Age Related Macular Degeneration (AMD)

Macular degeneration is caused by the deterioration of the central portion of the retina, the inside back layer of the eye that records the images we see and sends them via the optic nerve from the eye to the brain. The retina's central portion, known as the macula, is responsible for focusing central vision in the eye, and it controls our ability to read, drive a car, recognize faces or colors, and see objects in fine detail.

Age related macular degeneration (AMD) is one of the most common causes of poor vision after age 60. Although the specific cause is unknown, AMD seems to be in part due to aging. While age is the most significant risk factor for developing AMD, heredity, blue eyes, high blood pressure, cardiovascular disease, and smoking have also been identified as risk factors. AMD accounts for 90 percent of new legal blindness in the US.

Forms of Macular Degeneration

Dry Form

Nine out of 10 people who have AMD have the dry form, which results in thinning of the macula, the area of the retina responsible for central vision. Dry AMD takes many years to develop.

Wet Form

The wet form of AMD occurs much less frequently (one out of 10 people) but is more serious. 

Symptoms

The visual symptoms of Age Related Macular Degeneration involve loss of central vision. While peripheral vision is unaffected, one loses the sharp, straight-ahead vision necessary for driving, reading, recognizing faces, and generally looking at detail. Imagine being able to see a clock on the wall but being unable to make out the time or unable to read because you could not see parts of words on the page.

Promising Age Related Macular Degeneration research is being done on many fronts. In the meantime, high-intensity reading lamps, magnifiers and other low-vision aids help people with AMD make the most of remaining vision.

Risk Factors

Aging

Approximately 10% of patients 66 to 74 years of age will have findings of macular degeneration. The prevalence increases to 30% in patients 75 to 85 years of age.

Smoking

The only environmental exposure clearly associated with macular degeneration is tobacco smoking. Not only does smoking increase the risk of macular degeneration development, current or ex-smokers cannot take vitamin supplements that have beta carotene because the risk of lung cancer increases if they do so.

Family History of Macular Degeneration

Macular degeneration appears to be hereditary in some families but not in others. Approximately one fourth of all late-stage macular degeneration appears to have a genetic basis. The lifetime risk of developing late-stage macular degeneration is 50% for people who have a relative with macular degeneration.

Other Possible Risk Factors:

• Exposure to sunlight, especially blue light
• Hypertension
• Cardiovascular Risk Factors (high cholesterol, obesity)
• Female gender
• Non-hispanic whites
• Hyperopia (Farsightedness)