The most common vision problems are "refractive errors." Refractive errors occur when the shape of the eye keeps light from focusing directly on the retina. The length of the eyeball (either longer or shorter), changes in the shape of the cornea, or aging of the lens can cause refractive errors. Most people have one or more of these conditions. Refractive errors can make it harder for you to see things clearly but don't cause any loss of vision. This type of vision problem can be corrected with prescription eyeglasses, contact lenses, or, in some cases, surgery.
Low vision, or vision loss, means that even with glasses, contact lenses, medicine, or surgery, you still have problems seeing. Low vision can result from a variety of diseases, disorders, and injuries that affect the eye. The most common causes of low vision among adults in the United States are:
Diabetic retinopathy (ret-uhn-OP-uh-thee), in which diabetes damages the tiny blood vessels inside your retina (the light-sensitive tissue at the back of your eye).
Age-related macular degeneration, in which cells in the retina that allow you to see fine detail die.
Glaucoma, in which the fluid pressure inside your eyes slowly rises, damaging the optic nerve (the nerve that carries visual information from the eye to the brain).
Cataract, which is a clouding of the lens in your eye. The lens focuses light coming into the eye onto the retina.
Although these eye diseases are more common among older people, vision loss is not a normal part of aging. Sometimes, vision loss can be prevented. Routine eye exams can spot vision problems early. Prompt treatment can sometimes prevent vision problems from getting worse.
If you have some vision loss, visual aids such as special glasses and large print books can make life easier. You may need to learn new ways of doing things to make the best use of your remaining vision. Seek help for feelings of depression or anxiety, which are common in people losing their vision.
People with no vision also have many resources to keep them living independently. Braille books and computer programs that convert text into speech are examples of assistive technologies. Many people who are blind or have low vision rely on service animals, such as a Seeing Eye dog, to help them live independently.
Helping a Loved One - This guide is written for the loved ones of those with low vision. It provides strategies to help you communicate more effectively with your loved one and other related resources.
Low Vision - This publication provides information on low vision, including an explanation of the different risk factors and causes. It also provides information on the different signs and symptoms and possible rehabilitation techniques to correct low vision.
Vision Impairment - this web page links to information on vision impairment, including prevalence, causes, and the economic impact.
What You Should Know About Low Vision - This booklet helps people with vision loss and their families and friends better understand low vision. It describes how to get help for vision loss and tips for living safely and more independently.