Glaucoma is the leading cause of blindness and visual impairment in the US. It can affect patients of all ages, many of who do not experience any symptoms and may not be aware that they have the disease. Many patients do not experience any symptoms during the early stages of glaucoma, including no pain and no vision loss. This makes it difficult for many patients to know if they have the disease. But as glaucoma progresses, patients may experience:
a loss of peripheral or side vision
sudden intense eye pain
Glaucoma is a disease of the optic nerve, which transmits the images you see from the eye to the brain. The optic nerve is made up of many nerve fibers (like a fiber optic cable). Glaucoma damages the nerve fibers, which can cause blind spots and vision loss. Glaucoma has to do with the pressure inside of the eye, called intraocular pressure (IOP). There are two main types of glaucoma:
Open-angle, or primary glaucoma is the most common type of glaucoma and involves the aqueous fluid in the eye not draining properly through the trabecular meshwork, or the drainage canal of the eye. This can cause elevated eye pressure. When ocular pressure is above normal, the risk of developing glaucoma increases. Ocular hypertension is often a forerunner to open-angle glaucoma. Most people who develop this type of glaucoma have no symptoms until their vision is impaired.
Angle-closure glaucoma is a sudden attack of glaucoma and is considered a true eye emergency. In acute angle-closure glaucoma, the iris (colored part of the eye) can completely close off the drainage canal of the eye, causing a build-up of aqueous fluid. This fluid has nowhere to drain and causes a sudden and high increase in intraocular pressure, which leads to optic nerve damage and vision loss within hours. Symptoms include nausea, vomiting, seeing halos around lights and eye pain.
While some patients may experience symptoms from glaucoma as the disease progresses, others do not learn they have the condition until they undergo a routine eye exam. Tests performed to diagnose glaucoma include:
visual acuity test to check central vision
visual field test to check peripheral vision
tonometry to measure the pressure inside the eye
pachymetry to measure the thickness of the cornea
gonioscopy to inspect the eye’s drainage angle
ophthalmoscopy to view the fundus and optic nerve
optical coherence tomography to scan for optic nerve changes associated with glaucomatous damage
Once glaucoma has been diagnosed, treatment should begin as soon as possible to help minimize the risk of permanent vision loss. There is no cure for glaucoma, so treatment focuses on relieving symptoms and preventing further damage from occurring. Treatments include:
Eye drops to reduce fluid production in the front of the eye or to help drain excess fluid
Laser surgery to increase the outflow of fluid from the eye or eliminate fluid blockages. Laser surgery is done in the office and includes:
LPI – Laser peripheral iridotomy
LPI is the treatment for angle-closure glaucoma in which a small hole is made in the iris using a laser. The hole allows fluid build-up from behind the eye to drain into the front of the eye and out the drainage canal, thus reducing intraocular pressure and pressure on the optic nerve. This also allows the iris to return to its normal position, thus eliminating the risk of angle-closure.
SLT – Selective laser trabeculoplasty
SLT is a laser surgical procedure to help lower intraocular pressure in patients with open-angle glaucoma. SLT treats the eye’s drainage canal, or the trabecular meshwork, to help improve the flow of fluid out of the eye, thus helping to lower the pressure.
Outpatient Surgery - When medications and laser surgeries do not lower your eye pressure adequately, microsurgery may be recommended. Microsurgery creates a new channel to drain fluid from the eye and reduces the pressure that causes glaucoma. There are several surgical options available including:
Trabeculectomy involves creating a new drainage hole into the sclera (white part of the eye) to allow the fluid to flow out of the eye into a filtering area called a bleb. This reduces intraocular pressure within the eye. This filtering bleb is mostly hidden under the eyelid. The EX-PRESS® mini shunt involves placing a thin, flexible tube with a silicone pouch in the eye to facilitate drainage in order to lower the eye’s intraocular pressure. This device can be used in combination with trabeculectomy surgery.
iStent® is one of the smallest medical devices approved by the FDA. It is a new approach to glaucoma treatment called MIGS (minimally invasive glaucoma surgery). It is a micro-bypass system or stent that creates a permanent opening in the drainage canal of the eye (trabecular meshwork), working continuously to reduce the eye pressure. It is done at the time of cataract surgery in individuals with open-angle glaucoma.
Shunt procedures involve the placing of a drainage tube in the eye to create a new channel for fluid to flow from the eye into a filtering area, called a bleb. A tiny plate placed on the eye helps the bleb form and remain open. The tube is covered with a patch and is typically not seen or felt.
Most cases of glaucoma can be treated with eye drops, laser surgery or microsurgery. The best treatment for your individual case depends on the type and severity of the disease, and can be discussed with your doctor.
While there are no surefire ways to prevent glaucoma from developing, regular screenings and early detection are the best forms of protection. Some people are at a higher risk for developing disease. These people may include those who:
Are over the age of 60
African Americans over the age of 40
Have a family history of glaucoma
Have poor vision
Patients should have a comprehensive dilated eye exam at least once every two years, especially if they have a higher risk of developing glaucoma. Older patients may be encouraged to be tested more frequently.