A visual acuity of 1.0 is considered normal for adults. China’s visual acuity table design with 1.0 on behalf of the normal naked eye vision, eye vision how much varies from person to person, the visual acuity value at the same time will also be different, good eyesight of the people for vision testing, there can be up to 1.2, 1.5, or even 2.0, such naked eye vision is better than the average person, but should also pay attention to the prevention of myopia. Refractive error causes a decrease in naked eye vision. If the naked eye vision of both eyes reaches 0.8 or above and has no adverse effect on one’s life and study, one may not need to wear glasses, but one should pay attention to developing good eye habits and undergo regular checkups. If farsightedness, astigmatism or myopia causes a decrease in naked eye vision, it is recommended that correction be made so that vision can be restored. If there is a decrease in vision in the eyes, you should go to the hospital for optometry and examination under the guidance of a professional doctor to find out the cause and then correct or treat the problem.