Types and Stages of AMD

Stages of AMD:

AMD is classified into early, intermediate and advanced stages, depending on the size and number of drusen and the amount of vision loss. AMD is also divided into wet AMD (bleeding into the retina) and dry AMD (no bleeding into the retina). Early and intermediate stages are always dry, and advanced AMD may be dry or wet.

One of the first signs of AMD is the development of drusen. Drusen are deposits in the macula. These deposits are thought to be metabolic by-products containing proteins and fats. In early AMD, drusen are usually small and scattered (see figure 1). At this stage, AMD may have little or no impact on vision. One in five people with early or intermediate AMD will progress to vision loss from Advanced AMD.

Figure 1a:
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Figure 1b:
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Figure 1c:
Early AMD Symptoms

Over time, more drusen form and the macula becomes damaged. At this stage, AMD may cause blurred vision, especially in the centre of the eye. As AMD progresses to an advanced stage (one in five cases), the area of blurred vision increases in size and eventually central vision is lost (see figure 2). About 10% of people with AMD experience the most severe form of the disease involving leakage of the retinal blood vessels into the retina. This form of advanced AMD is known as ’Wet’ AMD.

Figure 2a:
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Figure 2b:
Advanced AMD Symptoms

Forms of AMD:

There are two forms of AMD – “dry” and “wet.”

Dry AMD is characterized by the accumulation of cellular debris in the macula. This eventually leads to damage in the light sensitive cells, resulting in distortion of central vision. Although this form of AMD progresses fairly slowly for most patients, there are still treatment options that may delay and possibly prevent dry AMD from advancing to a point where severe vision loss occurs. Vision loss from advanced ‘Dry’ AMD is not reversible. One of these options is nutritional supplementation in the form of very specific high-dose vitamin therapy (AREDS).

In ’Wet’ AMD, tiny blood vessels in the macula spontaneously begin to leak blood and other fluids into the macula, destroying its ability to function properly. The wet form of AMD is more serious because it can progress very rapidly, sometimes in a matter of weeks, causing loss of vision that is not reversible.

Early Treatment:

Dry AMD: Early treatment with a vitamin / mineral complex (AREDS). A recent study has also demonstrated the efficacy of a vitamin formulation containing Vitamin B6, B12 and Folic Acid. Vitamin therapy has been shown to prevent or delay the onset of advanced AMD by as much as 6 years in a percentage of people.

Wet AMD: Treatment for wet AMD may include various drug therapies including injections in your eye (Lucentis) and/or laser surgery. Clinical Studies with Lucentis have shown that this treatment can prevent or arrest Wet AMD in up to 95% of cases. Lucentis works best when Wet AMD is caught early, before vision loss has set in. If Wet AMD is treated when visual acuity is better than 20/64, there may still be a good chance to maintain your ability to read, drive and to be independent. Once your visual acuity deteriorates to 20/100 even Lucentis may not be able to restore your ability to do those things.

Be Diligent – See your eyecare professional:

When vision loss occurs, most people do not recognise the problem and manage to get to an ophthalmologist until it is too late. This is because the vision loss that occurs, usually occurs in one eye first. The process over weeks and months allows the second eye to over compensate for the deterioration of vision. Up to 80% of people do not detect the irreversible vision loss and get a medical examination until it is too late.

If you have ‘Wet’ AMD in one eye now, Macula Risk will provide your doctor with a risk score (prognosis) for your second eye. He/She will want to insure that you are diligent with a monitoring and surveillance  program for the good eye to prevent vision loss.

AMD and Family History:

AMD is a disease that runs in families. Family history is the single most important risk factor for AMD. Having a first-degree relative (mother, father, brother, sister) with AMD significantly increases your risk of developing AMD. It also significantly increases your risk of developing advanced AMD. Because the genetic variants you inherit can come from either parent, you might have some gene variants from one parent and some from the other even if they do not have AMD. If you have early signs of AMD (drusen) then you might have inherited the disease even though neither of your parents experienced vision loss.

With recent medical advancements in genetic research there is now a way to understand how you could be affected by AMD. It is possible to examine your genetic profile to identify your risk of losing your vision from AMD. And with an understanding of your risk, you can then take preventative steps to save your sight. Inheritance cannot be predicted, but it can be determined through genetic testing.

AMD and genes:

Scientists have now identified several genes that strongly predict Advanced AMD  with vision loss—in fact, AMD is largely a genetic disease. Research including more than 100 published, peer reviewed studies at universities around the world has identified gene variations associated with AMD and the specific versions that predict vision loss due to advanced AMD. It is now possible to test for these gene variations.