Mydriatic optometry is mainly used to distinguish true and false myopia. In technical terms, mydriatic optometry relaxes the ciliary muscles of the eyes and removes the components of pseudomyopia through ciliary muscle paralysis. The diopter obtained in this state is the most true and accurate. Because cycloplegic agents are usually prescription drugs, this optometry method can only be carried out in hospitals, while optical shops often can only carry out obvious optometry, and the data obtained are not necessarily accurate. Glasses with inaccurate data often cannot be effectively corrected, which will lead to eye fatigue and even vision loss.

  In the lens part, three parameters need to be considered: refractive index, Abbe number and sphere.Generally speaking, the refractive index is: when the thickness of the center of the lens is the same, the higher the refractive index, the thinner the edge of the lens. In other words, the higher the refractive index, the thinner the lens. But this does not mean that we need to pursue high refractive index.