... quality. Auto Phoropter,view testerSpecifications Sphere: 0.0 to -29.50 Diopters, step: 0.12,0.25,0.50,1,3 0 ... .00 to +26.75 Diopters, step: 0.2,0.25,0.5,1,3 ... Axis: 0°to 180° step:1°,5°,15° Prism: -20 to +20, step:0.1,0.5,20Prism form: Base up,base down,base in ... .00D or+1.50 both sides Corneal alignment: 12 to 20mm by 2mm step and 13.75mm Field of view: 35° Power ...