To diagnose whether there is amblyopia or not, it is not enough to look at the abnormal performance of the child, but a professional examination of the eye is needed to make a clear diagnosis. Usually, depending on the age of the child, an appropriate way to do the initial vision examination will be chosen, such as different styles of vision charts, etc. In addition, the most important thing to diagnose amblyopia is to see if the child’s corrected visual acuity is lower than normal, and measuring corrected visual acuity requires dilating the child’s pupils before optometry. Many parents don’t understand, “Haven’t you already checked your child’s vision? Why do I need to dilate? The Internet says that there are different methods of dilating the pupils, so which method is better? Why do we need to dilate the pupils? The purpose of dilating the pupil is to paralyze the ciliary muscle and make the eye muscle fully relaxed so that the eye can be examined again to remove the interference of pseudomyopia and other factors and get the true refractive state of the eye. Because of the child’s low cooperation and the fact that if the pupil is not dilated during optometry, the regulation of the ciliary muscle is still present and may affect the accuracy of the results. For example, if a child has a normal vision test and the result is 0.1, and after dilating the pupil, it is found that he is actually 150 degrees nearsighted and his corrected vision is 1.0, he is not amblyopic, and if the child’s corrected vision is only 0.4, then he is amblyopic. A dilated eye exam is an important test to identify whether a child is amblyopic or has other vision problems. How is fast and slow dilatation done? How do I choose between the two types of astigmatism? There are two types of pupil dilatation: fast and slow. Slow dilatation paralyzes the ciliary muscles more fully and makes optometry more accurate for your child. Children under 12 years of age generally use slow dilatation, while children over 12 years of age can choose fast dilatation depending on the situation. Slow dilatation is usually done with atropine eye ointment, which is used two to three times a day for three consecutive days, with an optometric examination at the hospital on the fourth day. However, it takes about 21 days for the pupil to return to normal, during which time children are exhibiting difficulty reading at close range; in addition, during this period when the pupil is not recovered, they may exhibit photophobia when going out. For older children, in order to go to school and to make it easier to go out, you can choose fast dispersion, usually with tropicamide eye drops, once every five minutes on the day of the examination, and 20-40 minutes after the optometry after 6-8 consecutive times, and the pupil will recover on its own after 5-6 hours, which has less impact on life. It is worth noting that slow pupil dilatation is usually administered at home, and atropine ophthalmic ointment is an M-blocker, and very few children will have dilated blood vessels after using the medication, resulting in flushing or even fever. Therefore, parents are advised to regulate the use of the medication by applying only one drop at a time and then pressing at the tear sac (inner corner of the eye) to prevent the medication from being absorbed systemically through the nasolacrimal duct; in addition, drink more water after using the medication to promote metabolism so that the side effects of the medication can be minimized. As long as the medication is regulated, there will not be too serious reactions, and if symptoms appear, just stop the medication in time.