Glaucoma is a term used to describe a number of diseases of the human eye, all of which have different causes and treatments. Unfortunately, the onset of glaucoma rarely has any warning signs. Yet it is estimated that 4 million Americans have glaucoma and 14 million people worldwide have glaucoma. At least half these people are unaware they have glaucoma. In fact, untreated glaucoma is a leading cause of irreversible blindness.
Essentially, glaucoma is a collection of problems that lead to elevated pressure within the eye, which is called intraocular pressure. An increase in the intraocular pressure(s) can damage the optic nerve (the nerve that allows you to see) and seriously affect your vision. Its onset is usually gradual and can take many years before it begins to affect your vision. Typically, a loss of peripheral (side) vision is among the first signs of glaucoma, but even this can be so subtle it may go unnoticed.
The most common form of glaucoma is called primary open-angle glaucoma and it can develop undetected for years. Glaucoma can cause irreversible loss of vision and severe damage to the nerve fibres that pass through the optic nerve in the back of the eye.
Acute closed-angle glaucoma is caused by a rapid rise in the eye pressure, which causes acute pain in the eyes. This condition tends to appear suddenly and is considered an ophthalmic emergency requiring immediate treatment.
Normotensive or low tension glaucoma occurs when the eye pressure is normal (21 millimeters of mercury or less). Nevertheless, progressive optic disc and visual field changes similar to those seen in people with primary open-angle glaucoma do occur.
To date, there is no cure for glaucoma. Therefore, the early detection and treatment of glaucoma is key in both treating the disease and preventing blindness.
Some guidelines recommend that you be tested for glaucoma by an ophthalmologist or optometrist:
- before age 40: every 2 to 4 years
- age 40 to 54: every 1 to 3 years
- age 55 to 64: every 1 to 2 years
- after age 65: every 6 to 12 months
You should ask your ophthalmologist or optometrist what they recommend for you.
Frederick S. Mikelberg, MD
in association with the MediResource Clinical Team