Bidirectional Dimples After Internal Limiting Membrane Peeling for a Macular Hole

PURPOSE: To investigate microstructural changes and prognosis associated with retinal surface dimples after internal limiting membrane (ILM) peeling for macular holes (MHs). METHODS: We analyzed swept-source optical coherence tomography (SS-OCT) images of patients who underwent surgery for idiopathic MHs. The inner retinal dimples on SS-OCT images were classified into three types: unidirectional, bidirectional, and complicated bidirectional dimples. RESULTS: Dimples were found in 97.1% of the 69 eyes (69 patients) during a mean follow-up period of 14.0 ± 11.9 months after MH surgery. Of the eyes with dimples, 83.6% had bidirectional dimples. The proportion of eyes with dimples increased from 55.3% at 1 month postsurgery to 95.5% at 3 months and 97.9% at 6 months postsurgery. However, the proportion of eyes with complicated bidirectional dimples gradually increased from 1 month (29.8%) to 3 months (46.3%) and 6 months (64.6%) postsurgery. In the multivariable generalized estimating equation model, complicated bidirectional dimples occurred more frequently in eyes with shorter axial length (P = 0.039) and longer follow-up duration (≥6 months; at 6 months: P = 0.001; at 12 months: P = 0.009). CONCLUSIONS: Changes in retinal layers associated with retinal surface dimples after ILM peeling can occur at different retinal depths and over different time courses. These findings suggest the progression of dimple-associated remodeling of the underlying retinal layer. TRANSLATIONAL RELEVANCE: Various types of dimples can be used as surrogates to evaluate structural changes and outcomes of MH surgery.