To paraphrase Shakespeare “Knowledge is in the eye of the beholder”. Taking time to understand the complicated workings of the eye will allow you to elevate and prolong the health of your vision.
How does the eye work?
There are three grouped layers of the eye. These are:
- The External Layer, this is made up of the Sclera and the Cornea. The Cornea is the transparent lens that is the outer most layer of the eye. It covers the pupil (black) and the iris (coloured) sections of the eye. Its role is to refract light, controlling how much or how little enters the eye. The Sclera is the white of the eye. It is made of a collagen-like substance surrounded by elastic fibres.
- The Intermediate Layer, This is made up of two chambers the anterior and posterior. The anterior chamber is found between the cornea and the iris, filled with aqueous humour. Whereas the posterior is made up of the Choroid. This is a pigmented area which has a great vascular blood supply.
- The Internal Layer, is made up the retina, which is the visual component of the eye. It’s incredibly complicated and layered with numerous cell types including ganglion, rod, cone and bipolar cells. The cells of the retina are densely located behind the pupil where majority of the light hits. A very basic explanation of how this functions is that the photosensitive Rhodopsin and Opsin pigments within the rod and cone cells receive and process different coloured wavelength of light. The presence of a light photon causes it to change its structure and undergo a complicated number of processes that stimulates neural processing and allows us to decipher the world around us. Both of these pigments are derived from Vitamin A.[1,2]
What Diseases or Disorders can effect the eye?
Due to the complex nature of the eye and the multiple layers that form it there are numerous disease and disorders that can be problematic. One of the most common problems is long and short sightedness. It’s seen in all age populations of the nation but is most typically a problem associated with ageing. The number of people with symptoms is believed to be increasing as screen time is at an all time high. Myopia, or short sightedness is most common with every 1 in 3 people suffering from symptoms of it. Other diseases include Age Related Macular Degeneration (AMD), Cataracts, Conjunctivitis, Glaucoma, and Diabetic Retinopathy.
What can you do to improve eye health?
Some disorders are unavoidable and are coded into the genes, however, precautions can be taken to protect the eye from the effects of ageing and experiencing damage.
The old wives tale states that eating carrot will help you see in the dark, this is not necessarily true. Carrots are full of Vitamin A but eating copious amounts of them will not be hugely beneficial. As previously mentioned, visual capabilities depend on essential pigments called Rhodopsin and Opsin that are derived from Vitamin A and Carotenoids. According to the European Food Standards Agency (EFSA) Vitamin A is responsible for the maintenance of normal vision. It has also been linked to a reduction in dry eyes and night blindness. Vitamin A is found in foods such as beef, chicken, dairy products and animal liver. Additionally, carotenoids Lutein and Zeaxanthin. According to studies they are linked with prolonging normal eyesight. These are found in majority of vegetables such as Kale, Butternut squash and Spinach. Also, Omega-3 Fatty Acids have been linked with Ageing Macular Degeneration (AMD), high consumption in the diet is thought to slow the progression of AMD. Omega 3 fatty acids are most typically consumed in supplement form but can of course be found naturally in oily fish such as Salmon and Mackerel .Vitamin C is found in the lens at a concentration 60 times higher than that of the circulation. Vitamin C is a potent antioxidant used to promote antioxidant properties as a protection method for the eyes. This can be said about any antioxidant including Grape seed extract, Astaxanthin and Bilberry Extract. Free radicals are generated from the sun, from smoking, alcohol or chemicals. They are molecules that have one missing electron from the structure which makes them highly reactive and highly damaging. Their reactivity comes from the need to complete their electron number by stealing an electron from another structure, called oxidation. Oxidation is responsible for damage to DNA, Proteins and Lipids.
All of the nutrients and extracts mentioned above can either be consumed in the diet or via supplement form. When choosing a supplement for you eyes make sure it includes potent antioxidants, Vitamin C or Vitamin A derivatives.
Other tips to maintain eye health
- Have regular check ups with your optician.
- Watch for typical symptoms of eye problems in your children, such as rubbing eyes, squinting or frequent infections.
- Drink responsibly as alcohol prevents the processing of Vitamin A and leads to deficiencies that can damage your eyesight.
- Know your family’s eye history.
- Quit smoking. Cigarette smoke appears to release chemicals that causes rapid progression in degeneration of the eye structure, which has been shown to progress the disease state of AMD.
- Wear sunglasses as regularly as you can. UV rays can be incredibly damaging to the outer layers of the eye.
- Wear the correct strength glasses and lenses. If you feel your self squinting or straining to see, book an appointment with your optician.
- Give yourself regular breaks from computer, television and phone screens.
- Find a supplement specifically tailored to eye health. 
- Kolb.H. (2012). Gross Anatomy of the Eye by Helga Kolb. Available: http://webvision.med.utah.edu/book/part-i-foundations/gross-anatomy-of-the-ey/.
- Pocock.G, Richards.C, Richards.D. (2013). 12.5: Sensory System- The physiology of the eye and visual pathways. In: Pocock.G, Richards.C, Richards.D Human Physiology . 4th ed. Oxford: Oxford University Press. Pg 199-215.
- Heiting, G. (2014). Nutrition for Healthy Eyes. Available: http://www.allaboutvision.com/nutrition/nutrition_summary.htm.
- Greene,A. (2012). 10 Tips For Healthy Eyes. Available: http://www.webmd.com/eye-health/features/tips-for-healthy-eyes#1.