Question
Wed January 18, 2012 By: Gautam Udayabhanu

Can u please tell the formula 4 findinding out the power of lense when far point and near point are given

Expert Reply
Thu January 19, 2012
Thin lens power formula,
P = O + I
To correct myopia we need a lens that will image an object located far away onto the myopic far point.  The myopic far point is the farthest distance from the eye that an object can be so that the eye is still able to focus its image onto the retina.
P = 1/ (object distance) + 1/- (far point distance)
Similarly , hyperopic near point is the closest distance an object can be to the eye so that its image is focused onto the retina. 
P = 1/ (object distance) + 1/- (near point distance)
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