Silicone oil-associated visual loss in macula-on rhegmatogenous retinal detachment – does the tamponade duration affect the outcome?

BACKGROUND: Silicone oil (SO)-associated unexplained visual loss (UVL) is a serious phenomenon after pars-plana-vitrectomy (ppV). Due to reports of UVL, we started earlier SO removal (SOR) in macula-on rhegmatogenous retinal detachments (RRD) in 2020. This study aims to investigate the effect of a shorter (≤ 60 days) compared to a long-term (> 60 days) SO tamponade. METHODS: All consecutive macula-on RRDs (2020-2025) treated with ppV were retrospectively analysed comparing eyes with short-term vs. long-term SO tamponade regarding best corrected visual acuity (BCVA), intraocular pressure (IOP), central foveal thickness (CFT) and the incidence of UVL. Inclusion criteria were a detailed clinical documentation and a minimum follow-up (FU) of 2 months after SOR. If available, CFT values were analysed before, during, and after SO. RESULTS: Overall, 37 eyes received ppV with SO for macula-on RRD. In 25 eyes (68%), SOR was performed within 60 days. Due to organizational issues (Covid, capacity) or patient-related factors (cancellation, illness), SO remained for longer than 60 days in 12 eyes (32%). Primary reattachment was achieved in all eyes. In the short-term group SOR was after 36 days (SD 13.4) and in the long-term cohort after 92 days (SD 20.9). UVL (≥ 2 Snellen lines BCVA loss without correlate) was significantly more common in the long-term (5/12) than in the short-term SO group (0/25) (p = 0,002). There were no differences in intra -and postoperative parameters (cut-suture time, IOP, CFT). Eyes with long-term SO had a final BCVA of logMAR 0.5 (SD 0.34) compared to a preoperative BCVA of logMAR 0.3 (SD 0.21). In eyes with short-term SO the BCVA before surgery (0.3; SD 0.29) and after SOR (0.3; SD 0.28) were comparable. The final BCVA after SOR was significantly better after short-term than after long-term tamponade (p = 0.033). CONCLUSION: Eyes with a shorter SO tamponade (≤ 60 days) had better postoperative BCVA, while 42% in the long-term group (> 60 days) experienced UVL Taking into account the limitations of our small cohort, the risk of UVL during SO tamponade should be considered, especially in macula-on cases. Currently, an early SOR is the only modifiable surgical approach to address this adverse event. TRIAL REGISTRATION: The study was approved by the local ethics committee on 31st of October 2025 (Ethikkommission der Universität Regensburg, Votum 254385104) and was conducted in accordance with the ethical standards of the Declaration of Helsinki.