What is Glaucoma?
Glaucoma is the loss of sight that happens when the optic nerve is damaged. The optic nerve is damaged usually by increased ocular (eye) pressure. Pressure builds in the eye when either too much fluid is produced, or when the drainage channels are blocked. Nerve damage happens slowly, but continuously in most forms of glaucoma. This makes it difficult for you to know if you are losing your vision unless your doctor notices this. There are close to three million people in the United States with glaucoma, and most do not know that they have this condition. Without treatment, glaucoma can cause blindness. The good thing is that blindness can be prevented in 90% of glaucoma patients. The best way to prevent blindness is for a doctor is to find out that the patient has glaucoma early, and treat it before the optic nerve is damaged greatly.
Different Forms of Glaucoma
Open angle glaucomaOpen angle glaucoma is the most common form of the disease. It is caused when the cell layer, or particles thicken, and block the proper drainage of fluid from the eye.
Angle closure glaucoma
Angle closure glaucoma is usually found in people with small eyes. Unlike open angle glaucoma, closed angle glaucoma is caused by the shape of the eye, which prevents proper drainage. The iris (the colored part of the eye) blocks fluid flow from the front of the eye to the angle.
Secondary glaucoma is caused by injury to the eye, which blocks the drainage of fluid. Examples of medical conditions which may cause secondary glaucoma include: advanced cataracts, eye inflammation, or an eye tumor.
Pigmentary glaucoma is caused when flakes of pigment from the iris block the drainage of fluid. This leads to increased ocular pressure.
Pseudoexfoliation is similar to pigmentary glaucoma. It can lead to glaucoma as flakes of material build up preventing fluid drainage.
While increased ocular pressure (IOP) is the cause of all the forms of glaucoma described above, someone with high ocular pressure does not always have glaucoma. A common myth is that high ocular pressure always causes glaucoma. However, some people have what is called ocular hypertension. This is high ocular pressure that does not cause optic nerve damage.
In this form of glaucoma, also called Low-Tension glaucoma, there is normal ocular pressure. Unexpected nerve damage causes a loss of vision.
How do I Treat Glaucoma?
Most forms of glaucoma are chronic, which means that they develop slowly and last for a long time. Glaucoma can be treated with both medication and surgery. Through treatment, glaucoma cannot be cured and lost vision cannot be restored, but further vision loss can be prevented.
At this time, the best way to treat glaucoma is to lessen the intraocular pressure (IOP) which causes optic nerve damage. In order to lessen pressure in the eye, drugs decrease the volume of aqueous fluid within the eye. Miotics and epinephrine are two classes of drugs that increase the outflow of aqueous fluid, and help lessen pressure.
Beta-blockers and carbonic anhydrase inhibitors are drug classes that lessen pressure by decreasing the amount of aqueous fluid made in the eye.
Adrengic agonists lessen pressure by both decreasing how much fluid is made, and helping its outflow.
Oral medications are used only in serious cases of glaucoma because they can have serious side effects. Most cases can be controlled with eye drops.
Prosagladin analogs are a new class of drugs to treat glaucoma. They work by increasing outflow through a secondary path.
Laser surgery is another method to lessening pressure in your eye. Surgery can open the drainage channels of your eye to lessen pressure. Laser surgery works in lessening pressure immediately; however, in more than 50% of patients, the pressure increases again two years after surgery.
In what is known as conventional surgery, the surgeon creates a new channel for fluid to drain from the eye. Conventional surgery is usually done if medicine and laser surgery do not work in controlling pressure.