What’s the difference between wet and dry age-related macular degeneration?
Even though there is no cure, it’s important to know about Age-Related Macular Degeneration (AMD) because it affects more than 1.8 million Americans and is the leading cause of vision loss in the U.S. The disease affects more people than cataracts and glaucoma combined. Vision loss caused by the disease is not noticed until the late stages, so regular comprehensive eye checks are essential to protect eye health. Early detection can lead to early treatment that may slow the progression of the disease. Here is what you need to know about age-related macular degeneration and its two types, wet and dry.
Macular degeneration deteriorates the retina which is the camera of the eye. AMD impacts the central part of the retina, called the macula, that focuses central vision. The macula is the part of the eye that controls reading, driving, seeing faces and the fine detail of any type of object. When it deteriorates, images can’t be received correctly. Specifically, the disease affects the inside back laver of the retina, the part that records images we see and transmits them along the optic nerve to the brain for translation.
Macular degeneration is a progressive disease. In the early stages the individual will not detect any vision loss. However, as the disease progresses it may cause wavy, blurred or lost vision. In the advanced stages it may cause people to be legally blind. Those who suffer from AMD may begin to see blind spots, grayness and other distortions in the center frame of vision. Vision remains around the edges of the central field of vision – called peripheral vision. However, it is not as clear as central vision and can make it difficult to decipher what one is seeing.
Two Types of Macular Degeneration
There are two types of macular degeneration, called “dry” and “wet”. The majority of the cases of AMD, 85 to 90 percent, are dry. The remaining cases are wet AMD.
Dry macular degeneration is a type of the disease in which blood vessels in the eye do not leak. In most cases it affects both eyes. Dry AMD gets progressively worse over the years. In dry AMD there are minimal symptoms in the early stages, with vision loss occurring in the mid to late stages. Sometimes only one eye is affected. In these cases, people tend to notice vision changes sooner as one eye begins to compensate for vision loss in the other.
Wet AMD is a more advanced form of the disease and causes vision loss when abnormal blood vessels grow in the eye. Wet AMD occurs when the blood vessels leak below the center part of the retina, the macular. The leaking and bleeding causes permanent vision loss. In some cases, the individual had dry AMD that progressed to wet AMD.
(Stargardt’s disease is considered juvenile macular degeneration, a separate disease.)
The three stages of AMD
Age related macular degeneration has three distinct stages. They are:
- Early AMD: Individuals do not experience vision loss in the early stages of the disease. However, the symptoms may be detected by a comprehensive eye exam. The ophthalmologist may detect yellow deposits beneath the retina. Early detection is important so that treatments that may slow the progression of the disease can begin.
- Intermediate AMD: In the mid-stages of AMD there may be some vision loss but not enough to alarm the individual. A comprehensive eye exam may detect changes in the retina.
- Late stage AMD: In the late stages of the disease, people begin to experience central vision loss.
It’s not known what causes wet or dry AMD, though researchers believe it may be heredity and environmental factors. They are conducting studies to determine why the cells of the retina begin to deteriorate and potential causes.
Although scientists are not certain of the causes of AMD, they do know that certain risk factors increase your chances of getting the disease. Age is the biggest risk factor as most cases of the disease occur in people over the age of 55.
According to the American Macular Degeneration Foundation, Other risk factors include:
- Genetics – People with a family history of AMD are at a higher risk.
- Race – Caucasians are more likely to develop the disease than African-Americans or Hispanics/Latinos.
- Smoking – Smoking doubles the risk of AMD.
Treatments for AMD are improving, and we covered them in our blog.
We provide vision enhancing technologies to people living with low vision caused by a variety of eye diseases, including AMD. We believe that no one should be told nothing more can be done to improve their vision. We enhance low vision and legal blindness with innovative medical devices every day. If you or a loved one are living with low vision, call us. We can help.