Glaucoma is a condition characterized by a build-up of fluid in the eye. That extra fluid increases the pressure in the eye which in turn damages the optic nerve and leads to a slow, progressive loss of vision. When glaucoma develops, you usually don't have any early symptoms. In this way, glaucoma can steal your sight very gradually.
There are generally four types of glaucoma.
The most common form of glaucoma is called primary open-angle glaucoma. It occurs when the trabecular meshwork of the eye gradually becomes less efficient at draining fluid that circulates in the front part of the eye. Normally this fluid, called aqueous humor, maintains a healthy pressure in the eye. Much like a sink, in the normal eye, the faucet is always on and the drain is always open. In open angle glaucoma, the drain gets clogged and fluid builds up.
As this happens, your eye pressure, called intraocular pressure (IOP), rises. Raised eye pressure may lead to damage of the optic nerve. Damage to the optic nerve can occur at different eye pressures in different patients. There is not one 'right' eye pressure that is the same for everyone. Your OCB eye doctor establishes a target eye pressure for you that he or she predicts will protect your optic nerve from further damage.
Typically, open-angle glaucoma has no symptoms in its early stages and your vision remains normal. As the optic nerve becomes more damaged, blank spots begin to appear in your field of vision. You usually won't notice these blank spots in your day-to-day activities until the optic nerve is significantly damaged and these spots become large.
Low-tension or Normal-tension glaucoma
With this condition, the optic nerve shows signs of damage that are consistent with glaucoma but intraocular pressure is normal or on the low side. The diagnosis is often made after there has been some vision damage. People with low to normal-tension glaucoma are usually treated in the same way as people who have open-angle glaucoma.
This form of glaucoma is a medical emergency and unlike open-angle glaucoma, you are likely to experience symptoms (described below.) Closed angle glaucoma happens when your iris is very close to the eye's drainage angle. In this case, the iris may block the drainage angle. You can think of it like a piece of paper sliding over a sink drain. When the drainage angle gets completely blocked, eye pressure rises very quickly. People of Asian descent and those with hyperopia (farsightedness) tend to be more at risk for developing this form of glaucoma.
Call your OCB eye doctor right away should you experience the following symptoms of an acute attack:
- Your vision is suddenly blurry
- You have severe eye pain
- You have a headache
- You feel sick to your stomach (nausea)
- You throw up
Congenital glaucoma is a rare type of glaucoma that develops in infants and young children that is inherited. While far less common than the other types of glaucoma, this condition can result in blindness if not diagnosed and treated early.
Secondary glaucoma is glaucoma that results from another eye condition or disease. For example, someone who has had an eye injury, someone who is on long-term steroid therapy or someone who has a tumor may develop secondary glaucoma.
Who is at risk?