1. Corneal status
During the optometry, the examinee will stare at the optotype of the computer refractometer. If it is found that the center of the cornea is not in the center, the Kappa angle is relatively large.
2. Changes in pupils
The pupil can maintain the visual axis at the center of the cornea and lens, and can eliminate the spherical aberration and dispersion of the refractive interstitium of the eye when the pupil narrows. If during the optometry process, the customer's pupil changes rapidly, it means that the adjustment flexibility is good (more common in children or young people); on the contrary, if the pupil changes slowly during the examination, it means that the adjustment flexibility may be poor, or there may be slow adjustment, The adjustment force is poor, and it is necessary to focus on the inspection of the visual function.
3. Changes in refractive data
After multiple measurements, when the deviation and fluctuation of the spherical power of each measurement result is large, the subject may have a large adjustment force, and the negative spherical lens is often too high, and the positive spherical power is low, or there may be adjustment problems. In the visual function examination, the focus of adjustment can be checked.
If it is found that the degree and axial direction of the cylinder are unstable during computer refraction, the cross cylinder adjustment should be done to determine the axial direction and degree of the cylinder when the comprehensive refractometer is calibrated.