Based on the results of a binocular optometry examination, a clear diagnosis of alternating eyes can be made. Optometry is the examination of the aggregation of light rays after they have been incident on the eye, and it measures the degree of aggregation and dispersion differences between the examined eye and the orthopic eye, using the state of the orthopic eye as a standard. Since many people are almost always associated with eyeglasses in their lifetime, optometry is currently one of the most basic, common but important tasks for optometrists, so as far as the term optometry is concerned, it is familiar to both ophthalmologists and the general public in social life. Optometry is mainly to check the deformation of the eyeball, generally use two methods, one is to use the instrument to check, can initially measure the deformation of the eyeball, one is to use the lens to try to replace, with a pair of glasses with interchangeable lenses, to determine the need to wear glasses, so as to be able to match a pair of suitable glasses. All large optical stores use the above two methods of optometry. There are various methods of optometry, which can be categorized into dilated optometry and small-pupil optometry in terms of whether or not the eyeballs are allowed to regulate the stillness of the eyeballs. From the method of optometry, it can be divided into other sense of optometry and the main sense of optometry. In terms of optometry equipment, in addition to optometry lens box and shadow detectors and other conventional equipment, there are computerized optometry and comprehensive optometry. Computer optometry has been overly publicized, but through a large amount of information analysis, although the computer optometry is a high-tech crystallization, but it can only make a preliminary screening of refractive state, and can never be its results as the standard of optometry. Comprehensive optometry instrument set a variety of inspection functions in one, since the early 20th century, after the birth of the continuous improvement and development, it can not only check the refractive error of spherical lenses, but also correctly find out the astigmatism and astigmatism axial, in addition, but also on the eye position, adjustment and binocular monocular function to make a correct judgment, skilled grasp and the use of comprehensive optometry, is to improve the level of the key measures of optometry. From the medical point of view, the purpose of wearing corrective eyeglasses is not only to enable patients to see clearly, but also to make them comfortable in wearing the glasses and to treat certain possible eye diseases, such as visual fatigue, hidden internal or hidden external oblique, etc., and medical optometry is the foundation.