Visual acuity refers to how far away objects can be seen under the premise of 1 point of view, regardless of the fractional visual acuity scale, decimal visual acuity scale, and logarithmic visual acuity scale are all made according to this principle, and generally classify the ability to see 1.0 (5.0 on the decimal visual acuity scale, i.e. logarithmic visual acuity scale) under 1 point of view as normal visual acuity. Each person has a different minimum visual quotient, which is based on the density of each person’s retinal cone cells. When the density is greater, the visual quotient is higher and the minimum visual angle is smaller, so that 3.0 (on the fractional visual acuity scale) or even higher visual acuity exists. Therefore visual acuity is not equivalent to refraction. Visual acuity has fractional recording method, decimal recording method, logarithmic recording method, domestic mainly use decimal and logarithmic recording, they are convertible, V log = 5 + lgV decimal, for example, 1.0 with logarithmic recording is 5 + lg1 = 5.0. Because each person’s visual quotient is different, so normal visual acuity national standard requirements, monocular 1.0 (5.0) or more. In general, normal bare vision can reach 1.0, or 5.0. people with refractive error (myopia, hyperopia, astigmatism), bare vision will be lower than normal, but can be corrected to normal vision of 1.0 (5.0) after wearing glasses. If the corrected vision through glasses is still below normal, a thorough eye exam is needed to see if the eye has other diseases. If the corrected visual acuity of the eye is below normal and the eye exam reveals everything is normal, it is likely that there is amblyopia. Amblyopia needs to be treated before the age of 6 to be more effective, and if you are an adult, there is little treatment for amblyopia. For eyes with simple refractive error, if myopia correction surgery (including excimer laser surgery and intraocular lens surgery) is applied, the post-operative vision should be able to reach normal vision. If there is an accompanying amblyopia, it will still be difficult to achieve normal vision after surgery. However, vision screening is a subjective test and there are a number of other factors that can affect the results. Common factors that affect the accuracy of the vision test are: 1, light: old light box, light source brightness is not up to standard, panel scratching, dim light around the test site, etc.; 2, environment: the surrounding environment is noisy, noisy, etc.; 3, mood: poor mood can also affect the results; 4, health: if during a cold, fever or medication, vision may also decline. To protect the health of your eyes, you should go to the hospital for a comprehensive formal examination for any condition that causes vision loss. For refractive errors, you should choose the appropriate correction method to obtain normal vision and ensure a normal quality of life. Methods of correcting refractive errors include: frame glasses, contact lenses, refractive surgery, etc. The appropriate method can be chosen according to each individual’s specific situation and under the guidance of a professional doctor.