We often see some children go to the hospital for checkups, and after finding bad eyesight, doctors suggest dilated pupils for optometry, that is, the application of drugs (1% atropine ophthalmic ointment for children under 12 years old, and compounded tropine amide ophthalmic solution for those over 12 years old) to paralyze the ciliary muscle in the eye, dilate the pupil, and perform optometry with no regulation. Children and adolescents have strong eye regulation, so when children with myopia look at things, they always like to put the things they look at closer, and the more myopia they have, the closer they put them. The closer something is to the eye, the more the eye regulation has to be strengthened, when the ciliary muscle is highly and continuously contracted, the excessive use of regulation makes the lens more convex, the refractive power is enhanced, leading to myopia deepening, in this degree actually contains the components of pseudomyopia. Therefore, myopia in adolescents, with pseudomyopia caused by poor use of the eye, is mixed with pseudomyopia even in true axial myopic eyes, so the results of optometry with accommodation are very inaccurate, often leading to a greater degree of optometry than the actual lens that should be worn, which can cause damage to the eyes of children. The pupil dilatation is more objective and more accurate because it eliminates the interference of the adjustment and avoids over-adjustment of the ciliary muscle or relaxation of the adjustment spasm in children, avoiding pseudomyopia or astigmatism caused by the adjustment spasm. At the same time, it also has a therapeutic effect on pseudomyopia. The pupils are dilated to facilitate the retinal examination and the prescription is more accurate. For example, in children with hyperopia, because of the short eye axis, in order to see near objects, it is necessary to use the adjustment force, and even to see far, it is necessary to use the adjustment force of the eye, in order to see the outside world at any distance, it is necessary to contract the ciliary muscle to enhance the refractive power. If the ciliary muscle is not paralyzed with medication, the regulation will mask some of the farsightedness and prevent it from being detected. The younger you are, the stronger the accommodation, and the higher the degree of masking. If the ciliary muscle is not paralyzed by dilating the pupil, it will not be possible to detect all the degrees that are actually present. For children with poor vision and farsightedness requiring glasses, the main goal is to correct visual acuity to prevent refractive amblyopia, and to correct eye position (most farsightedness is internal strabismus) to prevent strabismic amblyopia. All of this requires that the exact number of degrees be checked, so optometry for children must be performed after the pupils are dilated. The dilated pupil not only facilitates the operation of retinal examination (optometry), but also facilitates fundus examination to identify the nature of eye gaze and fundus photography, which helps to exclude other fundus diseases.