Visual acuity is the most important indicator of the health of the eye. The development of visual acuity is a gradual process of improvement, so the standard of visual acuity is different in minors and adults. If you are an adult, you should normally have a bare eye vision of 1.0 or higher, which is a normal range of vision. In the case of children, because they are still relatively young, their vision has not yet developed to a normal level. Generally children around three years old have vision between 0.4-0.5, at the age of four they can reach about 0.6 and at the age of six their vision can reach 0.8, and at the age of eight they can develop into an adult state to reach 1.0, this is the normal range of vision. So if your eyesight is below the normal range, you must go to the hospital early to improve the relevant examination and give symptomatic treatment for the specific cause.