The macula is an anatomical part of the retina. The retina is the tissue lining the back of the eye, comprised of millions of photoreceptors that sense light. The macula is what is responsible for your central vision. We rely on our central vision for a lot of things – reading, writing, watching TV, recognising faces, painting, sewing, identifying colours… You name it. Basically, whenever you look at something, you’re turning your macula to receive that fine detail. So, what happens when macular degeneration sets in? Keep reading to find out about macular degeneration causes and symptoms.
What is Macular Degeneration?
The term macular degeneration typically refers to an eye disease of older age. The full name is age-related macular degeneration. As the name suggests, age-related macular degeneration:
- Affects older adults; typically, ages over 50 years are considered a risk factor
- Results in damage and degeneration of the light-sensitive photoreceptors
- Involves the macula; this means that it is very rare that macular degeneration causes complete blindness. Your peripheral vision remains unaffected, but you may experience total loss of your central vision, which may be considered legal blindness
In Australia, around 1.4 million adults have some form of age-related macular degeneration. At the moment, there is no cure for this disease, but there are effective treatments to help slow the progression of certain types of macular degeneration.
Macular degeneration symptoms can be subtle. In the early and even intermediate stages of the disease, you may not notice any changes to your sight at all. Macular degeneration symptoms can include:
- Blurry, dark, or indistinct areas around your central vision
- Seeing straight lights as wavy or distorted
- Difficulty with discerning fine detail despite glasses
- Alterations to your colour perception
- Difficulty recognising faces
- Needing brighter task lighting for seeing objects or text up close
In most cases, macular degeneration symptoms progress slowly and can just be monitored by your eye care professional. However, any sudden changes to your sight should be addressed immediately, either with your ophthalmologist or even at the emergency department of your local eye hospital. Abrupt loss of sight can indicate an aggressive form of age-related macular degeneration known as the wet or neovascular form.
Macular Degeneration Causes
Doctors and researchers are still learning more about macular degeneration causes. We do know that the basic underlying mechanism of disease is that one particular layer of the retina, known as the retinal pigment epithelium, becomes damaged from years of accumulating waste material in its cells. This collection of debris causes disruptions under this layer; these bumps are known as drusen. One of the functions of the retinal pigment epithelium is to support the metabolic demands of the overlying photoreceptor layer. If the retinal pigment epithelium is unable to do its job properly, the associated photoreceptors also deteriorate and lose their function, leading to the characteristic macular degeneration symptoms of distorted, blurry central sight.
Despite understanding this pathophysiology of age-related macular degeneration, scientists don’t fully understand why it happens in the first place, and why it might develop in some people but not others. Through extensive research, several risk factors have been identified:
- Older age; the older you are, the great your risk of developing age-related macular degeneration. The risk becomes more significant after the age of 50.
- Family history; having a relative with macular degeneration increases your risk of developing the disease as well, due to shared genetics. Those with a first-degree relative (parent or sibling), have a 50% risk of developing macular degeneration.
- Caucasian ethnicity; compared to all other races, Caucasians are at a higher likelihood of developing age-related macular degeneration.
- Smoking; tobacco smoking increases your risk of macular degeneration by 2-3 times compared to a non-smoker.
- Obesity; research has shown that being obese can increase your risk.
- Cardiovascular disease; conditions that affect your heart and blood vessels, such as hypertension, can increase your risk.
- UV exposure; the link between sunlight and age-related macular degeneration isn’t well established. However, there is some suggestion that UV exposure may play a part in developing the disease.
Is Macular Degeneration Preventable?
You may have noticed that some of the risk factors listed above can be controlled, while others are not modifiable. It is not possible to eliminate your risk of developing age-related macular degeneration entirely – unless you stop yourself from ever ageing past 50! However, based on what we know increases the risk of this blinding eye disease, doctors do have some suggestions that can help to reduce your likelihood of developing age-related macular degeneration.
- Quit smoking
- Keep yourself in good overall health, including managing (or preventing) any cardiovascular conditions and maintaining a healthy weight
- Protect your eyes from UV. Although the association between UV light and macular degeneration isn’t strong, there is no harm in wearing sunglasses and a hat when outdoors, so many doctors continue to recommend this
The role of diet in age-related macular degeneration has also been recognised as important. Specifically, maintaining a healthy intake of antioxidants and omega-3 has been shown to be beneficial for the macula. This includes a daily intake of dark, leafy vegetables, and fresh fruit, as well as including nuts and oily fish in your diet.
Nutritional supplements are also available to boost macular health, particularly those based on a study known as AREDS2. However, the benefit of these supplements has only been demonstrated in those already with age-related macular degeneration. The AREDS2 formula may help to slow the progression of dry age-related macular degeneration.
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Age-related Macular Degeneration.
Pathophysiology of age-related macular degeneration.