Objective it's law is not in check the subjective consciousness, but through the objective methods for determination of the eye point, this is the eye of the refractive system judge refractive status.

Objective test has the following kinds:

(1) the inspection method of detection method of the shadow is using diagonal (or concave lens) will light projection to check the intraocular in rotation of the mirror, meanwhile, after examination by shadow mirror hole observation of light shines out of the fundus examination in the pupil area, and the movement of the DiJia right, so as to determine the lens of the eye refractive properties and degree. Can be used in children, low intellectual, deaf and amblyopia patients.

(2) the automatic subjective refractometer method (computer it's law) : this method inspection speed, no pain, susceptible to patients, and easy to grasp, which can be used on group, a large amount of it's refractive census outpatient department and eye disease treatment process changes observation refractive. But because of the degree of cooperation by patients adjust action and instrument accuracy, the influence of factors, so check the accuracy of the results are still there are some problems, especially for children and teenagers, the inspection results of myopia much error. When it's need to be the inspectors to always look at target in the machine, and, therefore, not solid depending on the patients, such as not cooperate with child, nystagmus patients, under vision (high myopia, refractive interstitial opacity, YanDeBing) who could not use automatic subjective refractometer it's.