What is Age-related Macular Degeneration?
In this series of blogs posts, which are based on short interviews, Medical Retinal Expert Jaheed Khan describes the different types of AMD; including:
- the dry and the wet,
- how they present,
- what they look like,
- how they differ, and
- how we can treat them.
Jane Olver: Good Morning Jaheed. Thank you very much for agreeing to talk this morning about age-related macular degeneration for the website. Tell me, what is age-related macular degeneration?
Jaheed Khan: Age-related macular degeneration is a term used to describe a degenerative change and an ageing change within the retina at the back of our eye. It affects the central part of our retina which is called the macula, and certain characteristic appearances of the macula occur with age that happens in everyone, and we lump in age-related macular degeneration to describe those particular changes.
JO: What sort of ages are you talking about for age-related macular degeneration Jaheed?
JK: We tend to start to see early signs of ageing above the age of 65. We notice an increase in those characteristic changes through the next decade or two up until obviously the end of life, so different people are affected by different rates of ageing, but we see most of those signs above the age of 65.
JO: Jaheed, tell me about age-related macular degeneration, please?
JK: Well in two broad categories, we have dry age-related macular degeneration and wet age-related macular degeneration. They are two conditions which are similar but share features that they have different outcomes and different appearances. Dry macular degeneration refers to where the cells and worn away so have natural wear and tear of the retinal cells, and we have areas which have worn away.
JO: Is it like our skin getting a bitter thinner or patchy as we age?
JK: Correct, and the result is that the vision is affected centrally because those areas do not fire as a result of the light that falls on them.
Wet macular degeneration refers to the growth of new blood vessels underneath the retina from a layer called the choroid. Those blood vessels can push the retina up, and they can bleed into the retina and the two main differences between dry and wet AMD is the appearance as we described, but also the progression of the disease. The dry macular degeneration tends to be slow and progressive. Unfortunately, the wet type tends to be quick and degenerative and sight-threatening.
JO: So what is the proportion between the two, the dry and the wet AMD?
JK: The large majority of us will eventually have dry age-related macular degeneration, and it is only the minority that has wet. Depending on the risk factors and the age groups we are looking at, there is a sort of 10% conversion rate per year. But we cannot predict that. We rely on people´s symptoms to dictate whether they have developed wet macular degeneration.
JO: Thank you. In the next interview with Medical Retinal Expert Jaheed Khan, we will talk more about the treatment of wet AMD.