Evaluating inner retinal dimples after inner limiting membrane removal using multimodal imaging of optical coherence tomography

BACKGROUND: To evaluate inner retinal dimples after peeling of the inner limiting membrane (ILM) for macular holes (lamellar macular hole [LMH] and full-thickness macular hole [FTMH]) via multiple imaging modes of spectral-domain optical coherence tomography (OCT) and to assess their relationship with preoperative vitreoretinal interface conditions. METHODS: The data of 38 eyes in 35 patients who underwent surgery for LMH, and FTMH were retrospectively studied. The presence of postoperative inner retinal dimples was judged by a combination of en face OCT layer images and cross-sectional images. The demographic and clinical characteristics of eyes with and without inner retinal defects were compared to identify factors involved in the formation of the defects. RESULTS: Inner retinal defects were found in 26 eyes (68%) after surgery. They appeared on the en face OCT ILM layer images as multiple dark spots limited to the ILM peeling area, and corresponded to dimples or pitting of inner retinal layers on cross-sectional OCT images. In 5 cases (19%), apparent progression of inner retinal defects was observed on the en face OCT images as increasing numbers and sizes of the dark spots, which seemed to follow an eccentric growth pattern starting from the central macula. In addition, highly myopic eyes were found to be associated with the formation of more severe inner retinal defects. CONCLUSIONS: Multiple imaging modes of en face spectral-domain OCT provide comprehensive information about the appearance of inner retinal dimples. High myopic eyes seem to develop more severe inner retinal defects after ILM peeling.