Age-Related Macular Degeneration (AMD)

There are two primary types of AMD:

• Dry AMD is the more common type, making up about 75%–80% cases represent the dry form. Genetic and environmental factors are thought to cause dry AMD although an exact cause has not yet been identified. The loss of vision is usually slow and gradual. Most patients experience near-normal vision or only slight vision loss. The ageing-induced deterioration of an important support membrane under the retina has been theorised to cause dry AMD.

• Wet AMD is less common type of AMD, it is the most common cause of severe vision loss. Wet AMD occurs when abnormal blood vessels grow under the retina. This causes a leakage of fluid and blood, which prevents the light-sensitive cells in the retina from functioning properly. As the condition does not affect peripheral (side) vision, complete vision loss is unlikely. 

  Geographic atrophy, a less common form of wet AMD, represents a condition involving the severe thinning or loss of the macula. However, there is an absence of leaking blood vessels. Antiangiogenic medicines are not effective against geographic atrophy.

AMD gradually impairs the visual precision required for daily activities. Symptoms include:

• Blurring of central vision while peripheral vision remains normal
• Difficulty recognising faces
• Trouble reading, driving, or performing tasks requiring fine details (such as telling the time or seeing a bus number), or reading

The exact causes of AMD are unknown. However, several risk factors have been identified:

• Ageing
• Smokers
• Overweight or obesity and subjects with
• Hypertension
• Family history of AMD
• Both genetic and environmental factors contribute to the development. 

AMD is diagnosed by an ophthalmologist through clinical examination and confirmed with additional tests:

• Retinal scan to evaluate AMD severity.
• Optical coherence tomography (OCT) of the macula, a non-invasive imaging test that uses light waves to capture cross-section images of the retina.
   

Treatment options for AMD include:

• Dry AMD has no available treatment options.
• Wet AMD is treated by injecting anti-vascular endothelial growth factor (VEGF) drugs, also known as anti-angiogenic medicines, into the eye. These prevent the growth and leakage of abnormal blood vessels within the retina, and eventually, retinal bleeding. Generally, repeated injections are required several times per year to control wet AMD.

Medical attention is advised if you:

• Notice blurring of central vision.
• Have difficulty reading, driving, or recognising faces.
• See a sudden dark or empty spot in your vision.
• Experience any rapid change in visual clarity.

Early evaluation improves the chance of preserving eyesight.

Preventive measures for AMD include:

• Quitting smoking
• Maintaining a healthy weight through a well-balanced diet
• Following a healthy lifestyle, including regular exercise regimens
• Controlling blood pressure
• Certain antioxidant-based and zinc-based supplements may halt the progression of AMD although their benefits have not been proven

Regular comprehensive eye exams, even when there are no changes in vision, are advised for the early detection of AMD before major vision loss. Timely detection and treatment are crucial to counter the vision impairment resulting from the progression of AMD.

An ophthalmologist, particularly one specialising in retinal diseases, should be consulted for diagnosis, monitoring, and treatment of AMD.