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An eye which suffers from myopia as well as hypermetropia is said to be presbyopic. A man suffering from this defect cannot see objects placed at any distance from him, distinctly. The weak accommodating power of the eye lens causes this defect. In old age, the muscles becomes loose and so does the accommodating power of the eye lens. The eye lens fails to form a distinct image of an object at any distance from the eye. To correct the defect, bifocal lenses are used, concave to see distant objects and convex for reading purposes.