Elder Care Interprofessional Provider Sheets

Macular Degeneration

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

December 2017

TIPS ABOUT MACULAR DEGENERATION

  • Recommend smoking cessation, maintaining a healthy weight, and consuming a healthy diet, all of which reduce the risk of AMD.
  • When drusen are seen on ophthalmoscopic exam, suspect AMD and refer the patient to an ophthalmologist.
  • Consider using an Amsler Grid for preliminary assessment of older patients with visual complaints.
  • Individualize vitamin and mineral therapy for AMD (see text) to avoid adverse effects.

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.  

Table 1. Stages of Age-Related Macular Degeneration
Stage
Findings on Retinal Examination
Early
Small numbers of drusen
Intermediate
Numerous drusen, some large; geographic atrophy not involving the macula
Advanced non-neovascular
Drusen and geographic atrophy involving the macula
Advanced neovascular
Choroidal neovascularization that may result in hemorrhage or retinal detachment

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)

Table 2. Symptoms of Age Related Macular Degeneration
Early Symptoms
Late Symptoms
Need for brighter light
Difficulty recognizing faces
Decreased intensity of colors
Hazy overall vision
Metamorphopsia (wavy distortions)
Blurred or blind spot in central vision

 

Table 3. Vitamin and Mineral Doses Used for Intermediate and Advanced AMD
Vitamin C
500 mg/day
Vitamin E
400 IU/day
Beta-carotene
15 mg/day
Zinc oxide
80 mg/day
Cupric oxide
2 mg/day

References and Resources