... Sphere: 0.0 to -29.50 Diopters, step: 0.25,0.50,1,3 0.00 to ... +26.75 Diopters,step: 0.25,0.50,1,3 Cylinder: 0 ... .0 to ± 8.75 Diopters,step:0.25 Prism form: Base up,base down, ... in,base out Binocular balance: Rotary prism,polarizing filter and R & G filter Cross cylinder: ±0.25D ,± ... both sides Corneal alignment: 12 to 20mm by 2mm step and 13.75mm Field of view: 35° Power source ...