A 13-year-old child with 400 degrees of astigmatism needs to undergo dilated optometry to determine the specific degree and axis of astigmatism, as well as corneal topography to rule out the possibility of cone cornea, which can then be corrected through the use of eyeglasses or rigid corneal contact lenses. Astigmatism is a common disease in ophthalmology, belonging to a type of refractive error, most of which develops in childhood. It is caused by the irregular shape of corneal development, and the curvature of the cornea is not the same vertically as horizontally, and the patient will have the symptom of blurring of seeing things. By doing astigmatism examination, we can obtain the exact degree of astigmatism in children as well as the astigmatism axis and other indicators, which will provide the basis for the subsequent treatment. For high astigmatism above 300 degrees, corneal topography must be done to exclude the possibility of cone cornea. Correction of astigmatism is mainly done by wearing frame glasses or using rigid corneal contact lenses, and for patients diagnosed with conical cornea, corneal cross-linking can also be done.