Making well-crafted glasses involves many measurements. One of those is the ever-important distance between the pupils of the wearer. They are important because they determine where the focus of the lenses will be. Failure to measure the distance between the pupils can result in bad fit, the glasses not fulfilling their purpose and probably damaging the eyes of the wearer further. This is why precise measurement of inter-pupillary distance is vital for a good optician.
With the latest in micro-electronics and optics measurement, this pupil distance meter has been configured so that the maximum margin of error when measuring and rounding the distance is 0.5mm, which is quite accurate.
The distance between the pupils is measured by tracing the pupillary light point and then measuring light in a direct line. This can be done both for one eye (monocular way) and for both eyes (binocular way). This type of measurement is more precise than all the other methods, so it is widely used by opticians everywhere.
Effective Range of Measurement: Binocular pupillary distance: 45 ~ 82 mm
Left or right papillary distance: 22.5 ~ 41 mm
Indication Error: ≤ 0.5 mm
Rounding Error: ≤ 0.5 mm
Distance of Target: 30 cm ~ ∞
Power Supply: DC 4.5 V; 2 x 7# AAA Battery (Product is updated, it only needs 2 batteries. Batteries is not included.)
Time for Automatic Shut-off: About one minute after stopping operation
Dimensions: 265 x 200 x 80 mm
Weight: 0.8 kg