A 10-year-old child who can see 4.9 on a visual acuity chart indicates mild vision loss and needs to be seen to find out the cause before deciding whether or not to wear glasses under the guidance of a doctor. If the vision loss is caused by refractive error, glasses should be worn when it affects normal vision. Under normal circumstances, a 10-year-old child’s visual acuity should reach 5.0, but the current visual acuity of only 4.9 is slightly below normal, indicating that there is a mild loss of vision, and you need to find out what the cause is. If it is caused by refractive error, such as myopia, hyperopia, astigmatism, etc. caused by vision loss, affecting normal vision, should be corrected by wearing glasses, otherwise it is easy to see clearly and attention fatigue, and may lead to refractive error degree increase. If the vision loss is caused by non-refractive factors, such as fundus lesions, cataracts, etc., wearing glasses is ineffective, and different measures need to be taken to deal with it. When vision loss is detected on the visual acuity chart, further tests, such as optometry, are needed to determine whether glasses are needed.