Whether or not a visual acuity of 4.9 is myopia needs to be determined in conjunction with the results of a dilated eye exam. If an adult has a visual acuity of 4.9, he or she may be myopic, while a child with a visual acuity of 4.9 before the age of 8 cannot be considered myopic. Normal adult naked eye vision is generally above 5.0. 4.9 is low compared to normal vision and may be considered mild myopia, requiring an eye examination at a hospital to rule out other diseases that cause vision loss. Children’s visual acuity is still incomplete due to development, and can generally reach 4.5-4.7 at age 3, 4.6-4.8 at age 4, 4.7-4.9 at age 5, and 4.9-5.0 at age 6, but after the age of 8, children’s visual acuity should be higher than 5.0, and 4.9 before the age of 8 can be considered normal. Therefore, if a child before the age of 8 has a visual acuity of 4.9, parents can pay attention to it; if a child above the age of 8 still has a visual acuity of 4.9, he or she may be myopic and needs to take the child to an ophthalmologist for a dilated eye exam and true myopia requires eye wear.