Effective range of measurement:
Binocular pupillary distance:45mm~82mm
Left or right pupillary distance:22.5mm~41mm
Indication error:≤0.5mm
Rounding error:≤0.5mm
Distance of target:30cm~∞
Power supply: DC 3V,5# AA rechargeable battery
FVP-PI PD Meter Ophthalmic Pupil Meter Digital Pupilmeter