A visual acuity of 5.1 falls within the normal visual acuity range and generally indicates that the patient has good vision. Normal adult visual acuity should be between 4.8-5.2 or 0.8-1.5. A visual acuity of 5.1 found at the time of examination indicates that the test result is normal. If the visual acuity is below 0.8 or 4.8, it is often necessary to use optometry to check the refractive state of the eye. However, the visual acuity test usually measures only the central visual acuity and cannot detect the presence of conditions such as visual field defects in the patient, so a normal test result does not guarantee that the patient is completely free of eye problems. If the visual acuity is 5.1 but accompanied by visual field defects, there may also be diseases such as glaucoma and retinal detachment. If there is no other abnormality in the eyes, you just need to pay attention to the use of eyes in general, avoiding long time playing cell phones, watching TV, ambulatory work and other close eye use, etc. If there is any abnormality, go to the ophthalmology department as soon as possible.