Investigation of changes in inner retinal layers and peripapillary nerve fiber layer in cases undergoing pars plana vitrectomy with silicone oil endotamponade for rhegmatogenous retinal detachment

Purpose: The aim of this study was to evaluate changes in retinal layer thickness measured by optical coherence tomography (OCT) in eyes treated with pars plana vitrectomy (PPV) and silicone oil tamponade for rhegmatogenous retinal detachment (RRD), and to investigate the relationship between these changes and visual prognosis. In addition, postoperative intraocular pressure (IOP) and peripapillary retinal nerve fiber layer (pRNFL) alterations were also examined. Materials and Methods: This retrospective study included data from 26 eyes of 26 patients who underwent PPV with silicone oil tamponade for the treatment of RRD. Preoperative and postoperative best-corrected visual acuity (BCVA) and OCT findings were analyzed. Measurements were taken at postoperative 1 month, 3 months, and 1 month after silicone oil removal. Postoperative changes in peripapillary RNFL, macular RNFL (mRNFL), central macular thickness (CMT), ganglion cell layer (GCL), inner nuclear layer (INL), outer nuclear layer (ONL), inner plexiform layer (IPL), outer plexiform layer (OPL), ganglion cell–inner plexiform complex (GC-IPL), and ganglion cell complex (GCC) were compared with a healthy control group. Results: The mean age of the patients was 59.03±9.53 years, and 20 (76.9%) were male. The mean BCVA was 0.03±0.04 preoperatively and improved to 0.10±0.08 at postoperative month 1, 0.21±0.15 at month 3, and 0.32±0.18 at one month after silicone oil removal (Snellen, p<0.001). Significant thinning was observed in the superotemporal, superonasal, and inferonasal segments of the pRNFL at postoperative month 1. Although a noticeable increase was detected in mRNFL thickness, significant thinning of the GCL, GC-IPL, and GCC was observed postoperatively, especially in the superior, inferior, and temporal sectors. Widespread and statistically significant thinning of the ONL was also noted, particularly in the superior, nasal, and inferior segments. Conclusion: This study enabled detailed mapping of time-dependent changes in inner retinal layers in eyes that underwent PPV and silicone oil tamponade for RRD and identified key structural parameters requiring postoperative monitoring. The findings highlight damage predominantly affecting the ganglion cell layer, inner plexiform layer, outer nuclear layer, and pRNFL. These results suggest that both the potential toxic and mechanical effects of silicone oil should be considered and that regional layer-specific OCT analysis is crucial for postoperative retinal follow-up.