Prescription of presbyopic lens to a 50 year old emmetropic individual?

A rough estimate of the power of presbyopic glasses in an emmetrope can be made from the age as follows:- 40 years: +1.00 DS 45 years: +1.25 DS 50 years: +1.75 DS 55 years: +2.00 DS 60 years: +2.25 DS 65 years and above: +2.50 DS