If a three-week-old child’s vision is found to be 4.7, this is normal. Generally, a three-week-old child’s vision can reach about 4.8, a four-week-old should be able to reach about 4.9, and people over six years old should be able to reach a vision of more than 5.0. So depending on the age, the vision reference standard will be different. If you find that your vision is not normal, it is best to visit an eye clinic in time, and an optometry examination is usually required. For children and adolescents, a dilated optometry is necessary to initially determine whether refractive error is the cause, and also to rule out the possibility of amblyopia. There are other causes of vision loss, such as keratitis, glaucoma, uveitis, cataracts, or various fundus diseases. Therefore, when the diagnosis is clear, prompt and appropriate treatment should be carried out.