(i) Let the power at the far point be Pf for the normal relaxed eye.

With the corrective lens the object distance at the far point is ∞. The power required is

The effective power of the relaxed eye with glasses is the sum of the eye and that of the glasses P_{g}.

(ii) His power of accommodation is 4 diopters for the normal eye. Let the power of the normal eye for near vision be P_{n}.

Then 4 = P_{n} – P_{f }or P_{n} = 64 D.

Let his near point be x_{n}, then