Efficacy of Intravitreal Bevacizumab in Neovascular Glaucoma
Efficacy of Intravitreal Bevacizumab in Neovascular Glaucoma
Purpose: To establish the efficacy and safety of intravitreal bevacizumab (Avastin) with panretinal photocoagulation (PRP) followed by Ahmed valve implantation in the treatment of neovascular glaucoma (NVG).
Method: This prospective randomized study included 40 eyes of 40 patients with refractory NVG. Twenty eyes underwent Ahmed valve implantation with intravitreal bevacizumab (Avastin) (1.25 mg in 0.5 mL) and PRP and 20 eyes were managed by Ahmed valve and PRP (control group). The follow-up period was 18 months.
Results: Complete success was defined as an intraocular pressure ≤21 mm Hg. Qualified success was considered when the above criteria were fulfilled but with additions of antiglaucoma topical medical treatment. The results revealed 95% total success (75% complete success and 20% qualified success) in the first group in which Avastin-augmented Ahmed valve was performed compared with 50% total success in the control group in which Ahmed valve implantation was performed alone (25% complete success and 25% qualified success).
Conclusions: Intravitreal bevacizumab (Avastin) with PRP followed by Ahmed valve implantation appears to be effective in the management of NVG.
Neovascular glaucoma (NVG) is a type of secondary glaucoma that arises from the formation of new vessels on the iris and in the anterior chamber angle. It is secondary to retinal and anterior segment ischemia, for example, proliferative diabetic retinopathy, central retinal vein occlusion (CRVO), etc. NVG is a potentially devastating disease; delayed diagnosis or poor management can result in complete loss of vision or, possibly, loss of the globe itself. Thus, early diagnosis followed by immediate and aggressive treatment is crucial. In managing NVG, it is essential to treat both elevated intraocular pressure (IOP) and the underlying cause of the disease. Thus, both the IOP decrease and the ocular blood flow improvement must be considered to ensure the correct amount of oxygen and nutrients to ganglion cells. There is evidence that specific inhibition of vascular endothelial growth factor can inhibit neovascularization in the iris, choroid, cornea, and retina.
Bevacizumab (Avastin, Genentech Inc.) is a monoclonal vascular endothelial growth factor inhibitor that was first used in ophthalmology to treat subretinal neovascularization in eyes with age-related macular disease. Recently, intravitreal injection of bevacizumab has been demonstrated to be a safe and successful alternative to treat retinal neovascularization in diabetic retinopathy and central or branch vein occlusions. Previous studies reported that anterior chamber neovascularization may regress after intravitreal injection of bevacizumab in eyes with NVG, with or without adjunctive laser treatment. Similar results were observed after intracameral injections. As anterior chamber inflammation and neovascular membranes may cause an increased risk of failure of filtration procedures, bevacizumab may be used as an adjunctive therapy during surgical treatment of NVG.
The application of glaucoma drainage devices with the introduction of Ahmed Glaucoma Valve (AGV) (New World Medical Inc., Rancho Cucamonga, CA) has been gaining significant momentum in the surgical armamentarium of glaucoma management in selective clinical cases. AGV implants received approval by the United States Food and Drug administration in glaucoma surgery in November 1993. During the next several years, it became the most widely used glaucoma implant worldwide. This was possibly because of the perceived advantage of its valve mechanism in limiting the occurrence of early postoperative hypotony. Tube-shunt procedures have shown encouraging results in the treatment of refractory glaucoma.There are also several different glaucoma drainage implants. These include the original Molteno implant (1966), the Baerveldt tube shunt, or the valves implants, such as the AGV implant and the later-generation pressure ridge Molteno implants. The AGV has no obstruction in its path of fluid flow. For the flow to be nonobstructive, a particle large enough to pass through the lumen of the tube will easily pass through a much larger opening of the Venturi-Flow chamber. The elastic membranes help to regulate fluid flow at all times consistently by changing their shape. The tension on these membranes is responsible for reducing hypotony.
Abstract and Introduction
Abstract
Purpose: To establish the efficacy and safety of intravitreal bevacizumab (Avastin) with panretinal photocoagulation (PRP) followed by Ahmed valve implantation in the treatment of neovascular glaucoma (NVG).
Method: This prospective randomized study included 40 eyes of 40 patients with refractory NVG. Twenty eyes underwent Ahmed valve implantation with intravitreal bevacizumab (Avastin) (1.25 mg in 0.5 mL) and PRP and 20 eyes were managed by Ahmed valve and PRP (control group). The follow-up period was 18 months.
Results: Complete success was defined as an intraocular pressure ≤21 mm Hg. Qualified success was considered when the above criteria were fulfilled but with additions of antiglaucoma topical medical treatment. The results revealed 95% total success (75% complete success and 20% qualified success) in the first group in which Avastin-augmented Ahmed valve was performed compared with 50% total success in the control group in which Ahmed valve implantation was performed alone (25% complete success and 25% qualified success).
Conclusions: Intravitreal bevacizumab (Avastin) with PRP followed by Ahmed valve implantation appears to be effective in the management of NVG.
Introduction
Neovascular glaucoma (NVG) is a type of secondary glaucoma that arises from the formation of new vessels on the iris and in the anterior chamber angle. It is secondary to retinal and anterior segment ischemia, for example, proliferative diabetic retinopathy, central retinal vein occlusion (CRVO), etc. NVG is a potentially devastating disease; delayed diagnosis or poor management can result in complete loss of vision or, possibly, loss of the globe itself. Thus, early diagnosis followed by immediate and aggressive treatment is crucial. In managing NVG, it is essential to treat both elevated intraocular pressure (IOP) and the underlying cause of the disease. Thus, both the IOP decrease and the ocular blood flow improvement must be considered to ensure the correct amount of oxygen and nutrients to ganglion cells. There is evidence that specific inhibition of vascular endothelial growth factor can inhibit neovascularization in the iris, choroid, cornea, and retina.
Bevacizumab (Avastin, Genentech Inc.) is a monoclonal vascular endothelial growth factor inhibitor that was first used in ophthalmology to treat subretinal neovascularization in eyes with age-related macular disease. Recently, intravitreal injection of bevacizumab has been demonstrated to be a safe and successful alternative to treat retinal neovascularization in diabetic retinopathy and central or branch vein occlusions. Previous studies reported that anterior chamber neovascularization may regress after intravitreal injection of bevacizumab in eyes with NVG, with or without adjunctive laser treatment. Similar results were observed after intracameral injections. As anterior chamber inflammation and neovascular membranes may cause an increased risk of failure of filtration procedures, bevacizumab may be used as an adjunctive therapy during surgical treatment of NVG.
The application of glaucoma drainage devices with the introduction of Ahmed Glaucoma Valve (AGV) (New World Medical Inc., Rancho Cucamonga, CA) has been gaining significant momentum in the surgical armamentarium of glaucoma management in selective clinical cases. AGV implants received approval by the United States Food and Drug administration in glaucoma surgery in November 1993. During the next several years, it became the most widely used glaucoma implant worldwide. This was possibly because of the perceived advantage of its valve mechanism in limiting the occurrence of early postoperative hypotony. Tube-shunt procedures have shown encouraging results in the treatment of refractory glaucoma.There are also several different glaucoma drainage implants. These include the original Molteno implant (1966), the Baerveldt tube shunt, or the valves implants, such as the AGV implant and the later-generation pressure ridge Molteno implants. The AGV has no obstruction in its path of fluid flow. For the flow to be nonobstructive, a particle large enough to pass through the lumen of the tube will easily pass through a much larger opening of the Venturi-Flow chamber. The elastic membranes help to regulate fluid flow at all times consistently by changing their shape. The tension on these membranes is responsible for reducing hypotony.
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