Age-related macular degeneration (AMD) is a condition that causes progressive vision loss. Dry AMD is a subtype, and it typically progresses more slowly than wet AMD.
The cause of dry AMD is damage to the light-sensitive cells on the macula, which is part of the retina at the back of the eye. This damage prevents the brain from understanding visual information, leading to a loss of central vision.
This article explores what dry AMD is, its symptoms, causes, and treatment.
Dry AMD is a disease of the macula, which is the part of the eye that sits near the center of the retina. This part of the eye allows for high resolution color vision. However, in dry AMD, the macula’s light-sensitive cells die, making it difficult to see clearly.
Often, blurry vision is the first sign of AMD. Eventually, a person experiences loss in their central field of vision. With dry AMD, these changes usually occur slowly. With wet AMD, leaky blood vessels develop under the macula, which speeds up the damage.
Regular and comprehensive eye exams can detect macular degeneration before it causes vision changes. With appropriate treatment, doctors can slow vision loss.
Doctors divide dry AMD into three stages: early, intermediate, and late. Each stage comes with different symptoms.
In the early stage, a person
At the late stage, people can have a variety of symptoms, including:
- one or more blurred or blank areas toward the center of their vision, which increase over time
- straight lines appearing wavy or wonky
- colors appearing less bright
If an individual notices that straight lines appear wavy, they should seek urgent medical attention from an eye doctor, as this is a warning sign of late AMD.
Doctors do not fully understand the causes of AMD, but they know that individuals
- Smoke: People who smoke are 2–5 times more likely to develop AMD. As the retina and macula consume large amounts of oxygen, anything that interferes with oxygen delivery, such as smoking, may affect eye health.
- Have high blood pressure: Similarly, having high blood pressure can restrict blood flow to the eye and reduce its oxygen supply. This may raise the risk of developing the condition.
- Have a family history of AMD: If someone has a relative in their immediate family with AMD, they are more at risk. Researchers have found several genes that link with macular degeneration risk.
- Have obesity: Individuals with a body mass index (BMI) over 30 are 2.5 times more likely to develop AMD.
- Have an unbalanced diet: If a person consumes high amounts of fat, cholesterol, and refined carbohydrates, and low amounts of leafy green vegetables or antioxidants, they may be more likely to develop AMD.
- Spend time in the sun: Some studies suggest that prolonged exposure to UV light may damage the retina, increasing the risk of AMD. However, evidence on this is not conclusive.
- Are white: White people have a higher risk of AMD compared with people of other racial groups, potentially due to eye pigmentation. Light-colored eyes are more likely to develop dry AMD, possibly because they provide less protection against UV light.
- Are female: Females more likely than males to develop AMD. This could be because females live longer, on average, so they have more time to develop the disease.
To diagnose AMD, an ophthalmologist performs a comprehensive eye exam, including:
- Eye chart test: This test measures a person’s sight from various distances.
- Autofluorescence: A doctor may use autofluorescence photos to examine the retina and measure disease progression in those with advanced dry AMD. Autofluorescence allows doctors to monitor the retinal pigment epithelium, which is the deepest layer of the retina.
- Dilated eye exam: During this test, a doctor uses special eye drops to dilate the pupils, allowing them to examine the retina for disease and see any optic nerve damage.
- Fundoscopy or ophthalmoscopy: These tests involve the doctor shining a beam of bright light into the dilated eye to check for problems in the retina, the blood vessels, the area where the optic nerve connects to the retina, and the choroid, which is a thin layer of tissue connecting blood vessels and nerves to other parts of the eye.
- Fundus photography: The doctor may use a specialized camera to photograph the back of the eye and help them find signs of disease. It allows the doctor to measure changes in the eyes between visits.
- Optical coherence tomography (OCT): This noninvasive technique captures cross-sectional images of the retina, allowing the doctor to measure the thickness. OCT helps doctors identify regions that are thinning and can also assess treatment responses.
Doctors can detect the signs of AMD during a regular eye test. People can also see an ophthalmologist if they notice any changes in their vision.
There is no cure for AMD, but treatment can slow the progression of the disease. It is important to begin treatment as early as possible, as once AMD reaches the advanced stage, a doctor cannot prevent further vision impairment.
Early treatment for dry AMD involves making lifestyle changes to reduce damage to the retina and monitoring for sight changes that could indicate progression of the disease. Early treatment may involve:
- quitting smoking
- adopting a balanced diet, high in antioxidants
- getting regular exercise
- controlling high blood pressure
- scheduling regular appointments with an ophthalmologist
A doctor may recommend that the individual use an Amsler grid at home. This is a tool that can help people tell if their symptoms are changing. If AMD is progressing, the lines of the grid will start to curve.
For intermediate dry AMD, the main treatment is a special dietary supplement known as the Age-Related Eye Disease Studies 2 (AREDS2). AREDS2 may be able to
AREDS2 contains high amounts of antioxidants, vitamins, zinc, and copper. Due to this, it can cause side effects or interact with existing drugs or conditions a person has. A doctor can talk through whether AREDS2 is right for someone.
An option for late-stage dry AMD is an implantable miniature telescope (IMT). This involves surgeons placing a tiny telescope into one eye. The eye with the IMT then provides central vision, while the other provides peripheral vision. People who undergo this procedure need training to learn how to use the device.
In addition to treatments that target AMD itself, people with the condition sometimes have to adapt to changes in their vision, such as blurriness. The
The type of vision changes AMD causes can make it difficult to read, drive, and distinguish colors. However, there are ways to make tasks easier. People with minor vision loss may find it helpful to try:
- using brighter lights
- reading using a magnifying glass
- wearing anti-glare sunglasses
Vision rehabilitation is a type of support people with more advanced vision loss can receive. It helps people learn how to live with the changes in their sight, such as by adapting their home or using visual aids. Ask an ophthalmologist about this type of support.
People can find resources on adjusting to vision loss on the American Foundation for the Blind website.
In around 10–15% of people with dry AMD, the condition progresses to the wet form. Wet AMD is more serious and can lead to severe vision loss, as the symptoms appear and worsen rapidly.
In addition to nutritional supplements, doctors have other treatment options to prevent further vision loss in wet AMD. These include drugs that a doctor can inject into the eye and photodynamic therapy, which is a form of laser treatment.
Dry AMD is a progressive disease that occurs when light-sensitive cells on the macula begin to die. Unfortunately, there is no cure, but early detection and treatment can delay vision loss. With treatment, the condition may stop progressing once it reaches the intermediate stage for some people.
Frequent eye checkups and monitoring are essential in managing dry AMD. It can also help to get support with adapting to visual changes, such as blurriness or loss of central vision. Speak with an ophthalmologist about any concerns.