Methods: This prospective, single-center study included 65 eyes with RRD and cataract that underwent combined Phaco-PPV with either silicone oil or perfluoropropane (C3F8) tamponade. Patients with prior intraocular procedures, corneal pathologies, or intraoperative complications were excluded. Best-corrected visual acuity (BCVA) and specular microscopy parameters?endothelial cell density (ECD), hexagonality (HEX), and coefficient of variation (CV)?were assessed preoperatively and at 3 months postoperatively. Percentage changes in specular parameters were analyzed between the two tamponade groups.

Results: BCVA improved significantly in both tamponade groups at 3 months (p < 0.001). Both groups showed significant reductions in ECD and HEX, while CV remained stable. Percentage ECD loss was significantly greater in the C3F8 group compared to the silicone oil group (p = 0.043), whereas changes in HEX and CV did not differ significantly between tamponades. Early postoperative complications included fibrin exudation (4 eyes silicone oil vs. 11 eyes C3F8), IOP elevation (4 eyes silicone oil vs. 9 eyes C3F8), and posterior synechiae (4 eyes, C3F8 only).

Conclusions: Combined Phaco-PPV with C3F8 tamponade is associated with greater corneal endothelial cell loss compared to silicone oil, while HEX and CV remain unaffected by tamponade choice. Given the risk of future intraocular interventions, preservation of endothelial integrity is critical. Silicone oil tamponade was associated with relatively lower endothelial cell loss than C3F8 gas in patients undergoing combined phaco-PPV for rhegmatogenous retinal detachment. Keywords : Combined phaco-PPV,, rhegmatogenous retinal detachment, silicone oil, C3F8, specular microscopy