Sir,

In their retrospective study Olmos et al1 compared the long-term outcomes of neovascular glaucoma (NVG) treated with and without intravitreal bevacizumab (IVB; Avastin; Genentech Inc., San Francisco, CA, USA) injections in a large-case comparison study. The authors concluded that vision and intraocular pressure (IOP) in the eyes with NVG treated with bevacizumab showed no long-term differences when compared with eyes that were not treated with bevacizumab. We would like to address some issues regarding the bevacizumab treatment in patients with central/hemicentral retinal vein occlusions (central/hemi-CRVOs)-related NVG.

The assertion made by Olson et al1 that bevacizumab only delays the need for glaucoma drainage implant surgery, serving as an effective temporizing rather than a definitive treatment, is valid only for the fully developed form of NVG (angle-closure glaucoma stage2). However, treatment with IVB injections is a very useful intervention in the early stages of NVG, that is, the prerubeotic, preglaucomatous (rubeosis iridis), and early open-angle glaucoma stages of NVG,2 for prevention or even cure of NVG3 by ablation of the ischemic drive for new vessel formation. We demonstrated, for the first time,3 that the prevention of NVG may be enhanced in patients with central/hemi-CRVOs by IVB injections administered as early as possible after the onset of occlusion. Specifically, we prospectively evaluated the cumulative prevalence of NVG in patients with acute (≤1 month after the occlusion was diagnosed) central/hemi-CRVOs treated with IVB injections.3, 4 The treatment consisted of four consecutive IVB injections given off-label in a dose of 2.5 mg per injection ~45 days apart followed by pro re nata administration over a period of 3 years. No adverse effects or ocular toxicity, including clinically evident sterile or infectious endophthalmitis, IOP increase, retinal ruptures, retinal detachment, and systemic tromboembolic events were encountered during the study. The cumulative prevalence of NVG was 4.08%, a value significantly different from that existing in patients with untreated acute CRVOs (28.5%).5

Another aspect of NVG prevention is represented by treating the patients with central/hemi-CRVOs in whom ocular neovascularization already has appeared but IOP still remains within normal limits (eg, the preglaucomatous stage of NVG2). In such cases we administer IVB injections, topical steroids, and cycloplegics; unless the neovascularization subsides with these treatments, we promptly apply panretinal photocoagulation that may prevent or delay any developing of the intractable sight-threatening NVG.

In conclusion, we believe that at a dose of 2.5 mg injected promptly before occurrence of neovascularization and IOP elevation, IVB offers a real benefit and promise for the prevention of NVG in patients with acute central/hemi-CRVOs. Early diagnosis and treatment with bevacizumab are required in order to maintain a good visual status and a satisfactory IOP control.

Author contributions

Both authors (DC and MC) were involved in design and conduct of the study; collection, management, analysis and interpretation of the data; and preparation, review or approval of the manuscript.