The 5.1 inside the logarithmic visual acuity table is the international standard decimal point visual acuity table of 1.2, which belongs to the normal range of visual acuity, as long as greater than 5.0 is also greater than 1.0 visual acuity is the standard visual acuity, is not completely normal recommended to undergo an optometry. If it is a young person at 5.1 vision, it can be said that it is very standard vision. If it is a middle-aged or older person older than 45 years old, it is recommended to undergo an optometry, if the patient has presbyopia, his distance vision can also reach 5.1, but his near vision is not as good as it should be. The optometry can find out if the patient has other problems, and it is also recommended to ask the patient if there is high intraocular pressure or glaucoma. Patients with glaucoma have a late peripheral visual field that becomes a dark spot, only the middle visual field, and the central visual acuity can also reach 5.1, but the peripheral visual acuity is very poor, although it is rare, but it should also be asked to the patient.