Features and surgical outcome of retinal nerve fiber layer alterations associated with epiretinal membrane

In this study, the authors aimed to investigate structural abnormalities in the retinal nerve fiber layer (RNFL) using spectral-domain optical coherence tomography (SD-OCT) and study the surgical outcomes in eyes with such alterations by comparing ultrastructure findings of the surgically excised epiretinal membrane (ERM) and inner limiting membrane (ILM) in patients with idiopathic ERM.

Vitreous surgery was performed on four eyes with idiopathic ERM, of which three had columnar alterations of the nerve fiber layer. The ERM and ILM were dissected and removed, and ultrathin sections were analyzed and imaged completely by using electron microscopy. All the patients underwent a comprehensive ophthalmologic examination, including SD-OCT, fundus-monitoring microperimetry, and red-free scanning laser ophthalmoscopic imaging.

Preoperatively, SD-OCT revealed the presence of columnar structures only in the RNFL. Transmission electron microscopy showed that all samples contained retinal cell debris on the outer surface of the ILM. However, adhesion of retinal nerve fibers on the outer surface of the ILM was not observed in any specimen. The columnar alterations in the RNFL observed via SD-OCT resolved completely within 1 month in all eyes. At 6 months after surgery, no eyes showed scotoma on microperimetry. Further, no dissociated nerve fiber layer appearance was identified.

Vitrectomy with ILM peeling can be safely performed for ERMs with RNFL alterations, detected preoperatively by SD-OCT, without any structural or functional disturbances. The columnar alterations of the RNFL on SD-OCT may be inner retinoschisis.