Normal people over the age of six should be able to achieve a visual acuity of 5.0 or more. A naked eye visual acuity of 4.6 is abnormal and requires a routine examination at an eye clinic. Most patients consider refractive errors caused by refractive errors, such as myopia, hyperopia and astigmatism, as long as they wear glasses. Corrected visual acuity can be above 5.0 without any treatment, only need to wear glasses to correct. Some patients may have keratitis, glaucoma, uveitis, cataracts, or even retinopathy of the eye. If the cause is clearly identified, we should treat the symptoms. If the cause is cataract, we can consider cataract ultra-emulsion and IOL surgery to improve the vision.