Neovascular glaucoma (NVG) is a painful and potentially blinding secondary glaucoma. It is associated with a reduction of the blood supply to the retina due to blood vessel blockage. To compensate for the lack of blood flow, the retina releases vascular endothelial growth factors (VEGFs) to stimulate the formation of new abnormal blood vessels. Thus, treatment of the underlying cause of NVG is as important as reducing intraocular pressure (IOP) and inflammation associated with NVG.
The conventional treatment for NVG is panretinal photocoagulation (PRP), wherein a laser is used to destroy areas of the retina in order to minimize the blood supply needed by the retina, and thus reduce growth of new abnormal blood vessels. However, poor view of the retina in the back of the eye may prevent its use. Anti-VEGF agents, which are injected into the eye, may prevent the growth of abnormal blood vessels. Another potential advantage of anti-VEGF agents over PRP is the reduced time needed to recover from the procedure because of ocular inflammation and/or blurred vision associated with PRP. The effects of anti-VEGF agents for treating NVG, however, may be temporary, generally lasting four to six weeks.
Although we identified many published reports on anti-VEGF agents in NVG, none were eligible for inclusion. More research is needed to investigate the effect of these agents compared with or in addition to conventional surgical or medical treatment in lowering IOP in NVG.
Currently available evidence is insufficient to evaluate the effectiveness of anti-VEGF treatments, such as intravitreal ranibizumab or bevacizumab, as an adjunct to conventional treatment in lowering IOP in NVG. Well designed RCTs are needed to address this issue, particularly trials that evaluate long-term (at least six months) benefits and risks since the effects of anti-VEGF agents may be short-term only. An RCT comparing anti-VEGF agents with no anti-VEGF agents taking into account the need for co-interventions, such as panretinal photocoagulation (PRP), glaucoma shunt procedures, cyclodestructive procedures, cataract surgery, and deep vitrectomy, could be of use to investigate the additional beneficial effect of anti-VEGF agents in treating NVG. Since decisions for when and which co-interventions should be used are based on clinical criteria, they would not be appropriate for randomization. However, the design of a study on this topic should aim to balance groups by stratification of co-intervention at time of randomization or by enrolling a sufficient number of participants to conduct subgroup analysis by co-interventions (ideally 15 participants per treatment group for each subgroup). Alternatively, the inclusion criteria for a trial could limit participants to those who receive the same co-intervention.
Neovascular glaucoma (NVG) is a potentially blinding secondary glaucoma. It is caused by the formation of abnormal new blood vessels which prevent normal drainage of aqueous from the anterior segment of the eye. Anti-vascular endothelial growth factor (anti-VEGF) agents are specific inhibitors of the primary mediators of neovascularization. Studies have reported the effectiveness of anti-VEGFs for the control of intraocular pressure (IOP) in NVG.
To compare the IOP lowering effects of intraocular anti-VEGF agents to no anti-VEGF treatment, as an adjunct to existing modalities for the treatment of NVG.
We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to January 2013), EMBASE (January 1980 to January 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov/) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 11 January 2013.
We included randomized controlled trials (RCTs) and quasi-RCTs of people treated with anti-VEGF agents for NVG.
Two authors independently assessed the search results for trials to be included in the review. Discrepancies were resolved by discussion with a third author. Since no trial met our inclusion criteria, no assessment of risk of bias or meta-analysis was undertaken.
No RCTs were found that met the inclusion criteria for this review. Two RCTs of anti-VEGF agents for treating NVG were not included in the review due to the heterogeneity and uncontrolled assignment of adjunct treatments received by the study participants.