As shown in RIDE (ranibizumab injection in subjects with clinically significant macular edema with center involvement secondary to diabetes mellitus) and RISE (ranibizumab injection in subjects with clinically significant macular edema with center involvement secondary to diabetes mellitus) clinical trials, 9.5% of patients required multiple PRP treatment over 24 months without additional anti-VEGF treatment [46]. This evidence concerns the gene VEGFA and macular retinal edema.