Different Eye ProblemsSponsored LinksJust like a camera, the eye works by focusing light rays that enter its lens. The light enters into the first transparent layer of the eye called the cornea. The cornea acts by focusing the light through the pupil and into the next layer called the crystalline lens. This then focuses the light further to create a clear image into the inner surface of the eye called the retina. Finally, the optic nerve transmits the image into our brain. A camera cannot produce a clear photograph when the refracted light is not focused accurately onto the film. The same happens with the eye; when the cornea and crystalline lens are not able to properly focus the light onto the retina, the result is a blurred vision. This inability to focus light is the cause of four of the most common vision problems. These are: - Near-sightedness Near-sightedness (myopia) is a condition wherein a person can see nearby objects clearer than distant objects. It is caused when the eye is unable to focus the light precisely onto the retina. This occurs when the cornea and the crystalline lens have too much combined focusing power or when the eyeball is too short. In both cases, the light is instead focused in front of the retina which causes the blurred vision. Far-sightedness (hyperopia) is a condition wherein a person can see distant objects clearer than those nearby. In this condition, the combined focusing power of the cornea and the crystalline lens is too little or the eyeball is too long. In both cases, the light is focused behind the retina which also results in a blurred vision. Astigmatism is a condition wherein the eyes focus light unevenly. This happens when the shape of the cornea is distorted. Normally, the cornea has a basketball-like spherical shape; but with astigmatism, it has more of an oblong shape like that of a football. People with this condition usually also suffer from either near-sightedness or far-sightedness or both. Presbyopia (which comes from the Greek word for “old vision”) is as its name implies. It is an age-related condition wherein the eyes lose its focusing ability. This condition usually occurs in people between forty and fifty. Its starts when people notice that they can no longer read as clearly as before and will have to place reading materials further away to get a clearer vision. This condition is usually corrected by using reading glasses or bifocals. Presbyopia occurs when the crystalline lens losses its elasticity and can no longer adequately adjust its shape to focus on nearby objects. Presbyopia is commonly mistaken for far-sightedness or hyperopia; but the two conditions are not the same. Whereas presbyopia results in the inability of the crystalline lens to refocus from distant to up close, far-sightedness is brought about by the inadequate combined focus of both the cornea and the crystalline lens. Although both conditions result in a blurred close-up vision, hyperopia can also cause a blurring of distant objects. Another difference is that presbyopia is age-related and may start at mid-thirties, whereas, hyperopia may come about at any age and may even be inborn. Presbyopia can be a condition by itself or may occur along with near-sightedness, far-sightedness and astigmatism. Get educated on the following eye surgery related topics: |
