Visual acuity and refractive error are two completely different concepts and there is no conversion between them. The visual acuity test can only reflect the patient’s visual function, but not the refractive state and the number of refractive error. Therefore, a visual acuity of 4.8 cannot be inferred from a patient’s refractive error, just like telling a person’s height, but cannot be directly inferred from his or her weight. Visual acuity mainly reflects the visual function of the macular region, which is commonly measured by the clinical use of visual acuity table. Visual acuity 4.8 can only indicate that the patient’s visual acuity is lower than normal. There are many causes of poor visual acuity at different ages, mainly including refractive errors, such as myopia, hyperopia, astigmatism, etc. In addition, poor vision can also be caused by various factors such as corneal inflammation, corneal leukoplakia, cataract, macular degeneration, diabetes, retinopathy, etc. Therefore, vision 4.8 should be promptly seen to investigate the specific cause. If you want to know the specific degree of your eyes, you need to go to the ophthalmology department for an optometry examination, and at the same time combine with mirror inserts to try on in order to get the accurate degree.