Low vision is the loss of sight that is not correctable with prescription eyeglasses, contact lenses, or surgery. This type of vision loss does not include complete blindness, because there is still some sight and it can sometimes be improved with the use of visual aids.
Low vision includes different degrees of sight loss, from blind spots, poor night vision, and problems with glare to an almost complete loss of sight.
There are two defined categories of low vision:
The ratio measurement of vision describes visual acuity, or the sharpness of vision, at 6 meters (20 feet) from an object. For example, having 20/70 vision means that you must be at 6 meters (20 feet) to see what a person with normal vision can see at 21 meters (70 feet).
Anyone can be affected by low vision because it results from a variety of conditions and injuries. Because of age-related disorders like macular degeneration and glaucoma, low vision is more common in adults over age 45 and even more common in adults over age 75. For example, one in six adults over age 45 has low vision; one in four adults over age 75 has low vision.
The most common types of low vision include:
There may be one or more causes of low vision. These are usually the result of disorders or injuries affecting the eye or a disorder such as diabetes that affects the entire body. Some of the most common causes of low vision include age-related macular degeneration, diabetes, and glaucoma. Low vision may also result from cancer of the eye, albinism, brain injury, or inherited disorders of the eye including retinitis pigmentosa. If you have these disorders or are at risk for them, you are also at greater risk for low vision.
An eye exam by your eye care specialist can diagnose low vision. You should make an appointment with your eye doctor if your vision difficulties are preventing you from daily activities like travel, cooking, work, and school. The tests the eye doctor will perform include the use of lighting, magnifiers, and special charts to help test visual acuity, depth perception, and visual field.
Some sight disorders, like diabetic retinopathy, can be treated to restore or maintain vision. When this is not possible, low vision is permanent. However, many people with low vision find visual aids helpful. Popular low vision aids include:
Some patients with retinitis pigmentosa who have no useful vision may be eligible for the Argus® II retinal prosthesis. This device partially restores vision to patients who have lost their sight. In some patients, the restored vision allows for them to independently navigate through doorways, sidewalks, sort light and dark colored laundry, or even read large letters.
Non-optical aids designed for people with low vision are also very helpful. Some popular non-optical devices include:
Visual aids improve both sight and the quality of life for many people. Talk to your doctor about where to purchase visual aids.
Low vision may be preventable for patients with diabetes, and some patients with macular degeneration and glaucoma may be treated to prevent the further vision loss.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition.
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