Glaucoma
Glaucoma is the second leading cause of blindness in North America, behind diabetes. In glaucoma, the optic nerve (the nerve carrying information from the eye to the brain) is damaged by a build-up of fluid in the eyeball.
The front of the eye is filled with a clear liquid that supplies the eye with oxygen and nutrients and keeps it inflated. A gland behind the upper eyelid produces a steady supply of this liquid, and it normally drains out through a mesh of tiny holes behind the lower eyelid. In glaucoma, the liquid is produced normally, but it cannot drain out of the eye. This causes pressure to build up in the eye, pressing on the optic nerve. The nerve cells slowly lose their blood supply, eventually dying. The outer nerves fail first, so vision loss tends to start at the edges, progressing to "tunnel vision" and blindness. Many people don't notice this at first, and there's usually no pain, so glaucoma is often quite advanced before it's detected.
The good news is that with early treatment, vision loss can be minimized or prevented. Because glaucoma isn't obvious, it's vital to get your eyes checked regularly, especially if you have any of these risk factors:
- family history of glaucoma
- you are of African descent
- advancing age
- nearsightedness
- previous eye injury
- high blood pressure
- diabetes
- long-term use of prednisone, cortisone, or other steroids
Adults should have their eyes checked every one to two years up to the age of 65, and every year after that. But if you have any of these risk factors, you should go as often as your eye care professional recommends. At the check-up, the optometrist will measure the pressure in your eye, look at the optic nerve for signs of damage, and check your peripheral vision. If glaucoma is suspected, you will probably be referred to an ophthalmologist (a physician specializing in eye disorders) for treatment. Glaucoma is usually treated with eye drops that lower the pressure in the eye. In some cases, surgery may be needed.
Taking the eye exam
Did you know that it's important to have regular eye exams, even when your vision seems to be fine? Regular check-ups can detect "silent" conditions that could lead to blindness (such as glaucoma) so that they can be treated early. Children who are having trouble learning or reading at school may have a vision problem that can be found with a check-up and corrected. Regular check-ups also help you keep up-to-date on the latest information about eye care.
The Canadian Association of Optometrists recommends the following schedule for eye exams:
- Infants and toddlers (birth to 24 months) - By age 6 months
- Preschool (2 to 5 years) - At age 3, and before entering elementary school
- School age (6 to 19 years) - Every year
- Adult (20 to 64 years) - Every one to two years
- Older adult (65 years and older) - Every year
People who may be at higher risk of vision problems may need to have more frequent eye exams. In addition to regular eye exams, you should also have an eye exam if you have any concerns about your vision, or if you injure your eyes in any way. You might need a checkup if:
- you have trouble reading small print or doing close work such as sewing or crafts
- you need to hold newspapers and books further away in order to read them
- you get headaches or tired, burning eyes after reading or working on a computer
- you have difficulty seeing at night or seeing street signs while driving
- your eyes are irritated, dry, red, or sensitive
- you see spots, flashes of light, or floaters
- you have recently been diagnosed with diabetes
- you are in school and are having trouble reading or learning
- you have started handling chemicals, using power tools, or engaging in sports that may be hazardous to your eyes
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