Patient Guide

Age-Related Macular Degeneration (AMD)

What is the macula?

The inside of the eye is lined at the back by a layer of delicate nerve tissue called the retina. The retina is like the film of a camera and converts the light into images, and sends them to the brain. The macular is a small area at the very center of the retina which is used to see fine details for activities such as reading and sewing.

What is Age-Related Macular Degeneration (AMD)?

Wear and tear of the macula can happen with age. This causes the delicate cells to become damaged and stop working. Central vision is affected such that a dark patch blocks the center of the visual field. However, AMD almost never leads to blindness. Patients with macular degeneration will have enough side (of peripheral) vision to get around and keep their independence. AMD is the leading cause of legal blindness in the over-65-year age group in developed countries of the west. Some patients developAMD even before they reach the age of 60. As the population in Singapore is ageing, it is becoming a significant cause of blindness here as well.

Types of AMD

DRY AMD

In this type, there is there is deposition of waste products in the macular region, followed by degeneration (wear and tear) of the retinal cells. Although there is no known effective treatment for dryAMD, loss of vision is usually not severe until very advanced stages. This form ofAMD is more common than the wet form.

WET OR EXUDATIVE AMD

The development of abnormal vessels (known as choroidal neovascularization) under the retina can lead to fluid and protein leakage or bleeding. The loss of vision is usually more severe. There are various forms of treatment available for wetAMD. Despite treatment, wetAMD often leads to severe loss of vision. Another form of wetAMD which particularly affects Asian is idiopathic polypoidal choroidal vasculopathy.

What are the symptoms?

In the early stages, central vision of the eye may be blurred or distorted, with objects looking an unusual size or shape and straight lines appearing wavy or fuzzy. This may happen quickly or develop over several months.

Because macular degeneration affects the centre of the retina, people with advancedAMD will often notice a blank patch or dark spot in the centre of their sight. This makes reading, writing and recognising small objects or faces very difficult.

What treatments are available?

If theAMD is detected late in its progression, such as when severe scarring at the macula has already developed, vision is unlikely to recover.

Management of the disease is then aimed at preventing further deterioration, as well as early detection and treatment of a similar disease in the other eye. In the advanced form of the disease, low vision aids such as mini-telescopes and magnifying glasses may help some patients.

IfAMD is detected early, there are better chances for treatment and there is a greater likelihood of improving vision or slowing the deterioration, depending on the form of the disease.

The types of treatment available forAMD include:

  • Observation with regular check-ups for mild and non-progressive forms of the disease.
  • Destruction of the abnormal new vessels in wet AMD using:
    • direct laser ablation
    • transpupillary thermotherapy (TTT)
    • photodynamic therapy (PDT
  • Injections inside or around the eye can be used to reverse the development of abnormal new vessels and control inflammation. The type of medications used include:
    • Anti-angiogenesis drugs (Macugen, Lucentis, Avastin)
    • Steroids (Anecortave, Triamcinolone Acetonide)
  • Surgery can be performed to clear the blood from under the macula using an injection of a drug (tissue plasminogen activator) and gas into the eye to move the blood away from the macula.
  • Nutritional supplements containing selenium, zinc, Vitamin A, C and E may help patients at risk of AMD.

However, such supplements in high doses can have side effects and you should consult your doctor before beginning long-term supplement taking.

What should I do if I think I have macular degeneration?

Anyone who develops blurring of central vision should be examined by a retinal specialist (an eye doctor specialised in retinal diseases) as soon as possible. Tests may be required to help in diagnosis and assessment of the condition. Treatment will be based on findings of the examination and investigations. Your retinal specialist will be the best person to explain the problem and the treatment options.