Eye prescription is mainly used to correct the state of refractive error, if the prescription is not enough, the object is not able to normal, clear presentation on the retina, so see objects is blurred, for example, myopia in looking at objects need ciliary muscle contraction, adjustment, in order to see the object, if the prescription is not enough, the eye will have early fatigue state, if too long ciliary muscle is always in contraction, spasm state, can lead to If the ciliary muscle is in a state of contraction and spasm for a long time, it can lead to a prolongation of the eye axis and a gradual increase in the prescription, so it is recommended to have a regular vision check at least once every six months and to replace the glasses if the prescription grows. In addition, farsightedness requires presbyopic lenses to mediate when looking at near objects, and if the degree is not enough the ciliary muscle spasm in the eye is obvious and prolonged, patients may experience symptoms such as supraorbital neuralgia, headache, nausea and vomiting.