The regulation function of the eye is the ability of the eye to focus on near objects and is mainly divided into two aspects: regulation power and regulation sensitivity. You can also roughly obtain the value of accommodation power by measuring the near point of adjustment of the eye by extending the arm forward, extending the finger, pointing the finger to the face, and using the eye to see the fingerprint on the finger, gradually moving the finger from far to near to the eye until you see the fingerprint blurred, and then recording the distance between the finger and the eye. The reciprocal of this distance is the eye adjustment force, such as 0.25 m when the fingerprint becomes blurred, the eye adjustment force is 4.0 D. The adjustment sensitivity check must be done with the help of relevant inspection equipment, which can be checked using a reversal shot.