About macular degeneration
Age-related macular degeneration (AMD) is a disease of the macula, a small area in the centre of the retina at back of the eye, through which light passes to the brain. If the macula becomes damaged it can affect your ability to see fine detail properly. Colours also become less vibrant, and if left untreated AMD gradually destroys your sharp, central vision – that is, what you see directly in front of you. This can affect the things you do every day, such as driving and reading.
AMD doesn’t affect your peripheral vision – that is, what you see at the outer edges of your vision – so it doesn’t cause complete blindness. It usually (but not always) affects both eyes, and can progress at a different rate in each eye. Yet despite the fact that it’s the UK’s most common cause of vision impairment, the exact cause of AMD is still unknown.
Are you at risk?
Macular degeneration is thought to affect people over the age of 60 more than other age groups, but it can also happen when you’re younger. Age is the most significant risk factor, but there are other things that may increase your risk too, including the following:
- Smoking (according to the NHS, this is a significant risk factor for AMD, with smokers up to four times more likely to develop the condition than non-smokers).
- Gender (women are believed to have a greater risk than men).
- Ethnic background (Caucasians may be more likely to develop AMD than people with darker skin).
- Genetic susceptibility (you may have a higher risk if you have immediate family members who have AMD).
- Diet (not eating enough nutrient-rich foods, such as colourful fruit and vegetables, could increase your risk of developing AMD).
- It’s also possible that drinking more than four units of alcohol every day for a number of years could raise your risk of having early AMD.
- Sunlight is another possible risk factor, specifically exposure to lots of sunlight during your lifetime .
- Obesity – having a body mass index (BMI) of 30 or higher – is also thought to increase your chances of developing AMD.
What are the signs?
AMD doesn’t cause pain, but there are several general symptoms to look out for, including the following:
- Blurring in the centre of your vision.
- Distortion of an object’s shape, size or colour.
- Straight lines appearing wavy or fuzzy.
- Sensitivity to light.
- Seeing light, shapes and colours that aren’t there.
Remember, while AMD usually affects both eyes, it can affect just one, so check each eye separately too. Cover each eye in turn and get to know what’s normal for each eye individually. To see a simulation of how somebody sees with AMD, download the Royal National Institute of Blind People’s app from iTunes.
Types of AMD
There are two main types of macular degeneration: wet AMD and dry AMD.
Dry AMD: This is the most common and least serious type of the condition, affecting around 85 to 90 per cent of cases. It’s what happens when the light-sensitive cells in the macula slowly break down, gradually blurring the central vision in the affected eye.
The most common symptom of dry AMD is slightly blurred vision. For instance, you may have difficulty recognising faces or you may need more light for reading and other tasks. Another common early signs of dry AMD is the presence of small deposits, known as drusen, under the retina. These are most often found in people over the age of 60, and are thought to damage the light cells in the macula.
As dry AMD gets worse, you may see a blurred spot in the centre of your vision, though the loss of vision is gradual and can take a number of years.
Wet AMD: Ten to 15 per cent of people who develop macular degeneration have wet AMD, which is also referred to as neovascular AMD. This happens when abnormal blood vessels behind the retina start to grow under the macula. These new blood vessels cause swelling and bleeding beneath the macula, causing damage to the macular and, eventually, scarring.
Wet AMD can develop very quickly, which means you lose your central vision much faster than with dry AMD. The good news is that there is treatment that can stop the blood vessels from growing and damaging the macula, but it needs to be given quickly.
Does dry AMD progress into wet AMD?
An estimated one in 10 people with dry AMD go on to develop wet AMD. There is, however, no way to tell if or when dry will turn into wet AMD.
Diet and your vision
While experts still don’t know the exact cause of AMD, many believe there are steps you can take to minimise the chances of developing it. One of those steps is to eat a well-balanced diet.
Antioxidants: Certain nutrients are thought to help protect your eyes from sight-impairing diseases such as AMD, including antioxidants that may neutralise harmful substances called free radicals.
Among the antioxidants thought to help fight eye damage are lutein and zeaxanthin. Good sources of lutein and zeaxanthin are green vegetables such as kale, broccoli, green beans, peas, sprouts, cabbage, spinach and lettuce, plus fruit including kiwi, papaya and honeydew melons. Cavolonero– a variety of kale – is particularly high in lutein, containing almost twice the amount of that found in spinach and 75 times the amount found in carrots.
Other antioxidants thought to benefit eye health include lycopene (tomatoes), astaxanthin (marine algae), beta carotene (carrots, pumpkin, papaya), anthocyanidins (blackcurrants, bilberries), vitamin E (sunflower seeds, nuts, wheat germ oil) and vitamin C (red peppers, strawberries, spring greens).
Minerals: It’s also thought that certain minerals could help maintain good eye health, including zinc and selenium. Eat more seafood, nuts, Quorn, wheat germ and seeds to boost your intake of zinc; and Brazil nuts, tinned tuna, sardines, egg yolks and sunflower seeds for more selenium.
Oily Fish: According to the College of Optometrists, eating fish such as salmon, pilchards, sardines, herring and trout may also help protect your eyes against AMD.
Saturated Fats: Cutting down on the amount of saturated fat in your diet – that is, fats mostly found in animal products such as beef, lamb, pork, lard, butter, cream and cheese – may also help to reduce your risk of AMD. Check the nutrition labels on processed foods and baked goods too, as these can often be high in saturated fats.
5 ways to protect your eyes
- Wear sunglasses
Wearing sunglasses may help protect against AMD because the UVA and UVB rays in sunlight can harm your macula. Make sure your sunglasses has the correct level of protection – choose a pair that carries the CE mark or British Standard BS EN ISO 12312-1:2013.
- Have regular check-ups
Having an eye test once every two years – or as often as your optician recommends – is important because it can help spot the very early signs of AMD. Even if you can see perfectly well, there may be early damage happening that could be picked up by an eye test.
Getting treatment as early as possible is crucial, since it can make the treatment more effective and prevent any damage from getting worse.
Currently, a two-yearly eye test is recommended for most people. However, if you are aged 40 or older and in an at-risk group for an eye condition (if you have a family history of eye conditions, for instance) you should have an eye test at least every two years.
- Give up smoking
Smokers are more likely to lose their sight than non-smokers, with smoking linked to an increased risk for AMD (according to the RNHS, smokers are four times more likely to develop it than people who have never smoked.). That’s because the chemicals in tobacco damage the blood vessels in the macula. And the more you smoke – and the longer you smoke – the higher your risk.
The good news is giving up smoking reduces your risk over time, and 20 years after you quit your risk of developing AMD should be the same as that of a non-smoker.
- Watch your weight
Obesity increases your risk of eye health problems, including AMD. If your body mass index (BMI) is 30 or more, consider healthy ways of losing weight and maintaining a BMI of between 18.5 and 24.9, which is considered the healthy range. Remember that as well as trying to eat fewer calories than your body needs, you should also be aiming to be more physically active (150 minutes of moderate-intensity activity a week is recommended).
- Know your family history
AMD can run in families, so if yours has a history of an eye condition it’s even more important to have your eyes checked regularly and protect yourself by putting other lifestyle measures into place.
Supplementary Benefits for Eyes
Currently there is no treatment for dry AMD, but treatments that stop the growth of new blood vessels – such as injections of anti-vascular endothelial growth factor medicines –may help in the case of wet AMD if they’re given quickly enough. However, one of the ways to protect against the development of AMD may include taking certain natural supplements designed to improve eye health:
Lutein and Zeaxanthin: These belong to a group of natural plant pigments called carotenoids that are found in high concentrations in the macular as well as in the surrounding tissue of the retina. Some studies show that lutein and zeaxanthin may be promising in terms of preventing AMD (i), and that they may work by colouring the macula and thereby protecting it against the sun’s rays.
Plant Flavonoids: Other plant compounds known as flavonoids are known to support blood vessel health, including the blood vessels in the eyes. Flavonoids thought to boost eye health include anthocyanidins, which are found in dark-coloured fruits such as blueberry and bilberry, and oligomericproanthycyanidins, which are found in grape seeds. Studies suggest these substances may help prevent or treat AMD (ii).
Ginkgo Biloba: This herb also contains flavonoids and is widely used to increase circulation, including blood flow to the eyes (and in particular the optic nerve). In one study, volunteers with macular degeneration took either 60mg of ginkgo biloba a day or a higher 240mg daily dose. Both groups found their vision had improved, with those taking the higher dose reporting more significant improvements (iii).
High-Strength Multivitamin and Mineral: Taking a good-quality multivitamin and mineral supplement that contains antioxidant vitamins A, C and E and the mineral zinc may help protect against AMD. One study, which included 3,640 individuals in the early stage of AMD, suggests antioxidants combined with zinc may even slow the progression of the condition (iv). Zinc also has official backing from the EU via the European Food Safety Authority’s (EFSA’s) confirmation of a relationship between zinc and maintenance of normal vision.
Fish Oils: One of the omega-3 fatty acids found in fish oil – namely docosahexaenoic acid (DHA) – has also been approved by the EFSA as contributing to the maintenance of normal vision. It’s also thought that people who eat a diet rich in omega-3 fatty acids may have a lower risk of developing AMD, and that fish oil may support eye health in general.
References:
(i) Landrum JT, Bone RA, Kilburn MD. The macular pigment: a possible role in protection from age-related macular degeneration. AdvPharmacol. 1997;38:537-556. Hammond BR Jr, Wooten BR, Snodderly DM. Density of the human crystalline lens is related to the macular pigment carotenoids, lutein and zeaxanthin. Optom Vis Sci. 1997;74:499-504.
(ii) Scharrer A, Ober M. Anthocyanosides in the treatment of retinopathies. KlinMonatsblAugenheilkd. 1981;178:386-389. Caselli L. Clinical and electroretinographic study on activity of anthocyanosides. Arch Med Intern (Parma). 1985;37:29-35.
(iii) Fies P, Dienel A. Ginkgo extract in impaired vision—treatment with special extract EGb 761 of impaired vision due to dry senile macular degeneration. Wien Med Wochenschr. 2002;152:423-426.
