A optometry meter is used to check the convergence of light after entering the eyeball. It uses the state of emmetropia as the standard to measure the difference in vergence and dispersion between the examined eye and the emmetropia.

The refractometer does not require pupil dilation and can quickly measure the refractive power. The optometry results are all automatically printed without conversion. Generally, a patient can be measured in a few seconds to a few minutes, and the degree of refractive error can be quickly determined, providing more accurate refractive power and interpupillary distance for lens correction.