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TeachLearnWeb
DEFECTS OF VISION AND THEIR CORRECTION
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TeachLearnWebMIND MAP
DEFECTS OF VISION AND THEIR CORRECTION
GET STARTED DEFECTS SUMMARY
TeachLearnWeb INTRODUCTION
• There are lots of vision defects that people are suffering from.
• These defects include Nearsightedness, Farsightedness , and Presbyopia
• These defects can be corrected by the use of suitable spherical lenses.
• The vision becomes blurred due to the refractive defects of the eye.
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TeachLearnWeb DEFECTS OF VISION AND THEIR CORRECTION
Myopia: (nearsightedness) • This is a defect of vision in
which far objects appear blurred but near objects are seen clearly.
• The image is focused in front of the retina rather than on it usually because the eyeball is too long or the refractive power of the eye’s lens too strong.
• Myopia can be corrected by wearing glasses/contacts with concave lenses these help to focus the image on the retina.
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TeachLearnWebDEFECTS OF VISION AND THEIR CORRECTION
Hyperopia: (farsightedness)
• This is a defect of vision in which there is difficulty with near vision but far objects can be seen easily.
• The image is focused behind the retina rather than upon it.
• This occurs when the eyeball is too short or the refractive power of the lens is too weak.
• Hyperopia can be corrected by wearing glasses/contacts that contain convex lenses.
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TeachLearnWebDEFECTS OF VISION AND THEIR CORRECTION
Presbyopia
• The power of accommodation of the eye usually decreases with ageing.
• For most people, the near point gradually recedes away. They find it difficult to see nearby objects comfortably and distinctly without corrective eye-glasses. This defect is called Presbyopia.
• Eyeglasses with bifocal or progressive addition lenses (PALs) are the most common correction for presbyopia.
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TeachLearnWebSUMMARY
• There are lots of vision defects that people are suffering from and they can be corrected by use of suitable spherical lenses.
• Myopia (nearsightedness) is a defect of vision in which far objects appear blurred but near objects are seen clearly.
• Hyperopia (farsightedness) is a defect of vision in which there is difficulty with near vision but far objects can be seen easily.
• Presbyopia arises due to the gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens.
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