To measure this, mark the second lens at the ordered centration distance, place them back onto the focimeter
with this mark centred and read the power
Ask the patient if they have any other spectacles in addition to the pair about to be checked (eg, reading spectacles, sunglasses, a spare pair, or a newer pair they can't wear) and be sure to focimeter
all of these.
can be used to discover the powers of the cleaned RGP lenses and the results compared to those noted in the records.
After developing this first instrument, the academic support officer went onto build, amongst other things, a progressive lens measurement machine that he patented, and a scanning focimeter
which second-year optometry students at Aston University use today.