Visual acuity has a distant visual acuity (look at the distance of vision, usually check the distance of 5 meters) and near vision (look at the near vision, usually check the distance of 30 cm). According to the results of the examination of distance and near vision, the eye condition can be roughly judged: if the distance vision is abnormal, but the near vision is normal, it is mostly myopia or myopic astigmatism; if the distance vision is normal, but the near vision is abnormal, it is mostly moderate hyperopia or hyperopic astigmatism; there is also a situation where both distance vision and near vision are abnormal, it may be high hyperopia and hyperopic astigmatism, or it may be eye diseases such as congenital cataract, Congenital glaucoma, fundus disease, etc. Once poor vision is detected, children should go to the hospital for further examination, such as slit lamp microscopy, fundoscopy, intraocular pressure and dilated eye examinations, to determine the cause of poor vision, whether it is due to refractive error (farsightedness, myopia, astigmatism) or eye disease. In this way, appropriate treatment can be provided based on the test results. Most eye diseases can be treated well if they are detected and treated early. On the contrary, if the treatment is delayed and the critical period of children’s vision development is missed, even if the eye disease is well treated later, the vision will not be well improved, thus affecting the future life, study and work.