Macular degeneration is a disease that primarily affects older people and causes loss of central vision. The macula is in the center of the retina, which is the light-sensitive part of the eye that sends nerve signals to the brain. Age-related macular degeneration (AMD) always begins with the much more common dry form, which may or may not advance into the wet form. Treatment varies depending on whether the disease is in the early, intermediate or advanced stage.
Early Stage Treatment
During the early stage of AMD, patients experience slightly blurred central vision that makes it difficult to recognize faces. Treatment consists of environmental adaptations such as increasing light, reading large-print books, use of bold-lined paper and magnification for tasks that require precision such as threading a needle. There is no medical treatment for early stage dry AMD that can delay vision loss or restore vision. Doctors, however, often instruct patients to perform a daily assessment by looking at what is called the Amsler Grid. By looking at the grid, a patient will be able to detect blurriness, distortion or blind spots (called scotomas) that indicate immediate need for treatment.
Intermediate Stage Treatment
Doctors may recommend that patients take a special high-dose formula of antioxidants and zinc during the intermediate stage of dry AMD to reduce the risk of developing advanced AMD. The National Eye Institute's Age-Related Eye Disease Study (AREDS) found that this formula slows the progression of the disease during this stage; however, this formula was not shown to be effective during the early stage of the disease. Antioxidants are nutrients such as vitamins, minerals and enzymes that counteract the damage of the oxidation process in animal tissue. The AREDS antioxidant formula includes vitamins C, E, A and zinc and copper. Treatment during this stage also includes further environmental modifications and adaptive devices such as large-numbered clocks, remote controls, telephones or timers, creating color contrast, reducing glare and use of magnifiers.
Advanced Stage Treatment
During the advanced stage of AMD, further breakdown of cells and tissue in the retina causes more severe loss of central vision. The blurred area gets bigger and larger so that the patient cannot read or recognize faces unless they are very close. There is no medical treatment for the advanced form of dry AMD. However, because only central vision is affected and peripheral vision remains virtually intact, therapy focuses on teaching patients how to best use peripheral vision for reading and other modifications such as listening to books on tape, tactile bumps that indicate settings on machines (such as ovens, stoves or washing machines) and use of strong magnification. Dry AMD can advance to the wet AMD during any stage of the disease. Wet AMD is always severe and is treated with laser surgery, photodynamic therapy and injections to prevent further vision loss.
References
- "Age-Related Macular Degeneration; What You Should Know"; National Eye Institute; 2003
- "Coping with Vision Loss"; Bill Chapman; 2001
- "Low Vision Rehabilitation"; Mitchell Scheiman; 2007
