The visual acuity of a 6-year-old child should reach about 0.8 to be considered normal, if the visual acuity is lower than 0.8, there may be refractive errors, amblyopia, etc.. 1. Refractive error: myopia, hyperopia or astigmatism are all refractive errors, which can cause vision lower than normal, this situation needs to be clearly diagnosed by an optometrist, and according to the specific circumstances of the choice to wear appropriate glasses to improve vision. 2. Amblyopia: 6-year-old children with amblyopia can also lead to vision loss, if there are congenital cataracts, corneal clouding, high myopia and so on can lead to amblyopia, 6-year-old children with amblyopia active treatment, it is possible to return to normal. If a 6-year-old child’s visual acuity is lower than 0.8, you should bring your child to the hospital in time, after a clear diagnosis and active treatment, so as not to affect the child’s eyesight.