Evaluation of retinal vascular structures using optical coherence tomography angiography before and after silicone oil removal in eyes undergoing pars plana vitrectomy with silicone oil injection for rhegmatogenous retinal detachment

Abstract Introduction: Silicone oil has a toxic effect on retinal vascular structures. Following silicone oil removal, this toxic effect may resolve, leading to improvements in retinal parameters. The aim of this study was to compare retinal vascular structures using optical coherence tomography angiography (OCTA) before and after silicone oil removal, and to evaluate the correlation of changes in these parameters with best-corrected visual acuity (BCVA) and intraocular silicone oil retention time. Materials and Methods: Twenty-eight patients who underwent pars plana vitrectomy (PPV) and silicone oil injection for rhegmatogenous retinal detachment were included. OCTA measurements were performed and recorded at the first week before silicone oil removal and at the 10th day, 1st, 3rd, and 5th months after removal. Results: Of the 28 patients, 8 were female and 20 were male, with a mean age of 56.39 ± 9.70 (range, 40–73) years. The mean intraocular silicone oil retention time was 6.35 ± 3.38 (range, 2–13) months. Following silicone oil removal, an increase in parafoveal inner retinal thickness and radial peripapillary capillary intra-disk density values was observed. BCVA improved. RSLT thickness decreased while the vertical C/D ratio increased. There was a positive correlation between BCVA and optic disk vascular density parameters. Silicone oil retention time did not show a correlation with any parameters. Conclusion: PPV and silicone oil injection cause permanent vascular insufficiency in both superficial and deep capillary plexuses, independent of silicone oil retention time. After silicone oil removal, radial peripapillary capillary intra-disk density values and BCVA increase. There is still no consensus regarding the optimal timing for silicone oil removal; however, we believe this period should be shorter than four months.