Low Vision

Definition | Symptoms |  Treatment |  Clinic Information

Definition
Low vision is a term that denotes a level of vision that is 20/70 or worse and cannot be fully corrected with conventional glasses. Low vision is not the same as blindness. Unlike a person who is blind, a person with low vision has some useful sight. However, low vision usually interferes with the performance of daily activities, such as reading or driving. A person with low vision may not recognize images at a distance or be able to differentiate colors of similar tones.

Although low vision can occur at any stage in life, it primarily affects the elderly. However, low vision is not a natural part of aging. Although most people experience some physiological changes with age (presbyopia), these changes usually do not lead to low vision. Most people develop low vision because of eye diseases. Common causes of low vision, particularly with older adults, include macular degeneration, glaucoma, and diabetic retinopathy. When vision impairment is recognized early, treatment can be more effective, enabling people to maintain as much independence as possible.

You are legally blind when the best corrected central acuity is less than 20/200 (perfect visual acuity is 20/20) in your better eye, or your side vision is narrowed to 20 degrees or less in your better eye. People who are legally blind may still have some useful vision, just like people who have low vision. If you are legally blind, you may qualify for certain government benefits. It is estimated that approximately 17% of people over the age of 65 are either blind or have low vision.

Low Vision Exams
To determine the extent of your useful vision, you will need to have your eyes examined. The examination for low vision differs from typical eye examination. During a low vision examination, your doctor may administer the following tests:

• Refraction (to assess your vision and determine the prescription for your glasses, if glasses may be of any use)
• Visual field (to assess your peripheral vision)
• Ocular motility (to assess how well your eyes move)

Because low vision examinations may involve a variety of tests, they are often more time consuming than the standard examination. For instance, refraction may be done through a telescope or trial lens so you can judge which lens is best.

Symptoms

• Difficulty recognizing objects at a distance (street signs or bus signs)
• Difficulty differentiating colors (particularly in the green-blue-violet range)
• Difficulty seeing well up close (reading or cooking)

The symptoms described above may not necessarily mean that you have low vision. However, if you experience one or more of these symptoms, contact your eye doctor for a complete exam. Your eye doctor can tell the difference between normal changes which are common with age and changes caused by eye disease.

Treatment
The Kellogg Eye Center Low Vision and Visual Rehabilitative Services Clinic embraces a multi-disciplinary approach to the treatment of low vision. Ophthalmologists, optometrists and occupational therapists make up the team of health care professionals who will work with you starting with your vision examination, and continuing to work with you to identify treatment options, which include:

• Optical devices that will help you adapt, such as magnifiers, telephones or closed-circuit televisions.
• Techniques that will help you utilize your remaining vision.
• Environmental modifications to maximize your remaining vision.
• Adaptive non-optical devices, such as large-print cookbooks and talking watches.

Occupational therapy programs may last as long as several months or be as brief as one session. Occupational therapy treatment is available at Kellogg. Sessions include an evaluation of your environment and suggestions for modifying your home to enable you to become more independent and to improve safety.

Low Vision Aids
Many types of assistive devices are available to assist people with low vision. These items include special glasses and other magnification devices, and large print reading materials, shown above. Other communication aids include computer software and various other technological devices.
These items include special glasses and other magnification devices, and large print reading materials, shown above. Other communication aids include computer software and various other technological devices.

Resources
The U-M Kellogg Eye Center has a number of publications available for our patients with low vision and their families. Helpful Hints for Families of the Visually Impaired is available in PDF format which can be viewed with Acrobat Reader. If you don't already have it on your computer you can download it for free by clicking here.

The Henderson library is open to use by patients and their families, members of the community, physicians and other health care providers. Please see the library for a list of low vision resources.

The Washtenaw Library for the Blind and Physically Disabled's online Resource Guide offers an alphabetical listing of businesses and agencies providing products and services to individuals with vision loss, including subject index. http://www.aadl.org/wlbpd/resources

Clinic Information
For more information, see the Low Vision and Visual Rehabilitation Clinic at the U-M Kellogg Eye Center.