The prism effect produced by moving optical center of presbyopic glasses was put on the right and left lenses averagely by 1/2-1/3 degree of exophoria.

Aim To study the effect of wearing progressive multi-focal spectacles on phoria in the teenager nearsighted.

Phoria at distance and near, positive and negative relative accommodation(NRA/PRA), accommodative convergence and accommodation response were measured. Results Response AC/A ratio of P. M.