There is no difference between a visual acuity of 1.0 and 5.0, they are two different expressions. Visual acuity, also known as visual acuity, is a very important indicator in eye examinations, representing the ability of the patient’s eyes to distinguish the details of a scene, and there are currently two mainstream methods of expression, namely, fractional and logarithmic. The decimal method defines normal visual acuity as 1.0, while vision loss is represented by different values ranging from 0.01 to 0.9, depending on the degree of loss. In logarithmic representation, normal visual acuity is defined as 5.0, and vision loss is expressed as 3.5 to 4.9 depending on the severity of the loss. If vision loss occurs and does not improve with rest, it is recommended to seek medical attention as soon as possible.