Mercy Eye Center
According to the Glaucoma Research Foundation, glaucoma affects 1 in 10 people over the age of 80 and is the leading cause of blindness in the U.S. It is often hereditary and more frequently affects older people and African-Americans over the age of 40.
Glaucoma is created when fluid is unable to naturally drain out of the eye and as a result builds up. The fluid build-up creates increased pressure in the eye which, over time, can lead to permanent optic nerve damage with partial or even total vision loss. If detected early glaucoma can usually be controlled.
There are several types of glaucoma but the two most common are primary open-angle glaucoma (POAG)
and angle-closure glaucoma
. Primary open-angle glaucoma represents nearly 90% of all glaucoma cases. It is caused by clogging in the eye drainage canals that occurs over time. Slow drainage causes the fluid pressure to build up. Open-angle glaucoma is typically symptom-free however narrow angle glaucoma usually develops rather quickly in patients. This less common form of glaucoma occurs when the angle between the corner and iris is too narrow to let fluid drain naturally so the resulting fluid build-up creates pressure inside the eye. Narrow angle glaucoma is also referred to as acute glaucoma or angle closure glaucoma.
Other types of glaucoma include:
- congenital or “childhood” glaucoma is diagnosed in infants, babies or young children; it occurs when the eye drainage canal does not develop correctly or completely during gestation and can be hereditary.
- irido corneal endothelial syndrome (ICE) is a rare form of glaucoma which develops when corneal cells spread and form adhesions between the iris and cornea. The spreading cells block the drainage tissue and damage the optic nerve. Medication and filtering surgery may be prescribed to treat ICE glaucoma.
- neovascular glaucoma is most commonly associated with uncontrolled diabetes and develops when new blood vessels grow within the eye, blocking the eye drainage canal. It is a more difficult form of glaucoma to treat.
- normal tension glaucoma is also called “normal pressure glaucoma” or “low tension glaucoma.” It occurs when the optic nerve is damaged and creates vision loss, but the pressure within the eye is within a nearly normal range.
- pigmentary glaucoma occurs when portions of pigment from the iris (the colored part of the eyeball) break off into the normal eye fluid and clog the drainage system. It can be treated by medication or surgery.
- pseudoexfoliative glaucoma is the result of material peeling off the eye lens and collecting between the cornea and iris. It can be treated by medication or surgery.
- secondary glaucoma refers to how glaucoma is caused. It is diagnosed when a medical condition such as tumor, diabetes, eye injury, inflammation, or certain prescribed drugs create increased intraocular pressure which damages the optic nerve.
Your eye doctor can diagnose glaucoma by using a variety of examination tools and processes:
- the most important tool a doctor can use to diagnose glaucoma is an ophthalmoscope, which is a tool your doctor can use to look through your pupil and directly examine your optic nerve.
- a visual field test helps your doctor determine if you have any loss of peripheral vision, which can be a sign of glaucoma. There are several processes and machines your doctor can use to test your visual field.
- a pachymeter measures the thickness of your central cornea to interpret your levels of intraocular pressure. Researchers have found that people with thin central corneas and high intraocular pressure more frequently develop glaucoma. Your eye doctor will give you numbing eye drops and then place a probe adjacent to your cornea to make the measurement.
- to examine the drainage canals and the angle of your eye where fluid normally drains, your doctor may perform a quick, harmless procedure called a gonioscopy. After administering numbing eye drops your doctor will simply hold up a small mirror to view the inside of your eye from various angles and directions.
- by using a tonometer your doctor can measure the pressure in your eye. To use a tonometer your doctor will put numbing eye drops in your eye and then sit you at a slit-lamp with your doctor on the other side. The slit-lamp allows your doctor to get a magnified view of your eye and lightly place the tonometer against your cornea to measure IOP. It is painless and takes just a few seconds.
In addition your Mercy Eye Center doctor can use several different types of the most advanced imaging tools to closely examine your eye structure, record images of your eye and then watch for any changes over time.
If you have been diagnosed with glaucoma you should have your eye pressure regularly checked until your eye doctor is confident that it is under control. In most cases your eye doctor will prescribe a treatment involving either medication or surgery, depending on the type of glaucoma you have. Medication can include eyedrops or pills; they work by either creating less fluid within the eye or helping fluid drain from the eye. If medication does not work, your eye doctor may recommend corrective surgery