Visual acuity of 5.1 is a normal level, and the normal visual acuity of an average adult is 1.0 and above. Visual acuity of 5.1 is the result obtained through a visual acuity chart, which is usually checked during a medical examination, and the examination process mainly involves observing the chart. The smaller the words that can be seen on the vision chart, the better the patient’s vision. For people with a visual acuity of 5.1, the smallest words that can be seen at the top of the vision chart represent the better vision of the person being tested. In normal life, people should pay attention to scientific and hygienic eye use, so as to avoid myopia, etc., which will affect their eyesight. It is recommended that patients with abnormal vision should consult a doctor in a timely manner to assess their condition and follow the doctor’s instructions for treatment.