Long-term Outcomes of 3+PRN Versus 5+PRN Anti-VEGF Regimens for Ischemic and Non-ischemic Central Retinal Vein Occlusion-Associated Macular Edema

• 3+PRN anti-VEGF equals 5+PRN in CRVO-ME visual and anatomic outcomes. • 3+PRN cuts injection load ≈40 % and first-year cost ≈30 % versus 5+PRN. • PRN-based, individualized therapy is clinically effective and economically sustainable for long-term CRVO-ME care. This study evaluated the long-term clinical efficacy of two pro re nata (PRN) anti–vascular endothelial growth factor (VEGF) regimens (3+PRN and 5+PRN) for managing macular edema (ME) secondary to ischemic and non-ischemic central retinal vein occlusion (CRVO). A retrospective analysis was conducted involving patients diagnosed with CRVO who were managed at the study institution between November 2014 and August 2022, with a minimum follow-up period exceeding 12 months. Changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT) were assessed at 1 month (V1), 6 months (V6), 12 months (V12), and the final observation follow-up visit (Vf). Comparisons were made the 3+PRN and 5+PRN regimens within ischemic and non-ischemic CRVO subgroups. A total of 63 eyes were included in the analysis, including 29 eyes in the 5+PRN group (15 with non-ischemic CRVO and 14 with ischemic CRVO) and 34 eyes in the 3+PRN group (19 with non-ischemic CRVO and 15 with ischemic CRVO). BCVA and CMT improved from baseline at V1, V6, V12, and Vf in both ischemic and non-ischemic cases. No statistically significant differences in BCVA or CMT were observed between the two treatment groups at any follow-up interval. The distribution of outcomes categorized as effective, moderately effective, and ineffective was also comparable between the groups. Although a higher number of injections was administered in the 5+PRN group by month 12, the total number of injections by the final visit did not differ substantially between the two groups. The 3+PRN anti-VEGF regimen demonstrated clinical outcomes comparable to those of the 5+PRN regimen in patients with CRVO-associated ME, with the benefit of requiring fewer anti-VEGF injections during the first year of treatment.