What is Neovascular Glaucoma?
Neovascular glaucoma is an aggressive form of secondary glaucoma. It is caused by abnormal blood vessel growth between the iris (colored part of the eye) and the cornea (transparent front layer of the eye).
The eye's drainage angle, located between the iris and cornea, controls the flow of aqueous humor (clear fluid of the eye). Aqueous humor gives the eye its shape and nutrients and controls intraocular pressure (IOP).
New blood vessel growth over the drainage angle disrupts the flow and drainage of eye fluid. A slight change in the filtration rate of eye fluid causes elevated intraocular pressure (IOP).
Elevated intraocular pressure can lead to optic nerve damage (the communication pathway between the eye and brain), eventually causing glaucoma.
New blood vessel growth can occur when blood flow to the eye slows down. The eye releases vascular endothelial growth factor (VEGF) proteins to compensate for low blood flow. This prompts new blood vessel growth and supplies the eye with more oxygen.
Glaucoma is an umbrella term for optic nerve damage caused by increased intraocular pressure. There is no cure for glaucoma. However, early diagnosis and treatment can help slow disease progression.
Secondary vs. Primary Glaucoma
Primary open-angle glaucoma is the most common type of glaucoma. It typically affects people over 60. It is the second leading cause of blindness worldwide. The drainage angle remains open with open-angle glaucoma, and the IOP slowly increases due to a clogged drainage system.3
Acute angle-closure glaucoma develops when the drainage angle becomes blocked, causing a sudden spike in eye pressure. Damage to the optic nerve occurs faster than open-angle glaucoma and is a medical emergency.
Depending on the new blood vessel growth location, neovascular glaucoma can be either the open-angle or acute angle-closure type of glaucoma. Neovascular glaucoma is classified as secondary because an underlying medical condition causes elevated intraocular pressure.
What Causes Neovascular Glaucoma?
Diabetes is a common cause of neovascular glaucoma.
People with diabetes are 50% more likely to develop glaucoma. Annual eye exams and maintaining healthy blood sugar levels are the best ways to prevent secondary glaucoma in people diagnosed with both type 1 and type 2 diabetes.3
Other causes of neovascular glaucoma include:
- Chronic retinal detachment
- Diabetic retinopathy (blood vessel damage in the retina)
- Central retinal vein occlusion (decreased blood flow to the eye)
- Ocular inflammatory diseases
- Systemic vascular disorders
- Ischemic retinal diseases
With diabetes, high blood sugar diminishes blood vessel integrity and causes them to leak. This decreases blood flow and damages the eye's vascular system.
Vascular endothelial growth factor (VEGF) triggers the body to create new, less effective blood vessels. These blood vessels cover or clog the drainage angle to promote healing. A clogged drainage angle decreases fluid flow rate and elevates intraocular pressure, leading to neovascular glaucoma if not treated.
What are the Symptoms of Neovascular Glaucoma?
Symptoms of neovascular glaucoma include vision loss, pain, and redness. However, the early stages of the disease are often asymptomatic.
Annual eye exams are essential for people with diabetes and for those at risk for neovascular disease.
Who is at risk of Developing Neovascular Glaucoma?
People with systemic vascular disease include are at a higher risk of developing neovascular glaucoma triggered by:
- Diabetic retinopathy
- Retinal vein blockage
- High blood pressure
- Heart disease
Controlling high blood sugar and managing heart health help prevent neovascular glaucoma.
Diagnosing & Treating Neovascular Glaucoma
An annual comprehensive eye exam is essential for people with diabetes and vascular disease.
Neovascular glaucoma is diagnosed during a comprehensive eye exam. An ophthalmologist will check for new blood vessel growth, retina damage, and changes in intraocular pressure.
Assessing optic nerve damage includes looking at the back of the eye. Vision field tests look for blind spots in peripheral vision (side vision) and visual acuity tests screen for central and distance vision changes.
The first goal of a neovascular glaucoma treatment plan is to reduce eye pressure and prevent further damage to the optic nerve. The second goal is to treat the underlying cause of retinal ischemia (decreased blood flow).
Treatment for neovascular glaucoma may include:
- Medicated eye drops to lower intraocular pressure
- Laser treatment (pan-retinal photocoagulation) reduces VEGF secretion, decreasing new blood vessel growth
- Anti-VEGF eye injections to remove new blood vessel growth
Surgical treatment is necessary when medications alone do not reduce eye pressure. Laser and traditional glaucoma surgery include:
- Tube shunt surgery, which implants a glaucoma drainage device to divert fluid into a reservoir and away from the eye
- Trabeculectomy, which creates a bleb (reservoir) to capture fluid and decrease IOP
- Cyclodestruction, a laser treatment that reduces fluid production
- Laser iridotomy, involves creating a small hole in the iris to open the drainage angle
Neovascular glaucoma is secondary glaucoma caused by new blood vessel growth between the iris and cornea. This leads to a disturbance in fluid rate and elevated intraocular pressure. Glaucoma is the result of optic nerve damage caused by high eye pressure.
New blood vessel growth occurs when the eye's tiny blood vessels are damaged (from high blood sugar or vascular disease), leading to poor blood flow. The body grows new, ineffective blood vessels that cover the drainage angle to compensate for poor blood flow.
Early glaucoma typically doesn't have many symptoms. But warning signs of neovascular glaucoma include redness, pain, and vision loss.
Treatment for neovascular glaucoma first includes lowering eye pressure and treating the underlying cause of systemic vascular disease. Medicated eye drops help decrease intraocular pressure and stop the growth of new blood vessels.
Laser treatment or traditional glaucoma surgery are used if medication alone doesn't work.
While there is no cure for glaucoma, controlling high blood sugar, lowering high blood pressure, and managing heart disease are the best ways to prevent neovascular glaucoma.
Neovascular glaucoma is diagnosed during a comprehensive eye exam. If you have diabetes or are at risk of vascular disease, getting an annual eye exam and glaucoma screening is essential.
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