Normal visual acuity in adults is around 1.0 and is considered relatively normal as long as it is 1.0 as well as 1.0 or more. If it is slightly below 1.0, such as 0.8-1.0, it is also considered a relatively normal range of vision. If the visual acuity is significantly lower than 0.8 or if the quality of vision is significantly reduced when looking at something, this may indicate some abnormality in visual function or vision. If abnormalities exist, optometric treatment is required. If you use your eyes a lot, you can also have a dilated eye exam to get an approximate refractive error, and then you can have corrected vision based on the refractive error. If the corrected visual acuity does not reach about 1.0, there may be organic pathology of the eye, and a detailed examination from front to back is needed.