What is macular degeneration

Macular degeneration, or age-related macular degeneration (AMD), is a common age-related disease that affects your central vision. It is most common in people over the age of 50.

AMD doesn’t usually cause complete blindness, but loss of central vision can make it more difficult to see faces. It can also make it hard to do certain activities like driving, reading, and cooking. You usually have AMD in both eyes, but it can occasionally affect just one eye.

Let’s take a closer look at what macular degeneration is, what the symptoms are, and how the condition is treated.

What is macular degeneration?

Macular degeneration, also known as AMD, is a condition that affects the part of your eye responsible for clear central vision, called the macula. It usually occurs as you get older.

The macula is the central part of the retina, the light-sensitive tissue at the back of the eye. It is responsible for your central vision and allows you to see what is directly in front of you.

There are two main types: dry AMD and wet AMD. Wet AMD always starts out as dry AMD, which then gets worse. Around 15 to 20% of people with dry AMD develop wet AMD.

Dry (atrophic) AMD

Around 90% of people with macular degeneration have dry AMD. The disease occurs when tiny yellow protein deposits, known as drusen, form under your macula. Over time, these deposits grow, causing the macula to get thinner and less effective, leading to a gradual loss of central vision. Vision loss with dry AMD is normally gradual and doesn’t usually cause complete loss of central vision.

Wet (exudative) AMD

Wet AMD is less common but more serious. It starts as dry AMD, then progresses. Wet AMD occurs when abnormal blood vessels grow under your retina and macula. These blood vessels leak blood and fluid which builds up under your macula, damaging your macula quickly and causing rapid central vision loss.

What are the three stages of macular degeneration?

Dry AMD has three stages: early, intermediate, and late (advanced).

You may not notice symptoms of AMD until the late stage of the disease, but the condition can be picked up earlier during an eye examination. Wet AMD is always at the advanced stage.

Early AMD

During this stage, changes begin to develop on your macula, but your vision isn’t affected.

Intermediate AMD

Further changes to your macula occur. You may not experience any symptoms during this stage, or you may have some mild visual changes like blurred central vision or difficulty seeing in low light.

Late (advanced) AMD

During the late stage of AMD, you may notice a blurred area in your central vision that gets larger over time. Straight lines may appear wavy or crooked and you may see blank spots. Colours may appear less bright than usual, and you may have difficulty seeing in low light.

What are the symptoms of macular degeneration?

Dry AMD often doesn’t have any symptoms in the early stages of the disease. As damage to your macula progresses, you may experience:

• Difficulty seeing in low light
• Blurred or fuzzy central vision
• Straight lines appearing curved or wavy
• Blank or dark spots in your field of vision
• Difficulty recognising familiar faces
• Difficulty performing activities such as driving, reading, and close-up work
• Changes in the way you see colours

What are the first signs of age-related macular degeneration?

Early dry AMD doesn’t normally have any symptoms, and most people are unaware that they have it. Many people don’t experience symptoms in the intermediate stage of AMD, though you may experience mild blurred central vision or difficulty seeing in low light.

The early changes to your macula can be picked up during a routine eye examination before you develop symptoms.

What causes macular degeneration?

The exact cause of AMD is unknown, but some factors may increase your risk including:

• Having a family history of AMD
• Smoking
• High blood pressure
• Being overweight or obese

What is the most common age to develop age-related macular degeneration?

AMD is rare before the age of 50, though other forms of macular degeneration can occur at a younger age.

Your risk of developing AMD increases with age, and around 1 in 100 people between the ages of 65 and 75, and 10 to 20 out of every 100 people over the age of 85, have the condition.

How long before macular degeneration causes blindness?

Dry AMD rarely causes complete blindness, though the condition may progress to a significant loss of vision. In the late stages of the disease, you may be considered legally blind and prevented from performing activities such as driving and operating machinery.

On average, progression from early to late stage AMD takes about five to ten years.

Wet AMD progresses more quickly and is more likely to cause blindness than dry AMD. Vision loss from wet AMD can occur within a few weeks or months.

Can you reverse age-related macular degeneration?

It’s not currently possible to reverse AMD, though the progression of the disease can be slowed with treatment and lifestyle changes.

How is AMD diagnosed?

AMD is often picked up during a routine eye examination before symptoms appear. It’s important to have regular eye examinations to pick up any changes early. The NHS recommends having an eye examination every 2 years for most people. You may be advised to have your eyes examined more frequently if you have certain health conditions or problems with your eyes.

Your consultant may perform the following tests to diagnose macular degeneration.

Dilated eye exam

Before your dilated eye exam, you will be given eyedrops to dilate (widen) your pupils. Your consultant will then use a special lens to look inside your eyes and examine your macula.

Amsler grid test

The Amsler grid is a visual test used to diagnose AMD. It consists of a grid made of straight lines with a large dot in the centre. During the test, your consultant will ask you to look at the grid and identify any areas that appear blurred, distorted, or wavy, as well as any blank spots. You can also use the Amsler grid at home to monitor your AMD.

Fluorescein angiography

This test examines the blood vessels in your retina and checks for any leakage of fluid. After using eye drops to dilate your pupils, a contrast dye called fluorescein is injected into a vein in your arm. The dye is then tracked and photographed as it travels through the blood vessels in your retina. 

Optical coherence tomography (OCT)

This is a non-invasive procedure, where an imaging machine takes detailed pictures of your retina and macula.

Optical coherence tomography angiography (OCTA)

This non-invasive procedure uses laser light reflection to produce 3D images of the blood flow through your eye.

What treatments are available for AMD?

Treatment for dry AMD

Currently, there's no specific treatment to reverse dry AMD. However, a study by the National Eye Institute found that certain nutritional supplements may slow the progression of AMD, though more research is needed. The supplements may not be suitable for everyone, so it’s important to speak to your consultant before taking any supplements for AMD.

There are many things you can do to help manage your AMD. These include visual aids like magnifying glasses, using brighter lighting in your home, and apps you can install on your computer or phone. When you are diagnosed with AMD, specially trained staff will be available to help you manage the condition.

Treatment for wet AMD

There are two treatments currently available for wet AMD. Treatment should be started as soon as possible and helps to slow the progression of wet AMD in most people.

Anti-VEGF medicines

Vascular Endothelial Growth Factor (VEGF) is a substance produced by the body that helps develop healthy blood vessels.

In AMD, too much VEGF is produced, causing an overgrowth of abnormal blood vessels at the back of the eye.

Anti-VEGF injections are given directly into the eye under local anaesthetic. They work by blocking the production of VEGF and stopping the growth of abnormal blood vessels. Treatment with injections stops vision from getting worse in around nine out of ten people. Around three out of ten people see an improvement in their vision after treatment.

Anti-VEGF injections are usually given every one, two, or three months for as long as necessary.

Photodynamic therapy (PDT)

This is a less common treatment for AMD and may be used in combination with eye injections if the injections alone haven’t worked.

PDT involves having a light-sensitive drug injected into your arm. The drug travels to your eye and a laser is then used to activate the drug and destroy the abnormal blood vessels that cause wet AMD.

Most people need two to five sessions of photodynamic therapy. This treatment is only suitable for people with specific patterns of retinal damage and is not appropriate for everyone. It also carries a higher risk than treatment with injections.

Can macular degeneration be prevented?

Macular degeneration is linked to an unhealthy lifestyle. The best way to prevent or slow the progression of dry AMD is by adopting healthy habits as early as possible. Some things you can do to prevent or slow your AMD include:

• Stop smoking or never start
• Eat a balanced diet with lots of eye healthy foods like dark leafy greens, yellow fruits and vegetables, and fish
• Take regular exercise
• Lose weight or maintain a healthy weight

Conclusion

Macular degeneration is a common age related disease that causes loss of central vision and can have a significant impact on your life. Fortunately, lifestyle changes can help slow the progression of dry AMD and treatments are available to slow or stop the progression of wet AMD.

For both types of macular degeneration, early diagnosis is crucial for detecting changes in your eyes before symptoms become apparent. Early diagnosis through regular eye examinations allows you to make the necessary lifestyle changes or start treatments to slow the disease progression and the resulting vision loss.