Most people can continue to manage well when vision changes are small but, as changes in vision become greater, people experience more and more difficulty continuing normal everyday activities, even with glasses or contacts. Low vision is most often associated with the elderly.
Low vision describes a significant visual impairment that can’t be fully corrected with glasses, contact lenses, medication or eye surgery. A change in eyesight between 20/60 and 20/190 is called being partially sighted or having low vision. An eye test that scores 20/200 or worse means a person retains some sight but is classified as legally blind.
Naturally, a significant loss of eyesight makes everyday tasks more difficult. Someone with low vision will have trouble reading, writing, shopping, watching TV, driving a car or recognizing faces.
Causes of Low Vision
Many diseases and conditions can cause low vision. These include:
- Birth defects
- Injuries
- Aging
- Cataracts
- Glaucoma
- Damage to the optic nerve
- Diabetic retinopathy
- Retinitis pigmentosa
However, low vision is more commonly due to scarring because of a deterioration of the central part of the retina, known as macular degeneration. Because there are so many diseases and conditions that can result in low vision, it’s very important to have a complete eye exam by a medically trained eye doctor called an ophthalmologist, regularly.
Who is At Risk?
Although low vision can happen at any age, by far the greatest number of people who have low vision are elderly and the vision impairment is most often due to a change in central vision. Sometimes, low vision is associated with the loss of peripheral (side) vision when it’s close to the center. This is known as tunnel vision.
In a few instances, low vision is associated with a loss of colour vision or difficulty adjusting to changes in brightness within the field of vision.
Help for Low Vision
An optometrist may refer a patient to other specialists once the cause of low vision is identified. He may also suggest low vision aids such as magnifying glasses or special, strong reading glasses.
Increased lighting, properly positioned, is essential and tinted lenses can be used to reduce the glare from bright sunlight.
The Low Vision Specialist
If you are referred to a low vision specialist, she will evaluate the degree and type of vision loss you have, prescribe the appropriate low vision aids and help you learn how to use them. Some of these aids are:
- Lighted hand-held magnifiers
- Digital desktop magnifiers
- Bi-optic telescopes
- Hand-held digital magnifiers for shopping or eating out
- Software that simplifies computer use
- Special light fixtures
- Signature guides for signing cheques
Other helpful resources include large-print books, magazines, newspapers and playing cards. There are also telephones with large-print dials and calculators with large characters.
When necessary, you may also be referred to a mental health professional and/or a mobility coach to help you cope with your vision loss.
