4.5 visual acuity is the visual acuity recorded using the visual acuity 5-point recording method, which corresponds to a visual acuity of 0.3 in the decimal recording method, and such visual acuity is abnormal. Visual acuity refers to the ability of the retina to distinguish images, and there are various ways to express visual acuity, among which the visual acuity recorded by the 5-point recording method and the decimal recording method can be converted. For example, 4.5 visual acuity is the visual acuity recorded by the 5-point recording method of visual acuity, which corresponds to a visual acuity of 0.3 in the decimal recording method. The detailed relationship between the two is 5.2 corresponds to 1.5, 5.1 corresponds to 1.2, 5.0 corresponds to 1.0, 4.9 corresponds to 0.8, 4.8 corresponds to 0.6, 4.7 corresponds to 0.5, 4.6 corresponds to 0.4, and 4.5 corresponds to 0.3. A vision of 0.3 is lower than the normal value, and a normal adult patient’s visual acuity is 1.0 and above. Patients with vision loss are advised to seek prompt medical attention to evaluate their condition and follow the doctor’s instructions for treatment.