Glasses only correct a refractive error and will help you see well if you are wearing them. For example, a vision of 20/70 to 20/160 can be improved by special lenses for clearer vision. Once you remove them, the symptoms that led to wearing the glasses return, such as headaches, agitation, or tired eyes for farsighted people. Glasses are designed to correct your vision to 20/20 or better based on your existing prescription and not treat the cause. For instance, nearsightedness is caused by a slightly longer eyeball than is expected or by a steeply curved cornea. Thus, it is best to wear your glasses as directed by your eye care provider. However, certain conditions necessitate wearing glasses, and vision will improve once they have been addressed. Additionally, refractive surgery can help to improve your vision permanently.