The macula is the central part of the
retina and is responsible for reading and other tasks that require the detection of fine
detail. Macular Degeneration occurs when the macula becomes either thin (dry macular
degeneration) or elevated and uneven due to leaking blood vessels under the retina (wet
macular degeneration). People with macular degeneration have mostly peripheral vision
and blurry or no central vision.
While the causes of macular degeneration are still not
well understood, smoking has been shown to be
a major risk factor - probably the most important controllable
risk factor. Even second-hand smoke is implicated.
If you don't smoke, don't start.
If you smoke, stop.
Diabetes can damage the capillaries of
the retina, causing the retina to leak fluid onto the macula, and making the retina
swell and blur vision. Without treatment, new blood vessels will grow along the retina
and bleed, potentially destroying the retina. People with diabetic retinopathy have
blurred and spotty vision. A comperhensive
eye exam can detect the early stages of diabetic
retinopathy before symptoms appear.
A cataract is a clouding of the eye's lens. Because the
lens focuses the eye, a person's vision blurs when the lens becomes cloudy, just as
if one was trying to look at something through a waterfall. Glare can also be a significant
problem for people with cataracts.
Glaucoma is an eye disease in which the normal pressure
in the eye rises. This pressure can cause damage to the optic nerve and other parts of
the eye. People with the most common type, open angle glaucoma, lose their
peripheral vision, and as the disease worsens, the field of vision narrows.
glaucoma can usually be controlled, but it is
important to catch it before it does irreparable
damage. You should have a dilated-eye exam
regularly, which will include a check that glaucoma
isn't sneaking up on you.
The above are four of the most common causes of
low vision, but there are more. If you have
low vision, your eye doctor can help you figure out
why. Whether or not you have low vision,
your eye doctor can recommend ways to minimize the
risk of your eyesight getting worse.
For more information:
Glaucoma?" from the Laser Eye Surgeons Directory provides a brief
overview of glaucoma and links to sources of more detailed information.