Sir,

The article by Nghiem-Buffet et al1 evaluated ophthalmology and treatment visits for ranibizumab (Lucentis; Genentech, Inc., South San Francisco, CA, USA) and dexamethasone (Ozurdex; Allergan, Irvine, CA, USA) in treating naive patients with macular oedema (MO) secondary to retinal vein occlusion in the routine clinical practice in the USA using US patient-level medical claims data.

We would like to address the great discrepancy compared to the current standards regarding the number of treatment visits with ranibizumab and dexamethasone in patients with MO resulting from central retinal vein occlusion (CRVO). A number of 4.1 ranibizumab injections and 1.8 dexamethasone implant injections within a period of 12 months represents approximately half of the standard claimed by the pivotal studies and the current recommendations, and indicates that patients have been insufficiently treated. Thus, the standard injection scheme during the first year of intravitreal ranibizumab therapy for MO owing to CRVO was clearly set by the level 1 evidence of the Cruise study,2 that is, ranibizumab should be given monthly for the first 6 months, with a subsequent 6-months dosing, as required. The current valid recommendations3 consider that the duration of ≥3-line improvement after dexamethasone implant is typically 2–3 months and that the reinjections generally will be performed after 4–5 months. Similarly, the study by Callanan et al4 demonstrated that treatment with dexamethasone implant every 5 months improved the final outcomes in patients with diabetic MO and met the a priori criteria for noninferiority to ranibizumab in average change from baseline visual acuity over 12 months. Noninferiority was achieved with an average of 2.85 dexamethasone implant injections and 8.70 ranibizumab injections.

Altogether, regardless of the intravitreal pharmacotherapy chosen, for example, specific (ranibizumab) or nonspecific (dexamethasone implant) anti-vascular endothelial growth factor (VEGF) agents, the efficacy of treatment depends primarily on the precociousness of the therapy after CRVO onset. Therefore, therapy with anti-angiogenic agents has to be promptly applied as soon as possible after the CRVO onset. Every delay of therapy adversely influences the deterioration of visual functions, which is difficult to restore even with subsequent treatment.5 Both groups of anti-VEGF substances provide similar rates of vision improvement but with superior anatomic outcomes and fewer injections in the dexamethasone implant-treated eyes. However, more patients receiving the dexamethasone implant lose vision mainly due to cataract.