Although almost 90 per cent of people say that sight is the sense they most fear losing, most of us are not aware that there are active steps we can take to reduce the risk of sight loss.
There are steps and lifestyle practices we can take to safeguard our sight
Smoking is the number one threat to your eye health
A direct causal link between smoking and blindness has been well established. Smoking is a contributory factor to eye diseases. In fact
Smoking causes age-related macular degeneration (AMD) and cataracts, and this is due to the oxidative stress caused by smoking to retina and lens of the eye, respectively.
Smoking may lead to development or progression of AMD via oxidative damage mechanisms that lead to reduced blood flow in the eye, increased formation of abnormal blood vessels and reduced levels of lutein and zeaxanthin. This all may lead to development or progression of AMD.
Tobacco smoke contains heavy metals that can that can accumulate in the lens and because heavy metals are toxic they may contribute to cataract formation. While cataract is treatable, still it is a main cause of vision impairment in Canada.
Unfortunately, treatment options are limited for dry AMD and smokers not only double their risk of developing AMD, they also tend to develop it earlier than non-smokers.
We also know that second hand smoking (passive smoking) is almost as dangerous. Exposure to passive smoking for over a period of five years almost double the risk of developing AMD.
Smokers increase the risk of sight loss in themselves, and also in those around them. And the more they smoke the higher the risk.
Remember that if you have a genetic predisposition for developing AMD, e.g., those with close family members with AMD, your risk of developing AMD is doubled and if you are a smoker your risk is eight times that of a non smoker.
Smoking is a risk to your sight and it also harms the sight of to those around you. But the good news is that over time you can reverse this increased risk giving up smoking.
Smoking causes blindness and the most sensible thing you can do for your eye health is not to smoke.
Alcohol consumption:
Moderate alcohol consumption doesn’t seem to have adverse effect on eye health
Excessive alcohol consumption in pregnancy can lead to foetal alcohol syndrome (FAS), and reduced visual acuity that cannot always be rectified by glasses
Excessive alcohol consumption in combination with heavy smoking and poor diet can lead to what is called toxic tobacco-alcohol amblyopia, a condition that leads to reduced visual acuity and loss of central vision. For better eye health stay within the limits of moderate alcohol consumption set by national health departments. This is more true during pregnancy.
The importance of good nutrition:
Good nutrition is very important for both general and eye health. Your body needs daily nutrients to grow cells, repair wear and tear, protect against infection and to function properly.
There is evidence in scientific literature that poor nutrition can contribute to the formation of cataracts and the development and progression of AMD.
Nutrition in AMD:
Our body’s natural physiological activities generate ‘free radicals’ which can damage cells and prevent them from regenerating. Our body’s ability to protect and repair the oxidative damage declines as we age. As we age more of free radicals accumulate and they can damage the eye’s retina affecting our fine vision.
Our body has defense mechanisms that can neutralise these free radicals. These are called antioxidants and they have been studied extensively for their role in maintaining eye health.
The role of antioxidants:
Vitamins that act as antioxidants have been evaluated in clinical studies for their link with development and progression of AMD.
A specific high dosage of vitamins C and E, beta-carotene, zinc, and copper (known as AREDS formulation) could help to “significantly reduce the risk of developing advanced stages of AMD by about 25 per cent” for people who already had moderate AMD. However there is no treatment or remedy for the early stage of AMD. The level of vitamins and minerals in AREDS formulations is much higher than the recommended daily amount of vitamins we should consume. It is also much higher than the amount people can obtain naturally from their diet. Taking such high levels of vitamins and minerals cause other health problems and side effects. For instance
beta-carotene has been shown to increase the risk of lung cancer in smokers. If you have AMD please consult with your doctor before considering a high dose vitamin and minerals supplement. And we must bear in mind that there is no evidence in scientific literature that these supplements have any effect in early stage of AMD.
The case is different for lutein and zeaxanthin they actually may play a significant role in preventing oxidative damage to the macula thereby preventing the development of AMD rather than just slowing down its progression. Lutein and zeaxanthine are pigments also found in dark-green leafy vegetables, such as spinach, kale, broccoli, and in sweet corn. These carotenoids are important for retina function and health of macula of the eye responsible for central and fine vision.
It is important to remember that our body cannot synthesise lutein and zeaxanthin, and they need to be supplied through our diet or by nutritional supplementation. The level of these pigments in our eyes can decline over the years despite following a healthy diet, and it can be difficult to consume enough lutein and zeaxanthin to maintain the levels needed. Fortunately, serum and retinal levels of these important carotenoids can be modified by increasing dietary intake or by nutritional supplementation.
The role of dietary fat intake:
Studies suggest that a diet high in polyunsaturated fats, and particularly the consumption of fish that is rich in omega-3 fatty acids, decreases the risk of developing AMD.
The role of nutrition in the formation of cataracts:
A number of studies evaluated possible preventive effects of antioxidants nutrients on the formation of cataracts.
Recommendations on nutrition:
Rich sources of vitamins A, C and E are fruit and vegetables such as oranges, kiwis, grapefruit, dried apricots, green leafy vegetables including kale and spinach, tomatoes, peppers, raw carrots, green peas, green beans and Brussels sprouts.
Nuts, seeds, dairy products and eggs are also a source of antioxidant vitamins.
Lutein can be found in yellow peppers, mango, bilberries, and green leafy vegetables such as kale, spinach, chard and broccoli. Zeaxanthin can be found in orange sweet peppers, broccoli, corn, lettuce (not iceberg), spinach, tangerines, oranges and eggs. Many of these food types are also a rich source of antioxidant vitamins A, C and E.
In addition a healthy diet should also include a high intake of omega-3 rich fish (at least three times a week) since this has been shown to help prevent AMD. However, the recent reported AREDS2 study did not show any effect from omega-3 in reducing the risk of progression from intermediate to advanced stage AMD. There have been a number of commercial AREDS2 supplements in the market containing omega-3. However, based on AREDS2 study there is no more reason to pay for the high cost of taking omega-3+AREDS formulations that were marketed a few years ago before having had the actual study results from AREDS2 study.
We believe that a balanced diet should be sufficient to help your eyes stay healthy. But nutritional supplements can play a role where people find it difficult to eat the recommended amounts of fruit and vegetables (five portions a day), an issue particularly for older people living in nursing homes.
If you feel you need to take supplements we recommend you to talk to your doctor first, particularly if you are diagnosed with AMD.
Sunglasses:
You might never thought of buying sun glasses for protecting your eye from eye disease.
But research shows that sun light exposure is a main risk factor for cataract. The increased risk varies between 2.5 times and four times the risk of someone who is not regularly exposed to sunlight without protection, and the risk increases over time.
Damage caused by sunlight has also been linked to development of AMD. It appears that it is the blue or visible light (400-700 nm wavelength) that may increase the risk of developing AMD. Utraviolet light doesn’t reach the macula and therefore cannot harm it.
Recommendations on sunlight protection:
Based on current research it is recommended to protect your eyes against sunlight exposure. To do so, you can wear sunglasses or a wide brimmed hat, especially in the summer in the middle of the day. It is important to wear sunglasses that properly block out the light and do not let it in through the sides or top, so glasses need to be big enough and have an appropriate tint.
Conditions that increase the risk of eye disease.
Diabetes:
It is well known that people with diabetes are at risk of developing diabetic retinopathy, which if remained untreated can lead to sight loss over time.
Early diagnosis and proper treatment have shown to prevent sight loss in 90 per cent of individuals with diabetes.
It is important to know that the likelihood and severity of diabetic retinopathy increases in diabetic patients and it is likely to occur
earlier and in severe form if diabetes is poorly controlled.
There are a number of symptoms that indicate that somebody may have diabetes including excessive tiredness that cannot be
explained by other causes, being thirsty all the time or needing to go to the toilet frequently, especially during the night.
Obesity:
Being overweight or obese increases the risk of many diseases and health conditions, including hypertension, high
total cholesterol, Type 2 diabetes and coronary heart disease.
A recent review study have shown that obesity is a risk factor for all four major causes of sight loss: AMD, diabetic retinopathy, glaucoma and cataracts.
Studies show that obesity may increase the risk of developing dry AMD, which is linked to oxidative damage. The increase in the risk of developing AMD associated with obesity is:
– 1.5 times increased risk for people with a BMI of over 25.
– 2 times increase risk for people with a BMI of over 30
Also it is known that obesity increases the rate of progression of wet AMD, a less common type of AMD that can lead to rapid vision loss. People with BMI of over 25 have twice the risk for experiencing rapid progression of the disease. Similar increased risk exists for people with a higher hip/waist ratio (individuals with higher levels of abdominal fat).
People who have genetic predisposition for AMD must be more careful to avoid gaining weight since their risk increases from a four fold risk with normal weight to an eleven fold risk if they are obese
Cataracts
Evidence for a direct link between obesity and cataracts appears to be more consistent. For people whose BMI is over 30 the risk of developing cataracts can be as high as double that of people who are not overweight.
We need to keep in mind that that healthy eyes may be one of the many positive effects of a healthy weigh.
If you are aiming to reduce your risk of sight loss it is important to aim for reducing and maintaining a healthy weight. And if you already have diabetes, weight loss is even more important for your eye health.
Regular eye tests – the key to sight loss prevention
Regular eye tests – the key to sight loss prevention disease, the single most important step to prevent sight loss is regular eye tests.
This is where an eye test is an eye health check that everybody should have on a regular basis whether or not they wear glasses.
For a healthier eyes and protection of your sight stop smoking, eat healthily, exercise and protect yourself from the sun.
Sources:
– Royal National Institute for Blind (UK)