Whenever we meet parents with their children who have been examined for bad eyesight, but have refractive abnormalities, they refuse to have their eyes dilated and have to be convinced to do so. Parents believe that dilated pupils hurt their eyes and that their children are uncomfortable. In children under 12 years old with poor vision, after eye diseases have been ruled out, refractive examinations, or medical optometry, must be done with dilated pupils. Why? Because children’s eyes are highly regulated, and without dilated pupils, optometry is inaccurate and may treat pseudomyopia as true myopia and overcorrect myopic eyes, and farsightedness will be under-checked, or farsightedness will be treated as myopia. In fact, after the pupil dilatation, the eye will only appear to see near vision blurred, photophobic symptoms, will not damage the eye, the general principle is that those without internal strabismus, you can short-acting drugs to dilate the pupil, that is, rapid dispersion, such as tropicamide drops, after using 4 hours to recover. If you have internal strabismus, you must use long-acting medication, such as atropine, to fully dilate the pupil and get an accurate optometry. Recovery is usually two weeks. Also, a review should be done every six months, up to a year, and where under 12 years old, the pupil should be dilated each time. Therefore, children under 12 years old, due to poor vision, refractive correction, must go to the hospital ophthalmology, medical optometry, including dilated pupil optometry, in order to get the correct correction.