Left eye 0.3 right eye 0.4 belongs to the level of vision, can not be based on the patient’s vision to determine whether the patient suffers from myopia, the specific reasons for the patient’s vision loss need to be examined in a professional organization to determine. If an adult’s vision is 0.3 in the left eye and 0.4 in the right eye, it is lower than normal vision and may be caused by a variety of eye diseases. Myopia is only one of them. In addition to myopia, there are many other factors such as cataracts, glaucoma, retinal detachment, etc. that can cause the patient’s vision to be lower than normal. In early childhood, low vision can also be caused by amblyopia and congenital eye diseases such as congenital cataracts. It is recommended that patients with visual abnormalities seek medical attention to evaluate their condition and follow the doctor’s instructions for treatment.