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Defects of the Eye

Updated on January 21, 2013

Myopia: Myopia, more commonly known as near-sightedness is a vision condition in which you see close objects clearly, but objects far away seem blurry. It occurs if the eyeball is too long or the cornea has too much curvature. This causes the light entering the eye to be incorrectly focused, resulting in distant objects looking blurry. Myopia can be corrected by wearing glasses with a concave lens. The lenses in the glasses change the light and curve so that the image will fall shorter/farther away that what you are seeing. This means that whatever your eye requires, the lens will be adjusted to fall on your retina and not away from it. Once the image hits the retina properly, your brain can interpret it correctly and the images blurriness goes away.

Hyperopia: Hyperopia is commonly known as far-sightedness. It is a refractive error which causes the eye to incorrectly bend or refract light. This causes distant images to be clear but closer images to be out of focus. The refractive parts of the eye are the cornea and the lens. The cornea and the lens are both curved to perfection, if either of these have a slightly abnormal shape it causes hyperopia, because light is focused behind the retina. Once again glasses with a convex lens, can correct these eye defects. The glasses could be in the form of bifocals, trifocals or even just reading glasses. The glasses will help to compensate for the normal shape of the eye so the light rays hit the retina normally, providing you with a clear and a non-blurry vision.

Presbyopia: Presbyopia (meaning ‘aging eye’) is an age related condition that causes increased difficulty in seeing things very close to your eye. As you age, the lens of your eye becomes more rigid, it becomes harder to read at a close range. Glasses or bifocals have distance vision prescriptions on the top and bottom of the lens. The bottom half of the lens will enable you to be able to see things that our closer to you, while the top half lets you see objects at a far distance. Reading glasses can also be used as an alternative to this. They work like magnifying glasses; the lenses enlarge the object to be focused. This reduces the need for our eyes to tense and squint and corrects the eyes inability to focus properly.


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