We all know that the purpose of optometry is to understand the refractive state of the eye, then to understand the accurate refractive state, you have to let the eye in the case of relaxed adjustment to examine. However, in children, the ciliary muscle paralyzing agent should be used during optometry to make the adjustment relaxed, and then to perform the examination of the shadow, so as to obtain more accurate refractive state results. While the ciliary muscle is paralyzed, the pupil is dilated, so this is commonly referred to as “dilated optometry”. The younger the child (less than 6 years old), the stronger the adjustment, and the stronger the ciliary muscle paralysis – 1% atropine ophthalmic ointment. (Number of doses: 3 times/day for 3 days, optometry on the fourth day, pupil dispersion for about 3 weeks). For older children (generally older than 6 years old) with weaker adjustment, a weaker ciliary muscle paralyzing agent, tropicamide, can be used (number of doses: every 5-10 minutes, 3-4 doses, 20 minutes after eye closure, pupil dispersion about 4-6 hours). However, for children with internal strabismus, the first optometry must be with atropine eye ointment, regardless of age.