Glaucoma is a group of diseases of the optic nerve involving loss of retinal ganglion cells in a characteristic pattern of optic neuropathy. Although raised intraocular pressure is a significant risk factor for developing glaucoma, there is no set threshold for intraocular pressure that causes glaucoma. One person may develop nerve damage at a relatively low pressure, while another person may have high eye pressure for years and yet never develop damage. Untreated glaucoma leads to permanent damage of the optic nerve and resultant visual field loss, which can progress to blindness.

Fortunately, medical advances have made it easier to diagnose and treat glaucoma. If detected and treated early, glaucoma need not cause even moderate vision loss. But having glaucoma does mean regular monitoring and treatment for the rest of your life.

What causes glaucoma?

The eye constantly produces aqueous, the clear fluid that fills the anterior chamber (the space between the cornea and iris). The aqueous filters out of the anterior chamber through a complex drainage system. The delicate balance between the production and drainage of aqueous determines the eye’s intraocular pressure (IOP). Most people’s IOPs fall between 8 and 21. However, some eyes can tolerate higher pressures than others. That’s why it may be normal for one person to have a higher pressure than another.

Glaucoma Symptoms

Glaucoma is often referred to as the "silent thief of sight," because most types typically cause no pain and produce no symptoms. For this reason, glaucoma often progresses undetected until the optic nerve already has been irreversibly damaged, with varying degrees of permanent vision loss.

But with acute, angle-closure glaucoma, symptoms that occur suddenly can include blurry vision, halos around lights, intense eye pain, nausea, and vomiting.

HOW IS GLAUCOMA DETECTED?

Regular eye examinations are the best way to detect glaucoma early.

A glaucoma test usually includes the following:

* optic nerve check with an ophthalmoscope

* eye pressure check (tonometry)

* visual field assessment if needed - this tests the sensitivity of the side vision, where glaucoma strikes first

Does increased eye pressure mean that I have glaucoma?

Not necessarily. Increased eye pressure means you are at risk for glaucoma, but does not mean you have the disease. A person has glaucoma only if the optic nerve is damaged. If you have increased eye pressure but no damage to the optic nerve, you do not have glaucoma. However, you are at risk. Follow the advice of your eye care professional.

Treatment

Yes. Immediate treatment for early stage, open-angle glaucoma can delay progression of the disease. That's why early diagnosis is very important. Although open-angle glaucoma cannot be cured, it can usually be controlled. While treatments may save remaining vision, they do not improve sight already lost from glaucoma.

Prevention

There is no way to prevent open angle glaucoma, but vision loss from open angle glaucoma can be prevented. Early diagnosis and careful management of the condition, if diagnosed, are the keys to preventing vision loss.

Most people with open angle glaucoma have no symptoms. All persons over 40 should have an eye examination at least every 5 years, and more often if in a high-risk group. Those in high-risk groups include people with a family history of open angle glaucoma and people of African heritage.

The most common treatments for glaucoma are medication and surgery.