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Glaucoma is a group of eye diseases caused by too much pressure (called intraocular pressure, or IOP) in the eye. As the pressure increases, the optic nerve becomes damaged, which can lead to blindness. Surprisingly, it is one of the most common causes of blindness in the United States today.
Your eye has fluid in it called aqueous humor. If there is too much of the fluid or it doesn’t drain out, pressure builds up inside the eye. Glaucoma can happen in one or both eyes.
The types of glaucoma depend on the cause of the pressure. There is open-angle glaucoma, which is the most common type, and closed-angle glaucoma. There are other types of glaucoma as well, such as normal-tension glaucoma, caused by damage to the optic nerve without pressure, and developmental glaucoma, which affects young children; however, open- and closed-angle glaucoma are the most common ones.
With open-angle glaucoma, the pressure builds up slowly because the fluid is not draining as well as it should. With closed-angle glaucoma, the fluid becomes blocked and the pressure builds up very suddenly.
There are several risk factors for glaucoma:
- Having a high intraocular pressure
- Being older than 60 years (40 if you are African American)
- Being African American or Asian
- Having family members who have glaucoma
- Having certain medical conditions, such as diabetes, heart disease, or hypothyroidism
- Having other eye problems, such as detached retina, or eye injuries
- Using corticosteroid medications, especially in eye drop form.
Symptoms of glaucoma depend on the type you have. Open-angle glaucoma can happen very slowly without any noticeable signs at first. Many people only find out they have glaucoma when they get their eyes checked. Signs and symptoms include:
- Gradual loss of peripheral (side) vision
- Tunnel vision
Acute closed-angle glaucoma signs come on suddenly and can cause:
- Pain in the eye, can be severe
- Changes in your vision, especially in dim light
- Blurriness, halos around lights
- Red eyes
- Nausea and vomiting
Optometrists and ophthalmologists can check for glaucoma using a few different tests:
- Tonometry – The doctor uses a puff of air or touches the eye with a tiny device (after giving numbing eye drops) to measure internal pressure.
- Ophthalmoscopy – After dilating your pupils with special drops, the eye doctor looks directly into your eye to look for damage and to examine the optic nerve.
- Perimetry – This is also called the visual field test. Your peripheral or side vision is checked by having you follow a beam of light from side to side.
- Pachymetry – After your eye is numbed with drops, the doctor measure the thickness of your cornea, using a small probe.
Glaucoma can’t be cured, but open-angle glaucoma can be managed, slowing down the pressure build up so it doesn’t cause as much damage. This is done with:
- Oral medication (pills)
- Laser surgery
- Trabeculectomy, surgery that removes a bit of eye tissue to make an opening for the fluid to drain
- Drainage implant, a small tube that makes a drainage path for the fluid
If you have any symptoms of closed-angle glaucoma, this is a medical emergency and you must get medical help as quickly as possible to prevent permanent eye damage. Doctors often use laser surgery immediately, and then work on what may have caused the glaucoma in the first place. This is to prevent the pressure from building up again.
If you have glaucoma, there are some precautions you must take to reduce the risk of the pressure building up too high. This includes always taking your medications as prescribed, including the eye drops. Also, tell any doctor or nurse practitioner who may prescribe medications that you have glaucoma. Some medications can increase the pressure. If you want to take an over-the-counter medication or a supplement, ask your pharmacist if the product is safe for you to take. And finally, try not to put extra pressure on your eyes by rubbing them too hard.