Treatment for Glaucoma

Glaucoma is a leading cause of visual impairment and blindness both in the United States and worldwide. It is estimated to affect 60.5 million people worldwide. Glaucoma is defined as an acquired disease of the optic nerve (neuropathy), characterized by a particular appearance of the optic nerve and by visual field defects that are usually midperipheral and in the nasal visual field. Depending upon whether the optic nerve damage is associated with an open or closed appearance to the drainage channels for aqueous humor in the front of the eye, the glaucoma is referred to as open angle (the subject of this report) or closed-angle. Mild glaucoma damage to the optic nerve may be asymptomatic, but as the damage worsens, the patient begins to have difficulty with peripheral vision, contrast sensitivity, glare, and adjusting from light to dark and dark to light - symptoms that eventually affect day to day function and quality of life. In its most severe form, glaucoma results in total, irreversible blindness. Although deficient blood supply to the optic nerve, inadequate structural support for the neurons that make up the optic nerve, and insufficient supplies of neurotrophins needed to maintain the health of the optic nerve have been hypothesized as risk factors for glaucoma, experimental models and other evidence from human participants have shown that elevated intraocular pressure (IOP) results in damage to the optic nerve in a pattern characteristic of glaucoma. Furthermore, studies have demonstrated correlations between the level of IOP and the risk of having glaucoma as well as the worsening of glaucoma once present. Other studies have demonstrated that lowering IOP reduces both the incidence of glaucoma in individuals who do not have glaucoma damage but are at high risk for its development, and the rate of progression of glaucoma in individuals with established glaucoma. Therefore, the treatments for glaucoma today all focus on the reduction of IOP, which secondarily prevents the worsening of visual field loss and may therefore prevent visual impairment and blindness. The objective of this comparative effectiveness review is to summarize the evidence regarding the safety and effectiveness of medical, laser, and other surgical treatments for open angle glaucoma (OAG) in adults. Key Questions include: KQ1. Do medical, laser, and other surgical treatments for OAG reduce visual impairment? What is the comparative effectiveness of medical treatments for reducing visual impairment, of laser and other surgical treatments for reducing visual impairment, of medical versus surgical treatment for reducing visual impairment? KQ 2. Does treatment of OAG improve patient-reported outcomes? KQ 3. Do medical, laser, and other surgical treatments for OAG lower intraocular pressure? What is the comparative effectiveness of medical treatments for lowering intraocular pressure, of laser and other surgical treatments for lowering intraocular pressure, of medical versus surgical treatment for lowering intraocular pressure? KQ 4. Do medical, laser, and other surgical treatments for OAG prevent or slow the progression of optic nerve damage and visual field loss? What is the comparative effectiveness of medical treatments for preventing or slowing the progression of optic nerve damage and visual field loss, of laser and other surgical treatments for preventing or slowing the progression of optic nerve damage and visual field loss, of medical versus surgical treatment for preventing or slowing the progression of optic nerve damage and visual field loss? KQ 5. Does lowering intraocular pressure or preventing or slowing the progression of optic nerve damage and visual field loss reduce visual impairment and change vision-related quality of life? KQ 6. What are the harms associated with medical, laser, and other surgical treatments for OAG?