From a normal point of view, the best vision is 5.3, and both eyes are symmetrical, that is, you can see the last line of the E sight table. For special occupations, there will be higher requirements, such as pilots to check vision, will require the use of the C-word table, also to achieve the strongest discriminatory power. In addition, good vision also requires normal visual field, for example, some patients with glaucoma have good central vision but deficient peripheral visual field, the examination of vision may be normal, but not normal vision. A good visual status should require both binocular vision, fusion ability and stereopsis to be normal. Also, color vision and contrast sensitivity are in the normal range. Therefore, the examination of visual acuity includes not only central vision but also peripheral vision. At the same time, all the indicators related to vision are normal in order to be considered a healthy eye.