What is Low Vision

For those who ordinary eyeglasses, contact lenses or intraocular lens implants don't give clear vision, then an individual is considered to have low vision. Low Vision differs from blindness in that it refers to people who still have useful vision that can be improved with visual devices. Low vision generally means a person's vision does not meet their needs, whether their visual impairment be mild or severe.

What Causes Low Vision?

Although older individuals experience low vision the most, it can occur in a person at any age. Low vision can be caused by birth defects or prematurity, inherited eye conditions, injuries, diabetes, glaucoma, cataracts, and aging. The most common form of low vision is macular degeneration, which affects individuals as they age.

What are the Different Types of Low Vision?

Reduced reading or central vision is the most common form of low vision, although many people experience a loss in side (peripheral) vision or loss of color vision. Some individuals may have problems adjusting to light, contrast, or glare. Different types of low vision may require different kinds of assistance, and people born with low vision may have different needs than those who develop low vision later in life.

What Types of Devices Can Help a Person With Low Vision?

A low vision device is an aid that improves vision, although there is no one device that will restore normal vision in all circumstances. For many people different devices are needed for different situations or purposes. Since each device may have a different use, it is best to try a device before purchasing it to make sure it is useful.

There are two types of low vision devices:

• optical
• and non-optical.

Optical Low Vision Devices

Optical low vision devices should not be confused with eyeglasses, but are different in that they use lenses or combinations of lenses to provide magnification. The main types of optical devices include:

* Magnifying Spectacles

These are like eyeglasses but are stronger, and when used a person needs to hold reading material very close to their eyes. Magnifying spectacles are designed for close work and since they are spectacle mounted allow both hands to be free to hold materials.

* Hand Magnifiers

These devices are familiar to most people and when used correctly allow a person to hold reading material at a more normal distance. Although these can be purchased in many stores, if a person's vision impairment is severe or a more complicated eye condition(s) it is best to work with a vision rehabilitation specialist to determine which type and strength is best. Many stores also do not carry some of the stronger magnifiers. Some of these type also have lights within them to make material easier to see.

*Stand Magnifiers

Stand magnifiers rest on the reading material itself so that a person does not have to adjust the distance. Some of these also have self-contained lights.

*Telescopes, Binoculars, and Monoculars

These aids typically are used for more distant vision such as watching television, movies, reading signs, etc.. Some are mounted in spectacles, clip on regular eyeglasses, and others are hand held. Monocular magnifiers are best used if a person only has useful vision in one eye, or if one eye is significantly better than the other.

* Closed-Circuit Television and Computer Equipment

A closed-circuit television enlarges an image on a television screen. These devices have adjustable magnification and contrasting images, with some models relying on a person to move the "camera" over the material and other types using a table that slides under the "camera". There are also different computer programs that will scan material onto a computer screen and enlarge it, or enlarge material within the computer itself.

Non-Optical Devices

Non-optical devices refers to aids which are not based on lenses and magnification but rather aids which may be enlarged to make their viewing or the activity easier to use. Such devices include:

• Large print books, newspapers, and magazines
• Writing guides for checks, envelopes, and signature
• Large face/print playing cards
• Enlarged telephone dials
• Large/bold faced watches
• Wide space/bold line writing paper
• Talking machines, including clocks, watches, timers, calculators
• Computers and machines that scan printed material and read the scanned material aloud

Also, holding something very close to your eyes or sitting as close as possible to the television screen are examples of the simplest non-optical aids. Contrary to popular belief, doing these will not cause eye damage.

Why Is Lighting So Important to Low Vision?

Correct and useful lighting is extremely important to individuals with low vision. For example, a 60 year old person may need twice the lighting she or he needed when doing the same task at age 20. As well as the amount of light being important, the direction and focus of the light are important to reduce glare or shadows. Some tips for lighting include:

• Place the light source close to the reading material for greater visibility.
• High intensity lights with adjustable arms work well.
• Visors and hat brims can help block annoying overhead light.
• Absorptive lenses are good for controlling glare.

Where Can A Person With Low Vision Receive Help?

After having a complete medical eye examination by an eye care specialist, a person should try to find a low vision clinic or eye specialist with training and background in low vision. Due to the complexity of many eye problems and the amount of time needed for a thorough clinical low vision evaluation there are not very many ophthalmologists or optometrists who specialize in low vision. A good low vision assessment usually involves at least 45 minutes from a doctor, and at least another 45 minutes from a trained vision rehabilitation therapist. Many times such appointments require more than 90 minutes total in order to determine any prescriptive device as well as other aids for near vision, distant vision, and what is best for the various environments a person is in. If you, or someone you know, has a vision problem that interferes with daily activities and could benefit from Low Vision Services, go to the Make A Referral link or call the Society at 314-968-9000.

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