The eye is one of the most important organs of the body, which enables us to see, that is, the eye is the channel of our vision.
To have an idea in simple words of the structure of the eye, the source of vision and its treatments, we reproduce below some of the relevant extracts from an article, published in the daily of Ranchi, The New Republic, in its issue, dated 10th November, 1966.
The author of the article is (Captain) B.M. Lai, then Asst. Station Director of All-India Radio, at Ranchi.
Vision and Its Source
Giving us details of the structure of the eye, Mr. Lai, describes that the eye consists of three layers of coats—the outer, the middle, and the inner. The outer layer is white, the central portion of which is transparent and is called, the Cornea.
The middle layer consists of blood vessels, which become visible just behind the cornea and are called, the Iris, with the pupil in the centre.
Directly behind the Iris, is the crystalline lens, which catches the light as it passes through the pupil and focuses it on the retina of the inner layer. Attached to the lens is the ciliary muscle, which controls the contraction and expansion of the lens.
The retina is an extremely thin and delicate membrane. No sight is possible, if the retina is destroyed.
Let us see how the actual process of seeing takes place. The light rays enter the eyes through the pupil and pass through the crystalline lens, which being convex in shape, causes them to converge on the retina forming an image.
The radiant energy is then converted by chemical action into the nerve impulses, which are transported by the optic nerve to the brain and vision is the result. Thus, it can be understood that it is the brain, or the mind, that sees. The eyes are only its instrument.