Presbyopia typically peaks around +2.50 The reason for this is the normal natural lands in adults has converging or of 2.50 to 3.00 diopters. As we age from 40 to 60 this power keeps getting reduced from 3.00 to 2.50 to two and so on to make up for this the reading glasses have to be added of a prescription, so the total is 3 so when the eyes power decreases the reading glasses increase till they reach 3 diopters but most commonly people are happy with +2.50