Normal naked eye visual acuity for adults is 1.0 or more when using a decimal scale; normal naked eye visual acuity for adults is 5.0 or more when using a logarithmic scale. Normal visual acuity varies with the age of the child. A 7-year-old child has a normal visual acuity of 1.0 or more; a 6-year-old child has a normal visual acuity of 0.8 to 1.0; a 5-year-old child has a normal visual acuity of 0.6 to 0.8; and a 4-year-old child has a normal visual acuity of 0.4 to 0.5. When the eye is not adjusted, parallel rays of light enter the eye and focus on the retina, which is the normal visual acuity of the naked eye. Children’s eyes are shorter in the developmental stage, and most of them are farsighted, called hyperopic reserve, which usually subsides around 9 years old. If you have any symptoms of eye discomfort, such as a feeling of vision loss, you should go to the ophthalmology department of the hospital and consult an ophthalmologist for guidance.