Low Vision

None — Low vision (defined as 20/60 vision) is a type of vision impairment in which a person is unable to see clearly even with best correction from eyeglasses, contact lenses, surgery or other type of medical therapy. Researchers estimate about 1.5 to 2 million people have low vision. It's the third most common cause of functional impairment for Americans over 70. The loss of visual acuity can cause difficulty reading, performing many daily activities and sometimes working or driving.

There are many different causes of low vision. The four most common causes are age-related macular degeneration, glaucoma, cataracts and diabetic retinopathy. Age-related macular degeneration is caused by a deterioration of light sensitive cells in the macula, or central area of the retina. Glaucoma is damage to the ocular nerve, usually caused by increased pressure within the eye. Cataracts are a clouding of the lens of the eye. Diabetic retinopathy is damage to the blood vessels that nourish the retina.

Dealing with Low Vision

Jeffrey Sonsino, O.D., Optometrist with Vanderbilt Eye Institute in Nashville, TN says the leading complaint among people with low vision is the inability to read. Patients can often overcome the problem with any number of vision aids, like hand-held magnifiers, stand magnifiers, reading telescopes, and spectacle-mounted magnifying lenses. But Sonsino explains that smaller devices can be tiring to use because the hand must constantly move to pick up the print. Larger devices may help, but can be expensive and can't be easily carried around. A bright reading lamp also helps, but isn't portable.

Sonsino and his colleagues have developed a new type of eyeglasses to help people with low vision. The glasses combine the three factors needed for clearer reading: magnification to enlarge the image, prisms to keep the eyes straight and focused and LED lighting for bright illumination. The glasses are powered by rechargeable batteries and designed so that when the bows are opened, the light automatically turns on. In a clinical trial of a small number of patients, users reported an 89 percent improvement in their reading ability.

Sonsino is now working with a manufacturer to produce the glasses. The researchers say affordability is important and they would like to sell the glasses for a lower cost than a standard pair of bifocals. The eyeglasses are expected to be available later this year and will initially be sold online. For information, go to http://www.LowVisionReaders.com. The low vision eyeglasses are expected to be available later this year and will initially be sold online. For information, go to http://www.LowVisionReaders.com.

For general information about low vision: American Foundation for the Blind American Optometric Association Lighthouse International National Eye Institute Prevent Blindness America®

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