Is it permissible to prescribe eyeglasses for patients despite knowing their harm, and that natural vision treatment may take years?

If the aforementioned harm concerning eyeglasses is true, it does not necessitate prohibiting their use or working in their field, because prohibition in Islamic law requires a certain or predominant and clear harm that leads to destruction or damage of an organ, and it does not include rare or minor harm. The general public uses eyeglasses without apparent harm. Natural methods can be explained to the patient, but there is no harm in selling eyeglasses.