As macular degeneration progresses, central vision worsens, causing blurriness and sometimes a blind spot called a "scotoma." The patient may already own bifocals prescribed to improve near and distant vision. However, when vision loss is severe, an optometrist who specializes in evaluating and treating people with low vision may recommend special reading glasses, a magnifier or electronic devices that enable the patient to read and write.
Low-Vision Reading Glasses
Not every patient with severe vision loss is a candidate for using reading glasses. These glasses are typically thick, heavy and require holding the reading material very close--inches away from the face. Patients must be trained to move the reading material rather than the eyes in order to avoid the scotoma and make best use of the peripheral vision that isn't affected by the disease. Many people with macular degeneration find learning how to use the glasses challenging and tiring. However, some people are extremely motivated to be able to read--at least for short periods--and benefit from reading glasses.
Magnifiers
Many types of magnifiers are on the market. The ones sold in office supply or drug stores are generally quite weak and may only double the size of what is viewed. However, magnifiers sold through low-vision stores, catalogs, websites or prescribed by optometrists can magnify objects 5 to15 times. The greater the magnification, the smaller the reading area will be. That means the person has to move the magnifier rapidly in order to read with any fluency. Another consideration is whether to buy a hand-held magnifier or consider what is called a "stand" magnifier, which is placed directly on top of the reading material. Stand magnifiers are more expensive but easier to use. Both stand and hand-held magnifiers can be bought with built-in lights. Patients should consider trying various types of magnifiers before making a purchase by visiting a low-vision store or an optometrist who can explain the benefits of various magnifiers and recommend the best strength.
Electronic Devices
Electronic devices offer many options that make reading easier, such as enlarging the letter size and providing color contrast options. Patients can also purchase magnification screens that fit over a computer monitor, enlarging the entire viewing area. In addition, popular computerized games such as Scrabble or Solitaire can be purchased in an enlarged format. Electronic devices called closed-circuit televisions (CCTVs) enable users to place reading material on a sliding table while reading the enlarged print on the screen above it. This setup can assist with writing. For example, a check can be placed on the table (which can be stabilized) and filled out as the person views her hand movements on the screen. Other electronic devices include smaller, portable machines that magnify text and machines that read text out loud to the blind.
References
- "Coping with Vision Loss"; Bill Chapman; 2001.
- "Low vision Rehabilitation"; Mitchell Scheiman; 2007.
- "Foundations of Low Vision: Clinical and Functional Perspectives"; Anne L. Corn and Alan J. Koenig; 2004.
