collect information about different types of eye defects from your nearest eye specialist or optical shop and write a report
Answers
There are different types of eye defects. Some of them are:
Myopia or nearsightedness is a defect of vision in which the near objects can be seen clearly but the far objects appear blurred. In this the image is focused in front of the retina rather than on it. This can be because the eyeball is too long or the refractive power of the eye's lens is too strong. It can be corrected by wearing glasses or contacts with concave lenses.
Hyperopia or farsightedness is a defect of vision in which far objects can be seen easily but there is difficulty with near vision. In this the image is focused behind the retina. This happens when the eyeball is too short or the refractive power of the lens is too weak. It can be corrected by wearing glasses or contacts that contain convex lenses.
Astigmatism is a defect when all the light rays do not fall on a single focal point on the retina, some focus on it, some in front of it and some behind it. This happens due to the non uniform curvature of the cornea. A symptom of astigmatism is that when a person looks at a pattern of lines placed at various angles and the lines running in one direction appear sharp and those in other directions appear blurred. It can be corrected by using a special spherical cylindrical lens which is placed in the out of focus axis.
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