The normal visual acuity of an 8-year-old child should be 5.0 and above, and a visual acuity of 4.9 slightly below normal is usually abnormal, but it can still meet the requirements of normal life and study. Usually, the development of visual function of 8-year-old children is basically completed, that is to say, the normal visual acuity of 8-year-old children should be 5.0 and above, and at this time, the visual acuity of 8-year-old children is 4.9, which has not reached the normal value, so this degree is usually abnormal, belonging to the mild vision loss. If your 8-year-old child has a visual acuity of 4.9, you need to go to a regular hospital in time to improve your eye examination, such as visual acuity examination, slit lamp examination, fundus examination, etc., to clarify whether there are eye diseases and refractive errors. If the vision loss is caused by myopia, dilated pupil optometry should also be conducted. If it is caused by myopia, the child can wear appropriate glasses to correct myopia and improve vision. It is recommended that children with vision loss seek medical attention to evaluate their condition and follow the doctor’s instructions for treatment.