Comparison of the effectiveness of ranibizumab monotherapy vs. combined panretinal photocoagulation on the regression of neovascularization in proliferative diabetic retinopathy

Background The optimal treatment strategy for proliferative diabetic retinopathy (PDR) remains an area of active investigation. This study aimed to compare the effectiveness of ranibizumab monotherapy vs. ranibizumab combined with panretinal photocoagulation (PRP) on neovascularization regression in PDR. Methods This retrospective study analyzed 238 patients with PDR treated between January 2019 and December 2023. Patients were classified into a monotherapy group ( n = 125, ranibizumab only) and a combined PRP group ( n = 113, ranibizumab + PRP). Neovascularization regression was assessed via fundus fluorescein angiography before treatment and at 12, 24 months. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were measured before treatment and at 3, 6, 12, and 24 months. Treatment-related indicators (injection numbers, rescue therapy rates) and adverse events were recorded. Results At 24 months, the proportion of patients with residual neovascularization on the disc (NVD) was significantly lower in the combined PRP group (8.85%) than in the monotherapy group (23.20%, P = 0.003). No significant inter-group differences were found in BCVA or CRT at any time point (all P > 0.05). The combined PRP group required fewer ranibizumab injections (10.86 ± 1.72 vs. 15.23 ± 2.84, P < 0.001) and had lower rates of rescue PRP (2.65% vs. 21.60%, P < 0.001), pars plana vitrectomy (4.42% vs. 15.20%, P = 0.006), and vitreous hemorrhage (6.19% vs. 19.20%, P = 0.003). Multivariate analysis confirmed combined therapy as an independent protective factor against non-regression (OR = 0.054, P < 0.001). Conclusion For PDR, ranibizumab combined with PRP was associated with greater NVD regression, reduced treatment burden, and a lower risk of sight-threatening complications compared with ranibizumab monotherapy, while visual and anatomical outcomes were comparable between the two groups.