Intravitreal Injection for Diabetic Macular Edema as Adjunctive Therapy for Proliferative Diabetic Retinopathy: A Retrospective Study

PURPOSE: To detect the impact of intravitreal injection (IVI) therapy with sole anti-vascular-endothelial-growth-factor (VEGF) or combined with steroids treating diabetic macular edema (DME) on activity of proliferative diabetic retinopathy (PDR) based on total number of panretinal photocoagulation (PRP) spots needed within 2 years. PATIENTS AND METHODS: A retrospective study of 102 eyes with primary-onset PDR and minimum follow-up of 24 months divided into 2 groups: Group 1 (G1) 40 eyes received only PRP and did not develop DME. Group 2 (G2) 62 eyes received additional IVI-therapy due to concomitant DME, with anti-VEGF only (subgroup 2a, G2a) or in combination with steroids (subgroup 2b, G2b). Main outcomes: central macular thickness (CMT, µm), best-corrected visual acuity (BCVA, LogMAR) and total number of needed PRP spots and IVI after 24 months. RESULTS: CMT was significantly higher in G2 compared to G1, initially (p < 0.01) and after 24 months (p = 0.01). CMT was significantly higher in G2b compared to G2a, both initially (p = 0.01) and after 24 months (p < 0.01). BCVA was significantly higher in G1 compared to G2, initially and after 24 months (p = 0.01). BCVA was not significantly different between the two subgroups, initially (p = 0.54) and after 24 months (p = 0.29). The total number of PRP spots was significantly higher in G1 compared to G2 (p < 0.01) but not significantly different between the subgroups (p = 0.8). CONCLUSION: Regardless of severity of concomitant DME, IVI with sole anti-VEGF or combined with steroids reduced the total number of PRP spots needed within 2 years significantly indicating a favorable effect on activity of PDR.