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

In this observational study, patients with idiopathic EMM, undergoing pars plana vitrectomy with Inner Limiting Membrane (ILM) peeling, at the Ophtalmology Clinic of IRCCS Policlinico San Matteo, are enrolled.

The clinical diagnosis of EMM is based on indirect binocular ophthalmoscopy with a + 90 D no-contact lens (Volk Optical Inc., Ohio, USA) and on the SD-OCT examination (see below) which revealed an increase in macular volume associated with optically hyperreflective epiretinal echoes due to the presence of a membrane.

Since several pathologies may induce changes of the macula bioelectrical responses, and their presence may represent potential confounding factors, patients enrolled in the present study were selected from a large EMM cohort of patients after exclusion of presence of dense lens opacities, ocular hypertension or glaucoma, diabetic retinopathy, drusen and age-related macular disease, other general diseases such as systemic hypertension, diabetes, connective tissue or neurological diseases.

Based on that reported by Falkner-Radler et al. , our patient are divided into 2 groups in relationship to the integrity of IS/OS junction: a group in which an intact IS/OS junction was identified by SD-OCT examination (EMM-I Group) and a group in which a disrupted IS/OS junction was observed by SD-OCT examination, EMM-D Group.

Evaluation of photoreceptor status is performed on the central part of the 1.5 mm of two perpendicular scans centered on the fovea. The intact IS/OS junction is identified as a continuous hyperreflective line ; the disrupted IS/OS junction is identified as interruptions of the normal hyperreflective line. Classification was assessed by the agreement of two different grader. In case of disagreement a third assessment was obtained by another expert grader.