In their excellent study (the GALILEO trial), Ogura and associates prospectively evaluated the efficacy and safety of intravitreal aflibercept (IVA; VEGF Trap-Eye: Regeneron Pharmaceuticals, Inc, Tarrytown, New York, USA and Bayer Healthcare Pharmaceuticals, Berlin, Germany) injections in patients with macular edema secondary to central retinal vein occlusion (CRVO). At week 76, 57.3% of the patients gained ≥15 Early Treatment Diabetic Retinopathy Study (ETDRS) letters at their best-corrected visual acuity (BCVA); the mean change from baseline BCVA was 13.7 ETDRS letters, and the mean change from baseline central retinal thickness (CRT) was −389.4 μm. Our recent prospective study dealing with intravitreal bevacizumab (IVB; Avastin; Genentech, Inc, San Francisco, California, USA) injections in patients with acute central/hemicentral retinal vein occlusions yielded similar results. At week 144, 64.9% of the patients had gained ≥15 ETDRS letters; the mean change from baseline BCVA was 19.6 ETDRS letters, and the mean change from baseline CRT was −317.18 μm. However, there are major differences between the 2 studies that can be summarized as follows.
Of the patients included in the GALILEO study, 86.4% had a perfused retinal status. In addition, the proportion of patients with posterior nonperfusion was very low (6.8%), whereas such patients represented 50% of the cases in our study.
CRVO patients were included in the GALILEO study if their occlusive event was diagnosed within 9 months before initiation of the treatment (a mean of 78 days without treatment). Our cases were diagnosed within 1 month of CRVO onset (a mean of 17.94 days).
In the GALILEO study 8 patients (7.8%) progressed to neovascularization (NV); in 2 of the patients, panretinal photocoagulation was performed. In our study, there were 2 mild cases of NV (3.5%), both of which were rapidly reversed after IVB injections.
The most common serious adverse ocular event reported by the GALILEO study was worsening of macular edema (39.4%) from baseline to week 76. We believe that the chronic and progressive development of macular edema, as well as the decreased improvements until the end of the follow-up at week 24 (mean loss of 2.9% in patients who gained ≥15 ETDRS letters; mean loss of 4.3 ETDRS letters; mean increase of 59.2 μm in CRT ), were signs of disease progression in treated patients. Most likely, there were persistent cystic changes within the neurosensory retina. The primary cause of visual deterioration was ischemic irreversible lesions of the macular retinal ganglion cells, close to the foveola. The changes were favored by the long period of time before the initiation of therapy, during which patients went without treatment (mean of 78 days). At the end of the follow-up period in our series, there were 5 cases with macular edema caused by subretinal fluid that resolved after IVB injections, with rapid restoration of macular morphology.
In conclusion, regardless of the anti-VEGF agents used, the efficacy of therapy depends primarily on the precociousness of the treatment after CRVO diagnosis.