If the glasses are worn, it depends on the location and severity of the wear to decide if they need to be replaced. If the wear is only on the periphery of the lens and does not affect the central vision, you can continue to wear the lenses for a while until the degree of refractive error changes, such as an increase in myopia, and then replace the lenses. However, if the wear is very pronounced or in the center of the lens, it will affect the central vision and you will not be able to see clearly with glasses, so you need to replace the lenses as soon as possible, in order to maintain a clear visual quality in the eyes and avoid changes in the refractive error. Therefore, if the lenses are worn out, it is necessary to go to the hospital and have them examined by a doctor to decide if they need to be replaced.