People who wear glasses or contact lenses typically do so to correct impairments related to the anatomy of certain structures of the eye, namely the shape of the cornea or the length of their eyeballs.
Conditions That Can Be Corrected With Lenses
People who are shortsighted, or myopic, for example, have longer or more curved eyeballs. When light enters the eye, it reaches a focal point before hitting the retina. As a result, the image lands on the retina already out of focus. A myopic eye typically has too much light focusing power, so the prescription to correct myopia would involve taking away some of this power. Most children and young adults wear glasses to correct shortsightedness, far-sightedness, or astigmatism. Only an optometrist, ophthalmologist, or orthoptist can measure and prescribe corrective lenses for these conditions.
After age 40, adults need more focusing power for tasks up close, such as reading. This condition is called presbyopia, and is a normal part of aging. The lens inside the eye, which is responsible for focusing on images up close, becomes weakened and loses its focusing power. Reading glasses such as those “over the counter” found in a pharmacy or grocery store provide this extra focusing power for reading.
Macular degeneration is an age-related eye disease that involves damage to the retina and often causes low vision. Since the damage to retina is not related to the shape of the cornea, the length of the eyeball, or the power of the lens, it cannot be corrected with eyeglasses or contact lenses. In certain cases of moderate vision loss, stronger reading glasses may help up to a point, because they have some magnification power. Most of the time, though, the patient will need magnification and illumination. Magnifiers and other optical devices must be prescribed by an eye physician, just as medications and rehabilitation therapies must be prescribed by a medical physician.
Low vision therapists are professionals certified by the Academy for Certification of Vision Rehabilitation and Education Professionals to work with people who have low vision. They have unique knowledge, skills, and training that enables them to work with people diagnosed with low vision. Occupational therapists with specialty certification in low vision are also recognized by the American Occupational Therapy Association as having the knowledge and skills to work with adults with low vision.