HOW WILL WE INCREASE THE RANGE OF LENSOMETER?

the range of lensometer can be increased by placing a trial lens of known power and opposite sign alongwith the high power prescription to be checked
.for example* ur lensometer has readings marked upto 20 diopters. . . .u are given a lens power greater than 20, eg -24 diopters. . . . .place a plus 10 dioptr lens alongwith ur unknwn lens power (i.e. -24D). . . .ur lensometer will get focusd at -14 . . .nw add the deductd 10 dioptrz. . . .u wil get the final power i.e. -24 diopters.