Sir,

We read with great interest the legitimate and comprehensive guidelines on retinal vein occlusions (RVO) elaborated by Sivaprasad et al.1 However, the reference data were not updated with the available long-term results of the trials, which had dealt with the efficacy of therapy with ranibizumab (Lucentis, Genentech, Inc., South San Francisco, CA, USA) and aflibercept (Eylea, Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA) for macular edema secondary to central RVO (CRVO).2, 3, 4 Specifically, the rates of unresolved macular edema were 56% in the RETAIN study,2 65.7% in the COPERNICUS study,3 and 39.4% in the GALILEO study,4 after 51.4, 24, and 18 months of follow-up, respectively. Delayed deterioration in the outcome measures in the mentioned trials could be explained by the lower frequency of injections as well as the long duration of time from CRVO diagnosis to initiation of treatment, during which time patients went without treatment for example, an average of 6.39, 2.73, and 2.6 months in the RETAIN,2 COPERNICUS,3 and GALILEO4 trials, respectively. These facts favored the delayed occurrence of ischemic and irreversible lesions of the macular ganglion cell complex, close to the foveola, with macular edema being a minor factor.

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