We are able to see when light rays from an object enters the cornea, which is the transparent layer covering the front of the eye. The rays then pass through the lens, which lies behind the cornea, then through a fluid medium, and finally strike the nerve layer of the eyeball, called the retina. This is the innermost layer of the eyeball. This layer has specialised cells, which are sensitive to dim and bright light, and also to colour.
The image of the object falls on the retina and is interpreted by the brain for us to visualise what it is. The whole mechanism involves the basic principles of physics, related to light, which travels in a straight line. When it travels from one medium to another it deviates from its straight path. This convergence or divergence affects the distance at which the object’s image is formed. The curvature of the eyeball, in different planes, the muscles which move the eyeballs in different directions, the transparency of the lens, the state of the small muscles which contract or dilate the pupil of the eye, the fluid in the different chambers of the eye, and lastly, the state of the retinal cells, all playa part in the functioning of the eye and our vision.
Causes and symptoms of Refractive Error
When refractive error is caused by the curvature of the eyeball, or the state of the lens, it is corrected by wearing prescribed spectacles and doing eye exercises. Here some symptoms of Refractive error.
- Blurred vision.
- Difficulty reading or seeing up close.
- Crossing of the eyes in children.
Home Remedies For The Treatment of Refractive Error
A remedy popular with many medical students of my generation:
Soak an almond in a cup of water at night. In the morning, peel and eat it with a cup of milk. It is rich in vitamin-A. On the second night, soak two almonds, and eat them the next morning. Add an almond every day for a week, till you are having seven almonds. The next night soak six almonds, and the next five, till at the end of the week you are again having only one almond. Eating these soaked almonds in an ascending and descending order is grandmother’s prescription for good eyeright and healthy ‘grey matter’. It also delays the onset of cataract. Almonds are highly nutritious and easily digestible proteins. Their brown skin is considered to be ‘heat-producing’ and also difficult to digest, and is hence discarded.
Eat plenty of carrots, red peppers, mangoes and melons. All fruits and vegetables in shades of yellow and orange, as well as green leafy vegetables, are rich in beta-carotene, the precursor of retinol.
3. Liquorice Root
Myopia or short-sightedness is benefited by the intake of a mixture of half a teaspoon of powdered liquorice root, half a teaspoon of ghee made from milk fat, and half a teaspoon of honey, thrice a day with half a cup of milk, before meals for 3-4 weeks.
4. Carrot Juice
A cup of carrot juice and one-fourth of a cup of spinach juice taken twice a day is good for eyesight. Regular intake ensures that spectacles are never needed!