Clinical and morphological predictors of visual outcomes following inverted internal limiting membrane flap surgery for large macular holes

PURPOSE: The purpose of the study was to evaluate the anatomical and functional outcomes of the inverted internal limiting membrane (ILM) flap technique in patients with large macular holes (MHs) and identify independent prognostic factors that predict post-operative visual acuity.
METHODS: This retrospective study included 48 eyes of 48 patients who underwent pars plana vitrectomy and inverted ILM flap technique for idiopathic MHs ≥400 μm. Pre-operative and post-operative best-corrected visual acuity (BCVA), swept-source optical coherence tomography (SS-OCT) parameters, and various clinical factors were evaluated. Multivariate regression analysis was performed to identify independent prognostic factors for the post-operative BCVA.
RESULTS: The mean BCVA improved significantly from 1.27±0.41 logMAR preoperatively to 0.62±0.37 logMAR at 6 months postoperatively (p<0.001). U-shaped closure was associated with better BCVA than V- and W-shaped closures (p=0.001). Patients with symptom duration ≤6 months and complete post-operative restoration of the external limiting membrane (ELM) and ellipsoid zone demonstrated significantly better BCVA (p<0.01). Pre-operative BCVA (β=0.637, p<0.001) and MH index (MHI) (β=−0.261, p=0.029) were significant independent determinants of post-operative BCVA.
CONCLUSION: The inverted ILM flap technique provides high anatomical closure rates and significant visual improvement in large MH surgery. Pre-operative BCVA and MHI were significant independent prognostic factors for post-operative visual outcomes. Structural SS-OCT parameters can be clinically useful in predicting post-operative functional outcomes.

Keywords: Inverted internal limiting membrane flap, Macular hole, Optical coherence tomography, Pars plana vitrectomy, Prognostic factors, Visual acuity