What Causes Macular Degeneration?
Macular degeneration is the most common cause of vision loss in Americans over 60. Although it does not cause complete blindness, it can make everyday tasks like reading and driving difficult.
So, what causes macular degeneration, and can it be prevented? Here’s all you need to know.
What is Macular Degeneration?
Macular degeneration, sometimes known as age-related macular degeneration (AMD), is a common eye disease.
It affects part of the eye called the macula, which is responsible for providing clarity in the central area of vision.
AMD can cause vision loss in the direct line of sight, making it challenging to drive, read, watch TV, or recognize faces. However, it does not affect the peripheral vision and does not cause complete blindness.
As the name suggests, it is more common in older people, especially those over the age of 60.
What Causes Macular Degeneration?
There are two types of macular degeneration, wet and dry.
Dry macular degeneration is the most common type and accounts for around 80% of cases. It occurs when the macula becomes thin and covered in yellow protein deposits called drusen. Dry AMD leads to gradual vision loss, usually over the course of several years.
Wet macular degeneration, also known as neovascular AMD, is less widespread. It is the result of new blood vessels forming under the retina, the tissue at the back of the eye. These blood vessels are weak and prone to bleeding, which leads to vision loss. Wet AMD can damage the vision far more rapidly than dry AMD, sometimes in just a few weeks or months.
Risk Factors for Macular Degeneration
Although eye experts understand the difference between the two types of macular degeneration, their exact cause is still unknown. However, there are several factors that may increase the risk of developing AMD. They include:
- Advanced age
- Family history
- Being Caucasian
- Being overweight
- Having high blood pressure
- Having a diet high in saturated fat
Macular Degeneration Symptoms
In its early stages, macular degeneration may not cause any symptoms. This is why it is important to attend regular eye examinations. Ophthalmologists can detect early macular degeneration as part of a routine check-up.
In its latter stages, AMD can cause the following symptoms:
- Blurring or distortion in the central area of vision
- Straight lines appearing crooked or curved
- Objects appearing smaller than they really are
- Colors seeming less bright than usual
- Needing brighter light to perform activities such as reading
- Difficulty reading words or recognizing faces
Macular degeneration can affect one eye or both. In some cases, it affects one eye first before progressing to the other.
The condition is not painful and it does not alter the appearance of the eyes.
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Diagnosing Macular Degeneration
During an eye exam, an ophthalmologist will use a magnifying glass to view the back of the eye and look for abnormal blood vessels or drusen. They might use eye drops to widen the pupil, and this can cause blurred vision for several hours after the exam. In this situation, it is essential not to drive until the vision returns to normal.
Other diagnostic tests include looking at an image called an Amsler grid. It helps ophthalmologists to identify any blurry or blank spots in the field of vision.
Patients might also undergo imaging techniques, including fluorescein angiography or optical coherence tomography, which allow ophthalmologists to observe the inner eye.
Fluorescein angiography involves injecting a dye into the patient’s arm and observing how it moves through the eyes’ blood vessels. This process can highlight any changes or abnormalities in the blood flow.
Optical coherence tomography uses a special type of light to produce a detailed picture of the retina. It can help to identify thick or thin areas, and retinal swelling due to leaky vessels.
Treatment Options for Macular Degeneration
There is no specific treatment for dry AMD. Therefore, patients may have to rely on vision aids to perform everyday activities. Some of the options currently available include:
- Magnifying lenses
- Installing brighter lights in the home
- Software or applications to facilitate computer and smartphone use
- Visual training techniques, such as eccentric viewing training
Wet AMD can be treated with regular injections of anti-VEGF medication. These drugs stop the formation of new blood vessels on the retina. They prevent the condition from worsening in 90% of patients and may even improve vision in 30%.
Side effects of anti-VEGF injections include:
- Eye irritation
- A sensation of something stuck in the eye
Another option is photodynamic therapy, in which a bright laser is shone into the eye. Side effects include temporary visual disturbances and increased sensitivity to light.
Finally, it may be possible to prevent macular degeneration or slow its progression by making some healthy lifestyle changes. They include:
- Not smoking
- Maintaining a healthy body weight
- Exercising regularly
- Eating a healthy balanced diet, specifically: reducing saturated fats (butter, cheese, baked goods, fatty cuts of meat, etc.), and increasing intake of fish, yellow fruit and vegetables, and dark, leafy greens
There is also evidence that dietary supplements may help some people with AMD. The American Academy of Ophthalmology recommends taking the following vitamins and minerals daily:
- Vitamin C (500 mg)
- Vitamin E (400 IU)
- Lutein (10 mg)
- Zeaxanthin (2 mg)
- Zinc (80 mg)
- Copper (2 mg)
Beta carotene is another potentially beneficial supplement. However, smokers should not take it as it increases the risk of lung cancer. For more information, speak to a qualified ophthalmologist.