Effect of Duration of Silicone Oil Tamponade on Retinal Structure after Rhegmatogenous Retinal Detachment Surgery

Purpose: The aim of the study was to investigate the effect of tamponade duration on retinal changes induced by silicone oil (SO) in patients who underwent successful rhegmatogenous retinal detachment (RRD) surgery. Methods: Retrospective comparative case series of 68 patients who underwent SO tamponade for RRD. Patients were divided into 2 groups based on timing of SO removal: <6 months (group 1, n = 34) versus ≥6 months (group 2, n = 34). The main outcome measure was the change in central macular, inner, and outer retinal layer thickness (CMT, IRLT, and ORLT) before and after SO removal (SOR). Results: The median tamponade duration was 4 [Clin Ophthalmol. 2016;10:471–6, Zhonghua Yan Ke Za Zhi. 1997 Jan;33(1):39–41] months in group 1 and 8 [Arch Ophthalmol. 1994 Jun;112(6):778–85, Retina. 2004 Dec;24(6):871–7] months in group 2 (p < 0.001). The mean CMT significantly increased from 245.3 ± 22.2 μm and 238.8 ± 41.6 μm under SO to 281.3 ± 60.2 μm and 259.0 ± 43.5 μm after SOR in group 1 (p = 0.009) and in group 2 (p = 0.007), respectively. Automated segmentation measurement revealed a significant increase in mean IRLT (p = 0.014 and p = 0.013) but no change in mean ORLT (p = 0.080 and p = 0.257) in both groups. After adjustment, there was no difference between the 2 groups in terms of mean final CMT, IRLT, and ORLT and mean retinal thickness changes after SOR. There was also no correlation between the tamponade duration and macular microstructural changes or visual recovery. Conclusion: SO tamponade causes a thinning of all retinal layers, mainly affecting the inner retinal layer. However, these changes resolved following SO extraction and were not affected by longer tamponade duration.