Refractive error in a 6 year old child means that the child has an abnormal refractive status, i.e. the presence of myopia, hyperopia or astigmatism. Refractive error is characterized by the inability of parallel light rays from the outside world to focus on the retina after passing through the refractive medium of the eye, thus failing to form a clear image. If it focuses in front of the retina, it is myopia; if it focuses behind the retina, it is hyperopia; and if it forms two lines of focus and cannot form a focal point on the retina, it is astigmatism. Once children are found to have refractive errors, it is recommended to go to the ophthalmology department of the hospital for a comprehensive examination in a timely manner. If necessary, it is necessary to carry out a dilated optometry examination to accurately determine the type of refractive error as well as the refractive error degree, and in conjunction with the actual situation, to consider whether it is necessary to wear the appropriate glasses to correct the visual acuity.