Q: How do you calibrate an auto refractometer?

A: Select the calibration liquid. Some models use a special calibration liquid while others use distilled water.

Lift the daylight plate and place 2 to 3 drops of the calibration liquid on the prism assembly. Close the daylight

plate and allow the calibration liquid to spread across the prism without any dry spots.A study conducted in 2015

found that autorefractors were able to determine refractive errors within 0.2 diopters of the accepted standard, and

that they even exceeded human error standards in certain cases.