available in +/-1.00
Basic low vision techniques may include demonstrating larger changes in the lenses - rather than 0.25 diopter steps, the low vision doctor may use 1.00 diopter changes as needed - we suggest the use of stronger cross cylinder test pieces to test for astigmatism - a trial frame is used with a cross cylinder +/- 1.00 to determine the power and position of the astigmatism - the patient is able to see a larger difference in the change - cardboard box