes). For each enrolled patient, visual acuity (VA), mfERG, and SD-OCT were assessed at baseline (preoperative) and after 1, 3, and 6 months of follow-up after surgical treatment for EMM (pars plana vitrectomy with EMM removal and internal limiting membrane peeling). During the whole follow-up, VA was significantly increased in EMM-I eyes and unmodified in EMM-D eyes. In both groups, mfERG responses were not significantly different and not related to VA differences. In EMM-I eyes a significant reduction of central retinal thickness (CRT) was observed; however, it was not correlated with VA changes. In EMM-D eyes CTR was not significantly reduced, whereas macular volume was significantly reduced. These changes were significantly related to the corresponding differences in VA. Our results suggest that the preoperative evaluation of the integrity of the IS/OS junction is relevant for postoperative outcomes. The recovery in VA was higher in EMM-I eyes than in EMM-D eyes. Postoperative recovery was not associated with morphology of the outer retina (photoreceptor and outer nuclear layer) and the function of preganglionic elements.