Vision of 0.5 in a 6 year old child is mostly abnormal, as a general rule, children basically develop their vision to about 0.8-1.0 by the time they are about 6 years old. Children start with low vision at birth and gradually improve their vision as their vision develops. By the time children are 6 years old, their vision will have mostly developed to about 0.8-1.0. If a 6 year old child has a visual acuity of only 0.5, the visual acuity is below that of his or her peers and is considered abnormal. The child needs to go to the ophthalmology department of the hospital in time for a detailed examination to clarify the cause of low vision. Common clinical causes of low vision include refractive errors, congenital cataracts, amblyopia and other eye diseases, which need to be treated promptly to improve vision. Children with vision loss are advised to seek prompt medical attention to assess their condition and follow the doctor’s instructions.