It is important to dilate your child’s pupils before you order glasses because the ciliary muscle of your child’s eye is very elastic and has a very strong adjustment ability. If you don’t use dilating medication, the ciliary muscle will not be relaxed, and then there will be a lot of artifacts. Many parents worry that dilated pupils may cause harm to their children, but there is no harm in dilated pupils under the guidance of a doctor. The pupils may be temporarily inconvenient, and the child may experience blurred vision and photophobia during the period of pupil dilatation. Why do adolescents need dilated pupils? There are two purposes: First, the ciliary muscle of the adolescent’s eye is very elastic and has a very strong ability to adjust and converge, especially in children with refractive error, which can hide some of the adjustment and affect the accuracy of optometry if the pupil is not dilated. Second, dilated pupils provide a good examination of the fundus, especially in smaller, uncooperative children, to facilitate observation of organic lesions in the fundus. What are the possible consequences of not dilating the pupil? Optometry without dilating is basically overcorrection and very high prescription. Many children have strabismus or astigmatism problems that are not detected at all without dilated pupils, and their vision cannot be corrected in a timely manner by wearing appropriate glasses.