What is AMD

AMD is the leading cause of irreversible blindness and today there is no effective
treatment for end stage disease.

Age-related Macular Degeneration (AMD) is the most common cause of blindness among the elderly in the industrialised world, affecting more than 35 million people in the western world alone. The frequency of the disease increases significantly with age, with more than 10% of the population over 70 years old showing signs of AMD. It presents as a progressive and debilitating loss of vision in the centre of the visual field (macula). As the disease progresses to the atrophic form, also called Geographic Atrophy, it becomes increasingly difficult for patients to recognise faces, drive, read, or perform other activities of daily life. It can also make it more difficult to see contrast and can change the way colour is seen.

What are the types of AMD?

Schematic showing a normal retina, atrophic AMD and neovascular AMD in the retina.

Photoreceptor cells
Retinal pigment epithelium
Bruch’s membrane

Normal retina image

Fluid accumulation
Displaced photoreceptor cells

Neovascular (wet) AMD retina

In neovascular AMD, blood vessels from the choroid undergo angiogenesis, resulting in abnormal blood vessel growth. Excess blood and fluid proteins leak into the retina and damage or displace photoreceptor cells, resulting in vision loss. The damage may be rapid and severe, leading to sudden and disabling loss of vision. Neovascular AMD is currently treated with frequent intraocular injections of anti VEGFs.


Atrophic (dry) AMD retina

In atrophic AMD, drusen accumulate between the retinal pigment epithelium and the choroid. As a result, photoreceptor cells in the retina can no longer receive nutrients or pass on waste to the blood vessels in the choroid and become damaged, leading to photoreceptor cell death.

There is no effective treatment today for this advanced atrophic stage, also called Geographic Atrophy.

What are the stages of AMD?

AMD is clinically classified into early, intermediate and late stages. It is possible to have AMD in one eye only, or to have one eye with a later stage of AMD than the other.

Early and intermediate AMD are characterised by:

  • thickening and loss of normal architecture of Bruch’s membrane (the innermost layer of the choroid)
  • formation of extracellular deposits composed of glycoproteins and lipids (drusen), which accumulate and spread over time in the retina.

Visual loss may be experienced by some people with intermediate AMD as drusen increase in size. However, most people will not have symptoms at this stage and the disease is often only detected during routine eye examinations.

Late stage AMD can present in two forms:

The atrophic form, also called Geographic Atrophy in which the drusen grow in size and number over time, leads to the death of photoreceptor cells in this central area (macula) responsible for the sharp central vision. This process results in a blurring or spotty loss of clear, straight-ahead vision, impairing the ability to read, drive and recognise faces. There is no approved treatment today for the atrophic form of AMD.

The neovascular form of AMD (also called wet AMD) occurs when abnormal blood vessels grow behind the macula.  The new vessels are very fragile and can leak fluid and blood leading to rapid vision loss. Neovascular AMD is currently treated with frequent intra ocular injections of anti VEGFs.

AMD and quality of life

Developing AMD can be devastating to those who were independent and active prior to the onset of this disease. Their visual world gradually diminishes into a vague blur, making ordinary daily activities challenging as the loss of central vision appearing in the late stage of the disease can interfere with simple everyday activities, such as the ability to see faces, drive, read, write, or do close work, such as cooking or fixing things around the house. Research into the quality of life of people with AMD has shown that for late-stage AMD, between 50 and 60% decrease in quality of life is reported, more than that of dialysis and similar to that encountered with stroke or prostate cancer.

Quality of life impairment is often significantly greater when rated by patients than when estimated by treating ophthalmologists for the same condition.

According to the Office of National Statistics, over 3.8 million people are affected by AMD in the UK.

Find out more

Royal National Institute for the Blind: https://www.rnib.org.uk/eye-health-eye-conditions-z-eye-conditions/age-related-macular-degeneration-amd

Macular Society: https://www.macularsociety.org