Age-related Macular Degeneration (AMD) is a popular topic. However, cataracts is the leading cause of blindness worldwide. In the UK, for example, the most common eye diseases are split into AMD (40 per cent), glaucoma (13 per cent) and diabetic retinopathy (eight per cent).
I have written about AMD in the past. However, diabetic retinopathy hasn’t been a subject I’ve tackled, hence this explanation as to how it occurs.
Diabetes can affect your eye in a number of ways.The most serious eye condition associated with diabetes involves the network of blood vessels supplying the retina. This condition is called diabetic retinopathy.
The changes in blood sugar levels resulting from diabetes can affect the lens inside your eye, especially when diabetes is uncontrolled. This can result in blurring of vision, which comes and goes over the day, depending on your blood sugar levels.
A longer-term effect of diabetes is that the lens of your eye can go cloudy. This is called a cataract.
Not everyone who has diabetes develops an eye complication. Of those who do, many have a very mild form of retinopathy, which may never progress to a sight-threatening condition.
The most serious complication of diabetes for your eye is the development of diabetic retinopathy. Diabetes affects the tiny blood vessels of your eye and if they become blocked or leak, then the retina, and possibly your vision, will be affected.
The extent of these changes determines what type of diabetic retinopathy you have. Forty per cent of people with type 1 diabetes and 20 per cent with type 2 diabetes will develop some sort of diabetic retinopathy.
If diabetic retinopathy progresses, it can cause the blood vessels in the retina to become blocked
If diabetic retinopathy progresses, it can cause the blood vessels in the retina to become blocked. These blockages, when affecting a significant part of the retina, can result in areas of the retina becoming starved of oxygen. This is called ischaemia.
If this happens, your eye is stimulated into growing new vessels, a process called neo-vascularisation. This is nature’s way of trying to repair the damage by growing a new blood supply to the oxygen-starved area of your retina.
Unfortunately, these new blood vessels are weak, and grow in the wrong place, on the surface of the retina and into your vitreous gel.
As a result, these blood vessels can bleed very easily, which may result in large haemorrhages over the surface of the retina or into the vitreous gel.
These types of haemorrhages can totally obscure the vision in the affected eye as light is blocked by the bleed and the blood in the vitreous gel.
For many people, with time, the blood can be reabsorbed and their vision can improve. But for others, these haemorrhages may keep happening and the blood may not fully reabsorb. This can lead to more permanent loss of sight (www.diabetes.org.uk/retinopathy).
There are nutrients which can help the eyes. There is no doubt that, once again, lifestyle has a massive effect on eye health. For example, fat soluble nutrients such as vitamin A are a powerful antioxidant, as is vitamin E.
Carotenoids help by absorbing blue light, which is damaging to our eyes. In addition, lutein and zeaxanthin absorb blue light and act as antioxidants.
Zeaxanthin is not well known but it is one of the most common carotenoid alcohols found in nature. It is important in the xanthophyll cycle. Synthesised in plants and some micro-organisms, it is the pigment that gives paprika, corn, saffron, wolfberries and many other plants and microbes their characteristic colour.
Xanthophylls such as zeaxanthin are found in highest quantity in the leaves of most green plants, where they act to modulate light energy. Animals derive zeaxanthin from a plant diet. Zeaxanthin is one of the two primary xanthophyll carotenoids contained within the retina of the eye. Within the central macula, zeaxanthin is the dominant component, whereas in the peripheral retina, lutein predominates.
So how do we convert this into food which will help our eye health and can be introduced into our daily diets? As always, fruit and vegetables are a massive part of an eye-health diet. They include the green and yellow pigment foods including peppers, mango, bilberries, sweetcorn, green leafy vegetables and eggs.
Food that contains zeaxanthin includes broccoli, peppers, corn and lettuce. Also brussel sprouts, green beans, spinach and peas. Lutein is contained in spinach, corn (maize), green leafy vegetables and eggs, among other foods.
Taking vitamin C can help ocular disease, so the usual foods that contain vitamin C are essential, as well as supplements. Other foods and supplements for eye health are vitamin B and omega 3 fatty acids (DHA, EPA), which are critical. Other supplements include zinc selenium and taurine.
A study in the Netherlands, which has endorsed eye health through diet, included 5,836 participants over the age of 55, who were assessed on dietary intake through a food frequency questionnaire. The participants were followed for eight years. At the end, there were 4,170 participants left. Classed as a good study, 560 participants were diagnosed as having AMD. The conclusions were that, through a high dietary intake of the mentioned foods and supplements, there was a reduced risk of AMD.
Many other good studies also proved that foods or supplements helped with eye health, even if the regime was begun later in life.
kathryn@maltanet.net