Background: In large full thickness macular holes (FTMH) the closure rate after vitrectomy and conventional internal limiting membrane (ILM) peeling is less than 90%. The aim of this study was to examine the visual acuity and anatomical success rate with high-resolution optical coherence tomography (OCT) after transconjunctival sutureless 23-gauge pars plana vitrectomy as well as intraoperative OCT (iOCT) and Brilliant Peel (BP)-assisted ILM peeling using the inverted ILM flap technique in patients with large FTMHs.
Method: In this retrospective study 25 eyes of 25 consecutive patients with large FTMH were treated by 23-G vitrectomy with BP and iOCT-assisted ILM peeling using the inverted ILM flap technique followed by gas tamponade. In all patients best corrected visual acuity (BCVA) and the maximum diameter, base and height of the FTMH as well as intraretinal alterations were measured preoperatively using high-resolution spectral domain OCT (SD-OCT, Spectralis, Heidelberg Engineering, Germany). The BCVA was measured after 1, 3, and 6 months. Additionally, the closure rate and the microstructural integrity of the outer retinal layers, e.g. external limiting membrane (ELM), ellipsoid zone und photoreceptor outer segment (OS) were registered in the SD-OCT and correlated with the results of BCVA after macular hole surgery.
Results: In all surgical procedures with the inverted ILM flap technique the application of iOCT enabled a good visualization and a controlled positioning of the ILM flaps. At baseline mean BCVA was 0.2 (0.7 logMAR) and improved significantly after 1, 3 und 6 months to 0.4 (0.4 logMAR), 0.5 (0.3 logMAR) and 0.63 (0.2 logMAR), respectively. The closure rate of the FTMHs was 100%. Microstructural integrity of the outer retinal layers was evaluated semiquantitatively and showed good correlation with BCVA.
Conclusion: Vitrectomy with BP and iOCT-assisted ILM peeling using the inverted ILM flap technique in patients with large FTMH is a very controlled and safe microsurgical strategy and shows good functional and anatomical results. The morphology of the FTMH, the ILM flap and the position of the inverted ILM flap under air was well visualized by IOCT. The microstructural integrity of the outer retinal layers is displayed in detail on SD-OCT and represents an important predictive parameter for BCVA after macular hole surgery.
Keywords: Intraoperative OCT; Inverted ILM flap; Macular hole surgery; Photoreceptor outer segment; Spectral domain OCT; Transconjunctival sutureless pars plana vitrectomy.