Understanding Low Vision
What is Low Vision?
The term low vision refers to eyesight that is poor even with the aid of eyeglasses, contact lenses, medicine, or vision correction. Low-vision sufferers typically have 20/70 vision or worse, or have significant damage to their peripheral vision. If their vision in the best eye is worse than 20/200, they may be considered legally blind. Unlike patients who are completely blind, however, people with low vision still have some useful vision. Everyday activities like reading, driving, and watching TV can become very difficult without low-vision aids.
Low vision may be the result of a birth defect, an injury, a stroke, or age, or it may be a complication of a disease such as macular degeneration. Twenty years ago, the most frequent cause of low vision was infectious disease. Today visual impairments are more common due to longer life spans—that is, more people live to an age at which it is normal to experience vision problems. In particular, macular degeneration has been on the rise as average life-span has increased.
Some people with low vision suffer from miniscule visual impairments, while others are almost completely blind. People with low vision sometimes lose the ability to distinguish colors. The problems created by low vision can cause stress and lead to depression, job loss, or worse. However, there are solutions for people with low vision. Friends and family can learn more about low vision in order to help their loved ones live normal lives. Community resources can be found nationwide, as can low-vision specialists to help educate and support people with low vision (see chart below).
Signs of Low Vision
- Difficulty distinguishing colors
- Difficulty reading
- Difficulty distinguishing objects
- Difficulty recognizing faces
- Difficulty seeing objects
- Difficulty seeing signs and posts
Photos of how people with low vision might see.
|What someone with Diabetic Retinopathy might see||What someone with Glaucoma might see|
|What someone with AMD might see||What someone with Cataracts might see|
Classifying Low Vision
According to the World Health Organization (WHO) low vision is classified as follows:
- 20/30 to 20/60: mild vision loss or near-normal vision
- 20/70 to 20/160: moderate visual impairment or moderate low vision
- 20/200 to 20/400: severe visual impairment or near total blindness
- 20/500 to 20/1,000: profound visual impairment or profound low vision
- More than 20/1,000: near-total blindness
- No light perception: total blindness
Legal blindness is also classified by the WHO. In the United States, anyone whose vision cannot be corrected better than 20/200 in their best eye, or who has 20 degrees or less of visual field remaining, is considered legally blind.
Low Vision Aids
Although there is no cure for low vision, there is such a thing as vision rehabilitation. Vision rehabilitation teaches a person with low vision how to accomplish everyday tasks with new devices like video magnifiers and talking watches, and it enables them to gain confidence in handling their impairment.
The first step should be visiting an eye doctor who specializes in low-vision care and who can determine the severity of the problem. Your eye doctor can also prescribe certain devices and advise you on how to adapt your lifestyle to your impairment. These devices can help you read better, allow you to identify objects, and even read to you. You can learn new ways of doing everyday activities like cooking and getting around the house or office. Here are some common low-vision aids:
- CCTV: Closed circuit television systems that include a video camera that magnifies objects and projects them onto a large screen for viewing.
- Bifocal glasses: These come with an extra-strong prescription-strength lens on the lower half of a pair of eyeglasses, which acts as a magnifier.
- Magnifying glass: Could be hand-held or set on a stand.
- Screen magnifier: A computer program that magnifies what is on a computer screen.
- Voice-response computer: This specialized computer uses voice recognition to allow a person to browse the Internet. It is available in free-standing form or as software that works with your existing computer.
- Screen reader: A computer program that reads text aloud.
- Wearable telescope: A telescopic lens that is added to a section of the distance lenses on a pair of glasses.
- Mobile phone organizer: This is a special cell phone with large buttons and voice-activated functions to make calls, browse the Internet, and take notes.
Low Vision Specialists
Low vision specialists are eye doctors, either optometrists or ophthalmologists, who specialize in treating people with low vision. If you have low vision, your regular eye-care provider may refer you to a low vision specialist for treatment. You will be given an eye exam to determine whether glasses would help your vision.
Typically, the refractive test performed by a low-vision specialist differs from one performed by a general eye doctor. For example, special devices like telescopes may be used to arrive at an optimized glasses prescription. You may also be given a side-vision test, also known as a visual field test, and the eye doctor may watch your eyes closely as your read, in order to see how your eyes move. Each of these tests is designed to figure out how your vision can be optimized to allow you to become more independent. Your low-vision specialist will assess the functional needs, your capabilities, and the limitations of your visual system.
Some low-vision specialists work with occupational therapists. Occupational therapists are trained to help you adapt to your level of vision around your home or during activities you enjoy. Occupational therapists may come to your home to help you arrange your furniture. This is done to ensure that you are safe and can move around without obstacles.
Low Vision Resources
For more information and help with low vision, visit the following web sites:
|Low Vision Resource Website||Description of Resource|
|www.aao.org||The American Academy of Ophthalmology sponsors the National Eye Care Project, an outreach program that provides medical eye care to people who need access to an ophthalmologist.|
|www.afb.org||The American Foundation for the Blind; this is a non-profit organization that lists resources for people with impaired vision. Its web site features online forums to connect with others with low vision.|
|www.lighthouse.org||Lighthouse International is a non-profit organization that provides low-vision services to those with limited vision; it is located in the New York area.|
|www.loc.gov/nls||The National Library Service for the Blind and Physically Handicapped is a division of the United States Library of Congress. It organizes a national network of libraries that provides audio and Braille materials to legally blind borrowers by U.S. Postal mail.|
|www.navh.org||The National Association for the Visually Handicapped serves people with low vision. It provides large-print reading materials and low-vision aids; offices are located in San Francisco and New York.|
|www.preventblindness.org||Prevent Blindness America is a volunteer organization with local chapters throughout the United States. Its web site contains fact sheets about eye problems, eye safety and health, and living with low vision|
|www.visionaware.org||Vision Aware is a web site that lists helpful resources for people living with limited vision.|
|www.ocusource.com||OcuSource is an Internet resource for low-vision products, local resources, and professionals.|
|www.blindcanadians.ca||The Alliance for Equality of Blind Canadians serves to increase awareness of rights and responsibilities so that blind, deaf-blind, and partially sighted people can have equal access to the benefits and opportunities of society.|
|www.cnib.ca||The Canadian National Institute for the Blind is the primary source of support, information, and most importantly, hope for all Canadians affected by low vision or vision loss.|
* Chart courtesy of Reader’s Digest Guide to Eye Care, pg 80
Helping Others with Low Vision
There are several things you can do to help someone with low vision function or perform everyday tasks. Take a look at this list of tips:
- Always identify yourself when walking into a room.
- Never rearrange a room or the belongings of someone with low vision without their knowledge.
- Ensure that lighting is appropriate or matches the person’s preference.
- Use texture when labeling things; use puffy fabric paint, tape, or nail polish to mark dials, thermostats, or other objects.
- Use contrast wherever possible to make tasks easier, such as writing labels with black marker.
- When describing food on a plate, describe its location in a clock-hour format; for example, carrots are at 2 o’ clock and steak is at 6 o’clock, etc.
- When walking together, allow the person with low vision to hold onto your elbow, and verbally notify them of upcoming steps or changes in the pathway.
- Involve a person with low vision in the arrangement of items in the home, such as furniture in the living room or items in a medicine cabinet.
Talking to Your Eye Doctor
Here are some questions to ask your eye doctor about low vision:
- Which low-vision aids do you think will work best for me?
- How much do low-vision aids cost?
- Can you refer me to a community resource? Does this resource have specialists, aids, etc? Where in town are they located?
- Do you know of any new low-vision products on the market? What are some products that may be available in the future?
- Would I benefit from having an occupational therapist come to my home to help me organize my home and set up a daily routine?
- J. Weizer, MD; J. Stein, MD, MS “Reader’s Digest Guide to Eye Care” (Quantum Publishing, Ltd, 2009) 77-80
- The Low Vision Gateway, Low Vision Rehabilitation http://www.lowvision.org/
- J. Anshel, MD “Smart Medicine for Your Eyes” (SquareOne Publishers, 2011) 18; 261-263
- J. DiGirolamo, MD “The Big Book of Family Eye Care” (Basic Health Publications, Inc., 2011) 165-166