What is glaucoma?
Glaucoma is frequently called the "sneak thief of sight," because there are often no symptoms before severe vision loss occurs. This is the leading cause of blindness in the United Stated. An estimated 1 out of 50 adults are affected. Loss of sight from glaucoma is preventable with early detection and treatment by your ophthalmologist.
Glaucoma is a series of diseases of the optic nerve. The optic nerve is the nerve that carries images between the the eyes and the brain. If it becomes damaged, vision is impaired.
Glaucoma is caused by increased pressure in the eye due to a build up of a fluid, called the aqueous humor. The aqueous humor circulates through the eye, nourishing the tissues, and then exits the eye through a drainage system called the angle. The balance between fluid production and drainage creates a pressure in the eye. This pressure is independent of blood pressure. If the drainage system becomes obstructed, fluid builds up, causing the pressure inside the eye to rise. In some cases, the eye produces more aqueous humor than it can drain, which also results in a rise of pressure in the eye. This elevated pressure is rarely felt, and there are often no symptoms or side-effects until damage has already been done to the optic nerve.
Types of glaucoma
Chronic open-angle glaucoma is the most common type of glaucoma. In this type of glaucoma, the drainage angle is open, but working less efficiently, usually due to age. As a result, pressure builds up slowly, causing a gradual loss of side vision which progresses slowly and usually goes undetected until very late in the disease process.
Low Tension Glaucoma is not very common, but there are patients with normal eye pressure who have glaucoma, and sustain injury to their optic nerves.
Angle-closure glaucoma occurs when the drainage angle of the eye is totally blocked, preventing any fluid to drain. This causes the pressure inside the eye to rise suddenly. This instant rise in pressure can cause halos to appear around lights, blurred vision, headaches and severe eye pain.
Call your ophthalmologist immediately, if your are experiencing any of these symptoms. Your vision may be in danger.
Chronic angle-closure glaucoma is a more gradual and painless closing of the angle. Chronic angle-closure glaucoma occurs more frequently in people of African and Asian ancestry.
Secondary glaucoma happens when scar tissue blocks the drainage angle as a result of injury, infection or drug use. Loss of side-vision is the first symptom. Secondary glaucoma progresses much like chronic open-angle glaucoma.
Congenital glaucoma is a birth defect affecting the drainage angle. Symptoms include augmented eyes, a cloudy cornea, sensitivity to light and excessive tearing. In order to prevent blindness, this condition must be treated soon after birth.
How is glaucoma detected?
Glaucoma is most often found during a thorough eye examination. During an examination, your eye doctor will measure the intraocular pressure of your eye, inspect the drainage angle, and evaluate the structure of the optic nerve. If there is suspicion that a patient may have glaucoma, the optic nerve photos are obtained and there are other tests used to objectively evaluate the nerve. These tests include visual field testing and instrumentation that can quantify the number of optic nerve fibers
Who is at risk for glaucoma?
Anyone can get glaucoma, however some people are at a higher risk. They include:
Remember- prevention is painless, but sight loss is devastating.
- Patients over age 40
- African Americans
- People with a family history of glaucoma
- People with a history of severe anemia or shock
- People with past injuries to the eyes
- People with high refractive errors - either myopia(nearsighted) or hyperopia(farsighted)
In open angle glaucoma the primary treatment is eye drops. If drops are not successful then there are laser treatments and surgical interventions. In angle closure glaucoma the primary treatment is with a laser.
If you are diagnosed with glaucoma your ophthalmologist at Manchester Ophthalmology will review the treatments with you.