question_answer 24)

Does short-sightedness (myopia) or long.sightedness (hypermetropia) imply necessarilythat the eye has partially lost its ability ofaccommodation ? If not, what might cause thesedefects of vision ? 

Answer:

Name three defects are basically differenttype of defects. (a) Hyperopia (Hypermetropia) i.e. longsightedness. It is long sightedness (or farsightedness) of eye i.e. near objects are notclearly seen but the objects which are farway (i.e. distant objects) from the eye areseen clearly. This defect is removed by usingsuitable convergent lens (Figure A). (b)Myopia i.e. short sightedness. It is shortsightedness (near sightedness) of eye i.e. faroff objects are not clearly seen but the nearobjects are clearly seen. This defect can becorrected by using suitable divergent less(Figure B). (c)Presbyopia i.e. loss of power ofaccommodation. In this defect both far offand nearer objects are not clearly seen. Thisdefect is generally corected by using bi-focallenses.