Low vision

Low vision

 

What is low Vision?

Partial vision loss that cannot be corrected causes a vision impairment known as low vision. A person with low vision has severely reduced visual acuity or contrast sensitivity, a significantly obstructed field of vision -
or all three.

Signs of Low Vision:

  • Difficulty recognizing a familiar face
  • Difficulty reading -- print appears broken, distorted or incomplete
  • Difficulty seeing objects and potential hazards such as steps, curbs, walls, uneven surfaces and furniture

Low Vision = Useful Vision:

People with low vision usually retain some usable vision. An ophthalmologist or optometrist specializing in low vision can evaluate how you see and prescribe optical devices to maximize your remaining
vision. This functional vision assessment is an important step in helping improve your quality of life.

Improving Your Functional Vision with the Help of Devices:

Even with regular eyeglasses or contact lenses, a visual image -- whether a sentence from a book or a crosswalk at a busy intersection -- may appear distorted, blurred or incomplete if you have low vision. A
low vision doctor may recommend or prescribe devices such as magnifiers and tinted lenses to help you take full advantage of the sight you have. Non-optical devices such as large-print clocks and remote
controls, as well as signature and writing guides, are also popular.

 

Vision Rehabilitation - The Key to Safety and Independence:

If your vision loss can\'t be corrected by medical or surgical interventions, vision rehabilitation can help. Vision rehabilitation services equip you with skills and strategies to help you remain safe, independent
and active at any stage of life.
These services are provided by a multidisciplinary team of professionals who can introduce you to new methods of using remaining vision to help you maximize daily functioning and adjust to vision loss..
This team includes specially trained ophthalmologists, optometrists, social workers, nurses, occupational therapists, vision rehabilitation therapists, career counselors, orientation and mobility specialists, and others.

Low Vision Aids for Computer Users

In general, visually impaired people can use the same low vision aids for viewing a computer screen as they do for regular reading activities. These include eyeglass-mounted magnifiers, handheld magnifiers
and stand-alone magnifiers.
But also, special software has been developed to either display computer data in large print or read the material aloud in a synthetic voice.
These adaptive low vision devices let partially sighted people do the same computer-related tasks as fully sighted people — such as word processing, creating and using spreadsheets and viewing Web pages online.
Most computer operating systems and Internet browsers allow you to increase the size of Web pages and text on your computer screen to make them more visible to partially sighted users.
Here are a few simple tips for adjusting text size:

  1. In browsers such as Microsoft\'s Internet Explorer and Mozilla\'s Firefox, you can enlarge text on your screen by holding down the Control ("Ctrl") key on your keyboard and tapping the "+" key. (If you use Apple\'s Safari browser, use the Command key instead.)
  2. To return the text to its normal size, tap the "-" key while holding down the Control (or Command) key.
  3. You also can hold down the Control or Command key, then use the wheel on your mouse (see below) to increase or decrease the text size on your screen.
  4. Still another way to enlarge text on your screen is to use the "Text Size" or "Make Text Larger" command within "View" in the drop-down menu bar that appears at the top of your screen when you use popular software programs such as Microsoft Word and Outlook. On a Mac, the View menu has a "Zoom" option to enlarge text in Word and other applications.

Aids for Distance Vision: Functioning Outside the Home

Having low vision doesn\'t mean you have to stay indoors or rely completely on others to do your shopping or yard work. Many low vision devices are available to help your eyes function more effectively outdoors.
Light and glare sensitivity is a common problem for visually impaired people, especially among both pre- and post-op cataract patients and those with macular degeneration or diabetic retinopathy.
Special glare-reducing and blue-blocking lenses (so-called because they absorb the blue portion of the visible light spectrum) can be worn for more comfort outside, whether it\'s cloudy or sunny. They come
in light and dark gray, yellow, orange and various shades of amber.
Some are photochromic, so they lighten or darken according to the amount of sunlight they are exposed to. Lens colors, light transmission percentages and blue light absorption capabilities are all variables
that your eye care practitioner or low vision specialist will take into account when helping you decide which option is best for you.
Glare-reducing and blue-blocking lenses come in prescription sunglasses, nonprescription clip-ons for your regular eyeglasses and side-shielding "fit-over" styles that can be worn either alone or over your glasses.
For getting out and about, many partially sighted folks need assistance with their distance vision. Choices include handheld monocular telescopes (for use with one eye) and binoculars (for both eyes), as well
as eyeglass-mounted telescopes. You may need a prescription for these, as well as special training to use them effectively. A low vision specialist can help you with this.
New head-mounted electronic magnifying glasses provide automatic focusing, so whether you need near, intermediate or distance vision, they can help you handle most situations more easily than handheld telescopes.
The Jordy from Enhanced Vision is a portable device that can be worn like a pair of glasses to see near, far and anything in-between.
These glasses operate with a portable control unit and a rechargeable battery, so you can use them in stores, libraries or on the street. They provide good depth perception, which is missing from most other
types of low vision magnifiers.
Finally, canes generally are thought of as aids for completely blind people or people with trouble walking. But if you are missing part or all of your peripheral (side) vision, or if you\'re having a problem with Finally, canes generally are thought of as aids for completely blind people or people with trouble walking. But if you are missing part or all of your peripheral (side) vision, or if you\'re having a problem with
night blindness, canes can help you navigate unpaved areas and keep your balance.
This is very important, because falls are the leading cause of injury-related deaths among older people, according to the U.S. Centers for Disease Control.
Foldable or telescoping aluminum canes or walking sticks are light and sturdy and can be stored in a carrying case on your belt or stowed in a bag. Adding reflective tape to a cane makes it more visible to
drivers at night.

How to Live With Low Vision

Living with low vision can be challenging, although many devices are available to help people with this condition use their remaining vision to greatest advantage.
Eye care professionals use the term "low vision" to describe significant visual impairment that cannot be corrected with standard glasses, contact lenses, medicine or eye surgery.
Low vision includes loss of best-corrected visual acuity — to a level worse than 20/60 in the better eye, measured with a standard eye chart — or visual field loss such as tunnel vision or blind spots. It also

describes legal blindness and almost total blindness.
Low vision has a variety of causes, including eye injury, diseases and heredity. Sometimes low vision involves a lack of acuity, meaning that objects appear blurred. Other times, it involves a significant
loss of peripheral vision and visual field. Other symptoms of low vision include light sensitivity, distorted vision or loss of contrast. The eyesight of a person with low vision may be hazy from cataracts, blurred or partially obscured in the central visual zone because of macular degeneration or distorted and/or blurred from diabetic retinopathy. Also, people with glaucoma or retinitis pigmentosa can lose their peripheral vision and have difficulty seeing at night.Children as well as adults can be visually impaired, sometimes as a result of a birth defect or an injury. But low vision more commonly afflicts adults and seniors. Vision loss can be very traumatic, leading to frustration and depression.Many people who develop eye problems that cause low vision lose their jobs. According to Lighthouse International, among visually impaired Americans of ages 21 to 64, only 43.7 percent are employed. Among normally sighted people in this age group, 80 percent are employed.Not being able to drive safely, read quickly or easily see images on a television or computer screen can cause people with low vision to feel shut off from the world. They may be unable to get around town independently, earn a living or even shop for food and other necessities.Some visually impaired people become completely dependent on friends and relatives, while others suffer alone.That\'s a shame, because many ingenious low vision devices and strategies exist to help people overcome vision impairment and live independently.If you have a vision impairment that interferes with your ability to perform everyday activities and enjoy life, your first step is to see an eye care professional for a complete eye exam.Poor vision that cannot be corrected with eyeglasses or contact lenses could be the first sign of a serious eye disease such as age-related macular degeneration, glaucoma or retinitis pigmentosa. Or it could mean you are developing a cataract that needs removal. Whatever the case, it\'s wise to take action before further vision loss occurs.If your eye doctor finds that you have a vision loss that cannot be corrected with eyewear, medical treatment or surgery, he or she can refer you to a low vision specialist.Usually an optometrist, a low vision specialist can evaluate the degree and type of vision loss you have, prescribe appropriate low vision aids such as magnifiers, telescopes and video magnifiers, and help you learn how to use low vision aids.The low vision specialist also can recommend non-optical adaptive devices, such as large-face printed material, audio tapes, special light fixtures and signature guides for signing checks and documents.If necessary, your specialist or eye doctor also can refer you to a counselor or mental health professional to help you cope with your vision loss

Low Vision Aids for Reading

Finding a way to read comfortably is one of the most difficult challenges for visually impaired people. Many give it up altogether, because what used to be an enjoyable, effortless activity now requires thought, preparation and a lot of adjustment. For some people in this situation, reading is just no fun anymore.Even so, many low vision devices can make reading easier and more rewarding for people with macular degeneration, retinitis pigmentosa, tunnel vision and other low vision conditions. The most affordable are hand-held magnifiers, some of which contain small reading lamps for better illumination. Other magnifiers are mounted on height-adjustable stands or hang around the neck.Strong reading glasses come in full- or half-lens styles. Or you can obtain bifocals with high-power reading lens segments. Reading telescopes are another option. They can be hand-held or mounted onto special eyeglass frames with enhanced nose pads and padded bridges, so your nose will carry the weight more comfortably.Video magnifiers project printed material on a closed circuit television (CCTV) monitor or regular television or computer screen; you can sit as close to the screen as necessary and adjust the magnification, brightness, contrast and color of the display to your liking.Advantages of this system are that it doesn\'t add weight to your nose (as in the case of eyeglass-mounted scopes), and you can sit upright in a comfortable position, instead of leaning over a table.The disadvantage is that it costs more than a simple magnifier or pair of reading glasses. But considering the quality of life benefits that video magnifiers offer a person with low vision, the cost is probably worth it for most people.A more portable system is a device that rests on your reading material and magnifies it, projecting the image onto a pair of eyeglasses that you wear. You read the material on the glasses as you move the device across the page. You can also read curved surfaces, such as cans or pill bottles, so this device is useful for shopping.Some reading devices require a prescription from your eye care practitioner because they are custom-made for your particular needs. But consult your doctor before buying even nonprescription magnifiers, because he or she can tell you which low vision devices will work best for you, based on your activities and the lens power you require.

Good Lighting Is Essential

For many people with low vision, increasing the amount and type of ambient light can greatly improve reading ability. If you know someone who is visually impaired, check the adequacy of the lighting in their home — particularly in their favorite reading areas.Use the brightest light bulbs recommended for light fixtures. Purchase lamps with three-way sockets that allow the use of bulbs that can be increased to 150 watts for reading.Natural sunlight is the best lighting for reading. Arrange furniture so the person with low vision can sit near a window for daytime reading. For artificial lighting, purchase "full-spectrum" light bulbs. These bulbs emit light that more closely mimics natural sunlight than regular incandescent bulbs.Avoid harsh fluorescent lighting, which can cause glare — especially for anyone with low vision. Replace fluorescent desk lamps or kitchen lighting with halogen task lighting or full-spectrum bulbs for better comfort and visibility.People who suddenly find themselves with low vision often are surprised at how essential good eyesight is — not only for reading, but just to get through everyday life.For the visually impaired, something as simple as checking the time on their watch or being able to see the difference between a one-dollar bill and a ten-dollar bill can become a difficult chore.In addition to low vision devices and good lighting, inexpensive non-optical adaptive aids can assist with routine daily activities. These devices include:

  1. Large-print cookbooks
  2. Large-numbered playing cards, clocks, telephones and watches
  3. Electronic "talking" clocks, kitchen timers, thermometers, blood pressure meters and even pill bottles
  4. Large felt-tip pens and wide-lined paper for writing notes
  5. Wallets that separate different bill denominations into different pockets
  6. Color-coded pill boxes
  7. Voice-recording electronic organizers
  8. Signature guides


Many of these items can be found at your local drugstore, discount store or bookstore. Your low vision specialist can recommend retail sources for non-optical adaptive aids.