As we start to live longer health conditions due to aging have started to increase. One of these is macular degeneration, which is the leading cause of blindness in New Zealand, affecting 1 in 7 people. Considering its huge impact on the population very few people have heard of it, so we are going to take a look at it.
What is the macula?
Without getting too complicated light comes into the eye and is focused in the area at the back of the eye called the retina. The cells in this area convert the light into a signal that is sent through the optic nerve that goes out the back of the eye to the brain. This is the first part of how we process what we see. The macula is a small area in the retina that focuses fine detail, so we have a clear, crisp image of what we are looking at.
What is Macular Degeneration?
Over time the macula can become damaged, resulting in a loss of central vision. There are two forms of macular degeneration, wet and dry. The dry form is most common and accounts for about 90% of people with macular degeneration. It is caused by thinning of the macula tissues and the build up of tissue debris on the macula. This accumulates gradually over time and results in a gradual loss of clear central vision. The wet form is caused by the growth of new blood vessels under the retina that leak blood and fluids into the area causing permanent damage to the macula. Changes to central vision occur suddenly in this type and can cause irreversible blindness.
Signs & Symptoms of Macular Degeneration?
With the gradually occurring dry form you may notice that you need more light for reading or doing detailed work (like sewing). Words may seem blurred or there are dark patches in the central vision. You may also notice fuzziness in your central vision, which makes it hard recognising faces. With the wet form straight lines may seem distorted and you may not be able to focus on a central point. Also colours may seem less bright. You can see from the picture here how it affects your vision.
Macular Degeneration diagnosis
An eye examination is used to determine if there is any damage to the macula and there are several tests that can be done. The two most common ones are as follows:
Dilated Eye examination – This is where the optician put drops in the eye to dilate (widen) the pupil, so they can see the back of the eye. With dry macular degeneration it is possible to see the yellow-white deposits that accumulate beneath the macula. They will also look at the retina and optic nerve in general.
The Amsler grid – This is a picture of a grid that you have to look at one eye at a time. You are to stare at the dot in the middle. You can see from the pictures we have included that the lines appear wavy or distorted for those people who have some degree of macular degeneration.
What causes Macular Degeneration?
The exact cause of dry macular degeneration is not known. However there is a connection with oxidative (free radical) damage of the eye tissues. There are also a number of risk factors associated with the condition. These are as follows:
- Hereditary – there is a greater likelihood of getting the condition if others in your family have had it.
- Smoking – smoking causes free radical damage and greatly increases risk
- Diabetics and obesity
- Excessive exposure to high levels of sunlight without adequate eye protection, such as those who work outside
- Hypertension and those who have atherosclerosis (deposits that build up in the arteries)
- Getting older – more common in the over 50’s
- Being white and female – this condition is more prevalent in women and in Caucasians.
What can I do to try and prevent Macular Degeneration?
- Eye protection – blue light has been shown to damage the eye, so wearing UV blocking sunglasses outdoors can help.
- Quit smoking
- Have routine eye examinations – it is recommended for over 50’s to have eye examinations, including macular tests on a regular basis. If you are diagnosed there are treatments and health changes you can make to slow down the damage
- Increase good fats and decrease bad fats – saturated fats from animal products cause inflammation and should be eaten in moderation. Also fried foods and some takeaways are high in inflammatory fats and can cause oxidative damage. Increase your omega 3 oils as they are anti-inflammatory and protect your cells from oxidative damage. These oils are found in fish, krill oil and in non animal forms like flax seed and sea buckthorn.
- Increase colourful fruits and vegetables – these are high in antioxidants that will protect the eye. Many orange and red foods, like pumpkin, carrots, oranges, capsicum and green leafy vegetables contain beta carotene. This is particularly protective of the eye.
- Manage diseases like diabetes, high blood pressure and high cholesterol.
- Lose weight if you are over weight
Macular Degeneration Treatment - Specific nutrients
The Age-Related Eye Disease Study (AREDS) is a major clinical trial sponsored by the National Eye Institute Study. Its first finding were published in 2001 and showed that high levels of antioxidants could slow the deterioration of the macular. Results from this wide scale research showed a 35% reduction in Age related Macular Degeneration (AMD) with targeted antioxidant supplements. If these were combined with a diet rich in antioxidants AMD risk could be reduced by a further 40%. Their research has continued with the AREDS 2 study, from which findings are published intermittently. Closer to home the Blue Mountains Eye Study (BMES) was the first large population-based assessment of visual impairment and common eye diseases Australian. This study identified many of the risk factor that are listed above.
In general both studies have shown the benefits of lutein and zeaxanthin (found in marigolds), that are both high in carotenoid antioxidants found in the macular. Other nutrients identified as preventative by the AREDS study are selenium, copper, zinc and vitamins C and E.