Macular degeneration: types, causes, symptoms and treatments
What is macular degeneration?
Macular degeneration — also called age-related macular degeneration (AMD or ARMD) — is a vision change that can gradually create blurry vision over time.
AMD affects the macula, the small central area of the retina that maintains our sharpest vision. The health of the macula determines our ability to read, recognize faces, drive, watch television, use a digital device and perform any other detailed visual task.
A patient with age-related macular degeneration gradually loses central vision but maintains peripheral or side vision. Blindness is rare in AMD.
Macular degeneration is the leading cause of vision loss among older Americans. According to statistics, one-third of males and one-quarter of females over 75 have some form of AMD.
The prevalence of AMD and the severity of vision loss increases with age, according to the American Optometric Association.
AMD may occur in one or both eyes and may affect each eye differently. AMD is most common in the white population.
Types of macular degeneration
There are two types of macular degeneration: Dry AMD and Wet AMD.
Dry AMD (also called non-exudative AMD) is the most common form, affecting 80%-90% of AMD patients.
Dry AMD is due to an accumulation of proteins in the macula that causes the retinal cells above them to lose function. These protein deposits are called drusen. Most patients with dry AMD notice a gradual, painless loss of vision that progresses with time.
Wet AMD (also called exudative AMD) is a more visually threatening condition and accounts for 10%-20% of AMD cases.
Wet AMD is caused by leaky blood vessels in the retina. These abnormal blood vessels may leak fluids or blood into the back of the eye.
Patients with wet age-related macular degeneration typically experience more significant vision loss than those with dry AMD. The vision loss caused by wet AMD is often noticed by the patient once the condition is very serious.
In some cases, wet AMD can cause sudden vision loss.
Macular degeneration symptoms
Early signs of vision loss from AMD include shadowy areas in your central vision or unusually fuzzy or distorted vision. Some patients may notice wavy or distorted words when reading.
Additional symptoms include difficulty seeing details in poor lighting conditions and glare sensitivity.
Many patients do not notice the symptoms of AMD if they are present in only one eye or are more pronounced in one eye than the other. When viewing with both eyes simultaneously, the symptoms of blur and distortion may not be noticed.
Causes of age-related macular degeneration
Though macular degeneration is associated with aging, research suggests there also may be a genetic component to the disease. Researchers have noted a strong association between the development of AMD and presence of a variant gene.
Some researchers believe that over-exposure to sunlight also may be a contributing factor in development of macular degeneration, but this theory has not been proven conclusively.
Risk factors for developing macular degeneration include:
Aging – Men and women over 50 years of age have a higher risk of developing this condition.
Sex – AMD affects more women than men. This may be due to the different inflammatory responses that occur in men and women. Women tend to have higher levels of inflammation than men, which can also contribute to depression.
Obesity and inactivity – Eating a diet that is high in saturated fat can contribute to obesity and increase your risks for AMD.
Heredity – Having a sibling or parent with AMD means that your chances to develop the condition are tripled when compared to someone without a genetic predisposition.
Cardiovascular disease – Heart disease can damage the blood vessels of the eyes and contribute to AMD. High blood pressure can also play a role.
Smoking – Smoking cigarettes and using tobacco products may double your risk of developing AMD.
Past sunlight exposure – People with a history of more sunlight exposure seem to be at higher risk.
The American Academy of Ophthalmology (AAO) notes that findings regarding AMD and risk factors have been contradictory, depending on the study. The only risk factors consistently found in studies to be associated with AMD are aging and smoking.
Complications from AMD
The main complication of age-related macular degeneration is central vision loss. Central vision gradually decreases, leaving only side (peripheral) vision. This can make normal activities like reading, driving and distinguishing images difficult. People with severe or late-stage AMD could be considered legally blind.
Some other complications that can arise from AMD are mental health issues like depression and anxiety.
How is macular degeneration diagnosed?
The early stages of AMD do not usually cause any noticeable symptoms. This could lead to a later stage diagnosis, which may be more difficult to treat. In order to catch AMD as soon as possible, it’s important to see an eye doctor once a year for a comprehensive eye exam.
An ophthalmologist or optometrist may use any of the following diagnostics to detect age-related macular degeneration:
Visual acuity test – A visual acuity test, or vision field test, is a common diagnostic given during routine eye exams. It is used to measure the strength of your vision at various distances and incorporates the amsler grid to test your ability to see straight lines.
Dilated eye exam – A dilated eye exam involves dilating the pupils so your doctor can get a clearer view of the retina.
Fluorescein angiography – A yellow dye called fluorescein is injected into the arm. As the dye travels through the bloodstream, images are taken of the eye to see if any leaks are present in the macula.
Optical coherence tomography (OCT) or optical coherence tomography angiography (OCTA) – The OCT device takes images of the back of the eye as you look into the machine. OCTA differs slightly in that it uses laser light reflection as well as the OCT device to examine leaks.
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Treatments for macular degeneration
There is no cure for macular degeneration, but some treatments may delay its progression or even improve vision.
Treatments for macular degeneration depend on whether the disease is in its early-stage dry form or in the more advanced wet form.
For dry AMD, there are no FDA-approved treatments, but nutritional supplements containing antioxidant vitamins can reduce the risk of dry AMD progressing to sight-threatening wet AMD.
For wet AMD, the goal of most treatments is to shrink or stop abnormal blood vessel growth and prevent the leakage of fluid into the retina. The first line of treatment is the injection of a medication (Avastin, Lucentis or Eylea) directly into the affected eye. Additional medical and laser procedures are also available to treat wet AMD.
Another technique that is performed for wet type AMD is laser photocoagulation. This treatment uses an intense light beam to seal leaking blood vessels. First, the eye is numbed with anesthetic eye drops. The laser is then focused onto the macula.
Laser therapy for age-related macular degeneration can result in a new area of vision loss. However, this result is preferred over leaving AMD untreated since AMD can cause further vision loss.
Photodynamic therapy is a treatment for wet type AMD that combines laser technology and special medication (Visudyne) that is injected into the arm.
After the injection, an eye doctor will administer anesthetic eye drops and focus the laser onto the eye. When exposed to the laser’s light, the medicine creates blood clots in the abnormal macular blood vessels to seal them off.
For AMD patients who have suffered any degree of vision loss, low vision devices such as magnifiers, telescopes and apps on digital devices can help to maximize vision potential. Large-print products are also available for accessibility. Low vision aids contribute to quality of life improvements for people with long-term vision loss.
Macular degeneration prevention
A person’s risk for developing AMD goes up when they smoke, eat an unhealthy diet and live a sedentary lifestyle. To combat these risks, the best way to reduce the chances of developing AMD is to live a healthy lifestyle. This includes:
Eating a balanced diet
Staying active and exercising
Keeping your blood pressure and cholesterol under control
Quitting smoking cigarettes and other tobacco products
Wearing sunglasses to protect your eyes from UV rays
When to see an eye doctor
If you notice sudden or gradual changes in your central vision, see your eye doctor to rule out macular degeneration as the cause. Yearly, comprehensive eye examinations are recommended as preventative care, especially for those 65 and older.
Eye doctors can detect early signs of macular degeneration before patients experience symptoms. Your eye doctor will likely dilate your eyes to evaluate the retina/macula. Your eye doctor also may use imaging tools to observe any retinal changes.
If you are an AMD patient who has suffered vision loss, schedule an examination with an eye care practitioner specializing in low vision rehabilitation. These vision care specialists will evaluate your vision and your daily needs to maximize function.
As you grow older, see an eye doctor regularly, as comprehensive eye exams play an important role in AMD prevention.
WHEN WAS YOUR LAST EYE EXAM? Find an eye doctor near you and schedule a comprehensive eye exam.
Hayley Foster also contributed to this article.
Age-related macular degeneration (AMD). John Hopkins Medicine. Accessed March 2022.
Is age-related macular degeneration hereditary? Icon Eyecare. February 2019.
Why do more women than men have AMD? Prevent Blindness. May 2019.
Laser photocoagulation for age-related macular degeneration. John Hopkins Medicine. Accessed March 2022.
Photodynamic therapy for age-related macular degeneration. John Hopkins Medicine. Accessed March 2022.
Low vision aids. Macular Society. Accessed March 2022.
Age-related macular degeneration. Cleveland Clinic. December 2020.
Page published on Friday, March 1, 2019
Page updated on Tuesday, June 14, 2022
Medically reviewed on Saturday, April 2, 2022