Often the amount of reserve hyperopia increases after dilation. Pupil dilation is a common test for children. By applying ciliary muscle paralyzing drops, such as atropine drops and compound tropicamide drops, the ciliary muscle and pupillary sphincter are paralyzed, thus restoring the eye to a fully relaxed state. Then, an optometric test is performed to obtain an accurate refractive error and to remove the error of the optometric test caused by the ciliary muscle spasms. After dilating the pupils, it will expose the hidden hyperopia, which will increase the patient’s reserve hyperopia. The most accurate hyperopia reserve number is the one obtained after dilated optometry, so when checking the hyperopia reserve number of the child, it is necessary to do dilated optometry, and the number obtained by ordinary undilated optometry is inaccurate. Usually, attention should be paid to scientific eye use, vision abnormalities, and timely medical examination.