The human eye is a wonderful thing. It lets us view things. They can give us another eye color, or we could just use them to simply view things. But it’s not that simple you see. Some people aren’t that lucky, and have impaired vision. This includes near-sightedness and far-sightedness. To begin though we must understand how the eye works, and why it works that way.
First is the cornea, which is a clear dome that covers the front of the eye. The cornea accomplishes the majority, which is about 70%, of the bending of light rays.
The crystalline lens finishes the rest of the 30% of focusing of light. It helps to “fine tune” vision, and it has the ability to change shape so that it focuses on one thing, normally near. When it becomes cloudy, it is called a cataract. Sometimes age has some thing to do with cataract. Unlike the cornea, the lens can be made to change its shape (and, therefore, its refractive power) often and however many times it pleases. Using its ability to change shape, the lens allows the eye to change its focal point. Changes in the shape of the lens will allow a normal eye to focus on near objects.
Then there is the iris, which really doesn’t do anything except give the eye color, which I guess is pretty cool. It would be weird if everyone had black eyes, or brown eyes, so variety is good.
The pupil is the little opening in the middle of the iris. It can change shape, as it controls the amount of light that enters an eye. When it is bright the iris will shrink, therefore not letting in as much light. When it is dim the iris will grow, therefore letting in more light.
The Essay on If I Could Change One Thing About Me
Settings: – At Home – In School Conflict: -When I do have a problem with focusing on my studies, and at home, especially to my mom. Character: – My family – My friends Thesis Statement: – Well, there are many things I would like to change about myself, but If could change one thing about me, it would probably my attitude of being lazy. If I wasn’t so lazy I ...
In the back of the eye there is nerve tissue that senses light and is called the retina. “Specialized cells called rods and cones convert light energy into nerve signals that travel through the optic nerve to the brain” I quoted that from Grolier encyclopedia 1996, simply because it was the best way to put it.
Now that the basic knowledge has been taught, we move on to the next part, near-sightedness.
Near-sightedness is a condition a lot of people suffer from. The odds of you being near-sighted are one in four, but that’s only if you are in your early teens. The degree of it being wrong can be as low as –1.00 degree, or as high as over –6.00. Also known as Myopia, it is not caused by reading at an early age, prolonged reading, reading in the dark, watching TV too closely, wearing glasses too strong, wearing glasses too weak, or other similar activities. Myopia is commonly associated with high I.Q.s, but that’s because they tend to read more. Also, Myopia is inherited, only to a certain extent, but at the age of 18 they tend to stable out so the degree doesn’t rise anymore.
Why you might ask, what’s wrong with the eye? Well in a nearsighted eye, the cornea is too steeply curved for the length of the eye, causing light rays to focus in front of the retina. Distant objects appear blurred or fuzzy because the light rays are not in focus by the time they reach the retina. So basically the higher the myopia, the more blurred distant things get.
Next we go to Farsightedness.
Farsightedness is much less common in people then Myopia. Also known as hyperopia, the condition typically stays within the range of +1.00 and +4.00 but to the extreme it goes to +8.00.
What’s wrong with the eye this time? Well this time it means that the parts of the eye are simply to short for their power! That’s it. Distant objects are blurry, but nearer ones are even worse!
In closing, the eye is crucial to our daily life, and without it life would be hard and now that I know more about it I feel I will treat it better then usual.
The Report on How Eyes Use Light to Manage Body Clocks
New Evidence on How our Eyes use Light to Manage our Body Clock - University of Surrey Groundbreaking Study Results August 20, 2001 A new study published this week shows for the first time that the human eye is sensitive to short wave length visible light and transmits information to the body clock in a way that may make it possible to manipulate waking and sleeping rhythms. This new data, gained ...
