Serena J. Scott, MD and Barry D. Weiss, MD, College of Medicine, University of Arizona

December 2017

Age-related macular degeneration (AMD) is the most common cause of irreversible blindness among older adults in the United States. The prevalence of AMD increases with age and, indeed, age is the strongest risk factor. AMD affects some 10% of individuals between 66-74 years of age, but the rate increases to 30% in those 75 and older. One of every 14 people over aged 75 has advanced AMD with significant visual impairment.

AMD is most common in whites, followed by Native Americans, Hispanics, Asians, and blacks. These racial differences may relate to the presence of genetic polymorphisms, which are thought to account for up to three-quarters of cases of AMD. Current or past smoking is also a strong risk factor for AMD, as are obesity, hypertension, cardiovascular disease, family history, high-fat diets, and low intake of antioxidants. 

Clinical Presentation

AMD progresses through stages (Table 1). In its earliest stage, AMD is often asymptomatic. As the disease progresses and symptoms develop, AMD can seriously impair vision because the disease involves the macula - the central area of the retina responsible for highest-resolution color vision. Early symptoms include the need for more light when reading and a decrease in the intensity of colors (Table 2). As AMD progresses, loss of central visual acuity occurs, and patients experience blurriness of printed words, difficulty recognizing faces, and, in later stages, blind spots in the central visual field. Central vision is required for activities such as driving, reading, watching television, and performing most activities of daily living.

Examination

A review by the Cochrane Collaboration found no evidence that routine screening changes outcomes for patients with AMD, and therefore routine vision screening of all older adults is not recommended. When older adults complain of visual symptoms, however, such as those in Table 2, AMD should be considered as a diagnostic possibility.

Physical exam findings in early AMD include the presence of drusen on funduscopic exam (Figure1). Drusen are small yellow or off-white extracellular protein and lipid deposits that form either in the tissue layer underneath the retina or on the optic nerve head. The exact cause of drusen is unknown, but its presence on the macula of the retina strongly suggests AMD. Referral to an ophthalmologist should be made to confirm the diagnosis.

Another office-based assessment that can be used to assess for AMD when older patients complain of visual symptoms is an Amsler grid (Figure 2). Patients view the grid through each eye separately and report if they see wavy distortions (metamorphopsia) or breaks in the grid pattern. Patients reporting such abnormalities should be referred to an ophthalmologist.  

Treatment and Prevention

All stages of AMD are treated with lifestyle modification to lower the risk of progression to advanced neovascular AMD.  Recommendations include smoking cessation, weight loss if overweight, control of hypertension, and increased dietary intake of antioxidants including beta-carotene, vitamins C and E and zinc.  Large-scale AMD studies suggest that supplemental vitamins and minerals (Table 3), in addition to dietary intake, can reduce the rate with which intermediate and advanced non-neovascular AMD progress to neovascular AMD. Use of these supplements should be individualized, however, because in other research, beta-carotene supplementation has been linked to lung cancer in smokers, and vitamin E has been linked to heart failure in people with diabetes or cardiac disease.

Neovascular AMD, also called wet macular degeneration, usually develops from dry AMD and presents suddenly and with rapid vision loss. This disease is frequently treated with intravitreal injections of anti-angiogenic agents (VEGF inhibitors), laser therapy, and/or a variety of experimental treatments and devices. More information about these treatments can be found in the references and resources listed below.

Visual Aids

For patients with severe visual loss, several visual aids are available.  These include video magnifiers, telescopes mounted on eyeglasses, and others.  Another issue of Elder Care addresses these visual aids. (See Low Vision Aids)

References and Resources

• American Academy of Ophthalmology. Age-Related Macular Degeneration, Preferred Practice Pattern. San Francisco: American Academy of Ophthalmology, 2008. 
• Bahadorani S, Singer M. Recent advances in the management and understanding of macular degeneration. F1000Res. 2017 Apr 20;6:519. 
•  Gemenetzi M, Patel PJ. A Systematic Review of the Treat and Extend Treatment Regimen with Anti-VEGF Agents for Neovascular Age-Related Macular Degeneration. Ophthalmol Ther. 2017 Apr 27.
• Jager RD, Meiler WF, Miller JW. Age-related macular degeneration. N Eng J Med. 2008; 358:2606-14.
• Smeeth LL, llife S, Community screening for visual impairment in the elderly. Cochrane Database of Systematic Reviews 2006. 
• Summary of study results from the Age-Related Eye Disease Study.  

Interprofessional care improves the outcomes of older adults with complex health problems

Elder Care Editors: Editor-in-Chief: Barry D Weiss, MD;  Deputy Editor: Mindy Fain, MD
 
 National Editorial Board: Theodore M Johnson II, MD, MPH, Emory University; Jenny Jordan, PT, DPT, Sacred Heart Hospital, Spokane, WA;  Jane Marks, RN, MS, FNGNA, Johns Hopkins University; Josette Rivera, MD, University of California San Francisco; Jean Yudin, CRNP, University of Pennsylvania
 
 Interprofessional Associate Editors: Carleigh High, PT, DPT; David Coon, PhD; Marilyn Gilbert, MS, CHES; Jeannie Lee, PharmD, BCPS; Marisa Menchola, PhD;  Francisco Moreno, MD; Linnea Nagel, PA-C, MPAS; Lisa O'Neill, DBH, MPH; Floribella Redondo; Laura Vitkus, MPH, CHES

Published by: The University of Arizona, PO Box 245027, Tucson, AZ 85724-5027  |  (520) 626-5800  | https://uofazcenteronaging.com

 This project was supported by the Health Resources and Services Administration (HRSA) of the U.S. Department of Health and Human Services (HHS) under grant number U1QHP28721, Arizona Geriatrics Workforce Enhancement Program.   This information or content and conclusions are those of the author and should not be construed as the official position or policy of, nor should any endorsements be inferred by HRSA, HHS or the U.S. Government.