A visual acuity of 4.7 usually requires eyeglasses. Adults should have a visual acuity of at least 4.9 to be considered as normal vision; the more common cause of vision loss is refractive error, including myopia, hyperopia, astigmatism and other reasons, the most common cause is myopia, patients usually need to wear glasses to correct their vision. Usually pay attention to daily maintenance, usually take more rest, to develop a good habit, avoid long time close work, learning, reading and writing posture to end, every day you can do eye exercises, relax the eye muscles, appropriate go out and look at the green plants, learn to use your eyes scientifically. It is recommended that patients with vision loss problems, go to the ophthalmology hospital for optometry, clear eyes are caused by refractive error, to determine the specific degree, with the appropriate glasses for correction.