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Condition - Precious Eyes

By Cathy Robinson BSc (Hons) DipNutMed

World Sight Day takes place in October each year. Visit www.vision2020.org for more details and for information about fund-raising opportunities.

It is said that our eyes are the windows to our soul, and vision is something precious that we all wish to conserve. 

Firstly, let’s have a look at the structure of the eye. Our eyes can be likened to a camera. Light enters the eye through a small hole called the pupil. Each eye has a lens, which focuses images on the retina, a bit like a camera film. The coloured part of the eye, the iris, controls the amount of light entering the eye by closing when light is bright and opening when we are in dim light. The image formed on the retina is transmitted to the brain by the optic nerve. A transparent sheet called the cornea protects the eye. A jelly-like substance called vitreous humour fills the space between the lens and the retina, while the lens, iris and cornea are nourished by a clear watery liquid called aqueous humour.

Looking after your eyes
 

It is a good idea to get the health of your eyes checked out on a regular basis. It’s an incredible statistic that one in ten British adults have never had an eye examination, despite one being recommended by eye health professionals once every two years, while 85% of us admit to having problems with vision. Indeed, new technology has enabled an optician to take a photograph of the back of the eye to detect any problems at an early stage.

Eye problems
 
Screen fatigue
 

Prolonged computer use can put strain on our eyes and lead to problems known as screen fatigue. This is characterised by symptoms such as headaches, eyestrain and problems with close and long distance vision. To reduce strain on the eyes, it is recommended that computer users take frequent breaks to rest their eyes every 20 minutes or so, minimise any glare or reflections from the computer screen, position the monitor an arm’s length away and keep eyes level with the top of the screen.

Glaucoma

Glaucoma occurs as a result of damage to the optic nerve caused by increased pressure within the eyeball, known as intraocular pressure. This is usually as a result of the fluid within the eye, the aqueous humour, not draining away adequately. Recent studies have found a link between reduced blood flow to the optic nerve of the eye and the development of glaucoma. Glaucoma initially causes few symptoms, but leads to a gradual deterioration of vision, particularly peripheral vision.

In order to detect glaucoma early, it is recommended that intraocular pressure and visual field be checked at least every two years during a routine eye test.  

Macular degeneration

Macular degeneration is a slow deterioration of the cells in the macula, a tiny yellowish area near the centre of the retina. This deterioration affects central vision, while peripheral vision is unaffected. Macular degeneration is thought to be associated with an excess of free radicals within the eyes. These can be formed as a result of light entering the eye.

Cataracts
 

Cataracts are a deterioration of the transparent lens, which becomes more opaque. Cataracts are one of the major causes of age-dependent visual impairment and blindness. The prevalence of cataracts worldwide is associated with the intensity and duration of sunlight, so it appears that free radicals formed by light hitting the eye may also play a role in the development of cataracts. This oxidative stress on the eye results in a clouding of the lens, so light can no longer be transmitted clearly to the retina. Cataracts grow very slowly, so will only affect vision after a number of years.

Nutrients important for eye health

The eyes are like any other organ in the body and have their own unique set of nutritional needs.

Vitamin A is important for the formation of a substance called rhodopsin, also known as visual purple, the pigment essential for night vision.

Selenium is concentrated in the lens. Research has found that selenium is much lower in lenses with cataracts. Selenium can be found in Brazil nuts and mushrooms, as well as fish.

Zinc concentration is especially high in the retina. Zinc is found in shellfish, meat, sesame seeds and pumpkin seeds.

Lutein and zeaxanthin, two of the most important antioxidants for eye support,are carotenoids found in the macula of the retina and the lens. Zeaxanthin is concentrated in the centre of the macula, and lutein in the periphery. Carotenoids are the pigments that give foods their bright colours, and are found in dark green leafy vegetables, such as spinach, broccoli and kale, as well as eggs, yellow peppers, corn and peas.

Astaxanthin is an antioxidant that appears to be able to cross the blood/retinal barrier and offers protection to the eyes against damaging free radicals, which is especially important in safeguarding against macular degeneration.

Lycopene, a red pigmentfound in red-fleshed fruits, such as tomatoes and red grapefruit, is another carotenoid antioxidant important for eye protection.Its absorption in the body improves when ingested with a good-quality oil, such as olive oil.

Bilberries contain antioxidant compounds known asanthocyanins,which may help to support the tiny capillaries that supply blood to the eye. Research has also suggested that these substances may help in the regeneration of rhodopsin.

Blackberries have antioxidant properties three times the potency of blueberries.

Magnesium. Low levels of magnesium in the body have been linked to poor ocular blood flow, a risk factor for glaucoma. Magnesium can be found in green leafy vegetables, nuts and wholegrains. However, magnesium deficiency is common in the UK, particularly in the elderly.

Gingko biloba has traditionally been used in connection with poor circulation but has also been shown to have antioxidant capabilities.


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