Purpose: The aim is to study the changes in ocular coherence tomography (OCT) parameters of large (≥400 μ) full-thickness macular holes (FTMHs) after a failed surgery and evaluate the outcome of fluid-gas exchange (FGE) in the treatment of persistent macular hole and role of OCT in predicting outcome after the secondary intervention.
Methods: Changes occurring in the OCT parameters of FTMH after a failed vitrectomy were evaluated. FGE was done in an operating room with three pars plana sclerostomy ports. The anatomical and functional outcomes of FGE for these persistent macular holes were also assessed. Anatomical closure was defined as the flattening of the hole with resolution of subretinal cuff of fluid. Anatomical success after FGE was defined as flattening of macular hole with the resolution of subretinal cuff of fluid and neurosensory retina completely covering the fovea. Functional success was defined as an improvement of at least one line of best-corrected visual acuity (BCVA).
Results: Twenty-eight eyes (28 patients) were included in the study. After the failed vitrectomy, OCT showed an increase in the base diameter, opening diameter, and height of the hole. After the secondary procedure, anatomical closure was achieved in 89.3% eyes. Mean BCVA improved from logMAR 0.88 ± 0.24 (20/152) to logMAR 0.66 ± 0.24 (20/91) (P < 0.001). Eight (28.6%) patients achieved final BCVA ≥20/60. Functional success was obtained in 19 patients (67.9%). There was no association between anatomical success after FGE and any of the pre-FGE OCT parameters or indices.
Conclusion: Unsuccessful surgery causes swelling of the outer and middle retinal layers with retraction of inner layers of the retina. Performing FGE while visualizing the retina is a good option for the treatment of large persistent macular holes as it causes complete drying of the macula, better success rates, and a reduced complication rate. Pre-FGE OCT does not help in predicting the outcome of FGE for persistent macular hole.
Keywords: Failed surgery; fluid-gas exchange; ocular coherence tomography; persistent macular hole.