Glaucoma, a disease of the optic nerve that, left untreated, can cause blindness, occurs in approximately 1 percent to 2 percent of the population over the age of 40, says Dr. Donald Abrams, chief of Sinai Hospital's Department of Ophthalmology based at the Krieger Eye Institute. However, in some populations, such as among African-Americans, the disease occurs more frequently; and in some age groups, it can occur in 6 percent to 10 percent of the population.
But the disease often goes undiscovered - and untreated. Some doctors estimate that as many as 50 percent of glaucoma cases go undiagnosed, Abrams says.
What is glaucoma?
It is a disease of the optic nerve in which the nerve degenerates because, in most cases, the pressure in the eye is too high. In most cases, the patient's own drainage system can't handle the fluid the eye is making on the inside, so the pressure builds up. We don't really have a good answer as to why the patient's drainage system doesn't work as well as we would like.
There are other secondary causes of the disease, such as trauma or glaucoma associated with diabetes, other types of vascular problems or other systemic diseases like arthritis.
What are the symptoms of glaucoma?
In the vast majority of cases, which are typically a kind of glaucoma called open angle glaucoma, there really are no symptoms early on. There is really nothing that the patient would notice. Later, when the optic nerve has been damaged, the patient might notice because the vision is impaired.
There also is a type of glaucoma called angle closure glaucoma that can cause severe pain or sudden vision loss. This accounts for 10 percent of the glaucoma in this country. I say, "In this country," because different types of glaucoma have different prevalences in different countries - all based upon ethnic backgrounds.
How is glaucoma diagnosed?
Most glaucoma is diagnosed when a patient gets a complete eye exam during which a lot of things are measured: vision, eye pressure, the thickness of the cornea, health of the optic nerve. And it can be diagnosed in visual field testing, which measures peripheral vision. There are also a lot of new computerized testing machines that actually examine the optic nerve and can tell us whether there is damage from glaucoma or not.
Is there an association between diabetes and glaucoma?
There probably is a small association, but the reason people often associate glaucoma with diabetes is that the [diabetes] patients typically are referred to a doctor, so the glaucoma is diagnosed.
Can anything be done to prevent glaucoma?
If you are going to get glaucoma, you are going to get glaucoma. We can't prevent it. However, if we catch it early enough, we can prevent you from having visual damage if the glaucoma is treated and followed appropriately.
How is glaucoma treated?
Most glaucoma treatments involve eye drops, which in many cases are only needed once a day. However, in more severe cases, the patients may need to use multiple eye drops two and three times a day. If the drops don't work, there are laser surgeries that can be used to treat glaucoma.
And those who can't be treated with laser surgery can be treated with traditional eye surgery done with very small cutting instruments to create new drainage channels to allow the pressure to be controlled.
What do you typically tell patients with glaucoma?
That glaucoma tends to be a very slowly progressive disease, and we would like to treat it as soon as possible. The more damage they have when diagnosed, the harder it is to treat them over the years.
Many patients with glaucoma live their entire lives without any visual disability whatsoever as long as they get their treatment and follow it. The patients who progress tend to be people who may not take the medications as prescribed and who don't come for their follow-up as recommended.
Does glaucoma occur in children?
In most cases, glaucoma doesn't really get diagnosed until people are in their 50s, 60s or 70s. Certain children can have a kind of glaucoma called congenital glaucoma, and they may need surgery when they are only days old. Childhood glaucoma is very, very rare and tends to occur in one in every 30,000 to one in every 50,000 births.
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