50 degrees before dilation and 150 degrees after dilation is often seen in ophthalmology in children with hyperopia. The effect of dilation is to paralyze the ciliary muscle of the eye. When the ciliary muscle is in a relaxed state, it loses its ability to regulate, and then the corresponding refractive error masked by the regulation of the ciliary muscle will be fully exposed. Therefore, in hyperopic children, the refractive error after dilation is often higher than the refractive error before dilation. The younger the child, the greater the difference may be, because the younger the child, the greater the ability of the ciliary muscles to regulate. For this reason, the eyes need to be fully dilated before a hyperopic child is prescribed a prescription. The refractive error after dilation is used as the standard for spectacle fitting.