Purpose:

To investigate the inner retinal layer outcome after internal limiting membrane (ILM) peeling in idiopathic epiretinal macular membrane (ERM) with new Spectral Domain Optical Coherence Tomography (SD-OCT).

Design:

Prospective, randomized, comparative case series Participants: Thirty-four eyes with ERM underwent pars plana vitrectomy with (n= 19) or without (n= 15) ILM peeling associated.

Methods:

Vitrectomy and ERM removal were performed using brilliant peel staining before and after ILM peeling. All eyes were examined pre- and postoperatively (W1, M1, M3, M6) using Spectralis HRA (Heidelberg) with autofluorescence, red free, infrared filters and SD-OCT with B-scan and C-scan images. Videos of the surgeries are retrospectively analyzed.

Results:

In the ILM peeled group a dissociated optic nerve fiber layer (DONFL) appearance was detected in 12 eyes (63%) on Red free filters. Dimples of the nerve fiber layer are seen in 19 eyes (100%) which correspond to the DONFL appearance. It appears at M1 visit and persists until M6 and was never seen in the non-ILM peeled group. C-scan or en face OCT shows a dimpling of the inner retinal layer which correspond to the area of the ILM peeling. Swelling of the arcuate nerve fiber layer (SANFL) was detected in 14 eyes (73%) in the ILM peeled group and in 5 eyes (33%) in the non ILM peeled group. It appears at W1 and regress at M1 visit. Autofluorescence imaging shows a dark point at the beginning of the arcuate striae and correspond to the initiated peeling with the forceps on the video.

Conclusion:

SD-OCT is more sensitive than Red free photography to detect DONFL appearance which correspond actually to dimples in the inner retina. New en face OCT is very useful in this indication. Autofluorescence and infrared photography show transient SANFL which probably correspond to a direct traumatism when peeling. Thus, peeling in the temporal inferior area may be the best way to begin the surgery and avoid microscotoma. Multimodal examination (HRA and SD-OCT) allows us to describe two different ways of healing after ILM removal. ILM peeling is correlated with SANFL and DONFL and further functional studies are necessary to analyze such nerve fiber layer defects.