The farther a convex lens is from the eyes the more it relieves accommodation because its focus is brought by so much nearer to the retina, hence a weak lens at a distance has the same effect as a more proximal and stronger one. For this reason, old people sometimes prefer to wear their spectacles on the tip of the nose."In this reason, old people sometimes prefer to slip the concave reading glasses for down towards the tip of the nose, in order to make a weak glass to do the office of a stronger glass in improving the distinctness of the print". ___ The optician's manual