Age-related macular degeneration (AMD) affects nearly 200 million people worldwide and
is the most common cause of permanent vision loss in elderly adults in the United States. It is expected to become more common as the population gets older.
The part of the eye that is affected in AMD is the macula, which is part of the retina, the tissue inside our eye that captures light and send signals to the brain to help us see. The macula is important for our central vision and helps us see fine details. In AMD, waste products that the eye cannot clear build up in the macula and cause blurry, distorted vision.
Some people are more likely to develop AMD than others. AMD is more common in the elderly and those who have high blood pressure, high cholesterol, and heart disease. Genetics also plays a role in AMD, so having a family member with AMD may make you more likely to develop AMD. Smoking increases the risk of AMD. Compared to non-smokers, people who currently smoke are 3-5 times more likely to develop AMD and can make AMD worse in people who already have it. Even former smokers are twice as likely to develop AMD. Behaviors that can protect someone from AMD include avoiding smoking, protection from excessive sunlight exposure with sunglasses and hats, and eating a healthy diet with lots of fruits and vegetables.
There are 2 types of macular degeneration: dry AMD and wet AMD. Dry AMD slowly worsens over time, and the vision slowly worsens too. There is no current treatment for dry AMD, but an optometrist might recommend certain eye vitamins that can help keep it from getting worse. People with early dry AMD can still have good vision, but because it can get worse over time, it is important to have regular checkups with an optometrist at least once a year. The doctor will dilate the eyes and possibly take some scans of the macula to look for AMD or track its progress over time. More advanced dry AMD can cause severe loss of the central vision and difficulty with contrast. Contrast is important for us to recognize faces and to walk around safely.
Dry AMD can turn into wet AMD if there is bleeding in the macula, and wet AMD causes the vision to suddenly worsen. If the optometrist diagnoses a patient with wet AMD, they will recommend the patient to an ophthalmologist to be treated with a medicine that is injected into the eye. People with wet AMD usually need regular injections to help clear the bleeding from the macula.
Both dry and wet AMD can cause permanent damage to the macula and vision. However, AMD by itself does not cause total blindness because the peripheral or side vision is still present. If the poor central vision in AMD makes activities of daily life difficult, an optometrist may recommend the use of low vision devices or low vision rehabilitation. Low vision devices like hand-held magnifiers and electronic magnifiers can help with reading. A low vision optometrist can also recommend strategies to make doing tasks around the house or at work easier. Low vision services can also help those with vision loss from other conditions like glaucoma, retinitis pigmentosa, or a stroke.
References:
1. Gheorghe A., Mahdi L, Musat O. (2015). Age-Related Macular Degeneration. Romanian Journal of Ophthalmology. 59(2), 74-77.
2. Rafieetary M., Haynes J., Attar R. (2019). My Patient Has AMD… Now What? Review of Optometry. https://www.reviewofoptometry.com/article/my-patient-has-amd-now-what.
3. Stahl A. (2020). The Diagnosis and Treatment of Age-Related Macular Degeneration. Dtscj Arztebl Int. 117(29-30), 513-520.
