Alessandro di Spina is credited with inventing glasses in 1280 by many. It is more accurate to credit him with introducing glasses to Italy rather than inventing them.
Glasses can NOT hurt your eyes if you are an adult. They may in children. In adults, wearing glasses will not cause any permanent changes to the eye. Children with developing vision should not wear glasses that are not prescribed to correct an individual vision problem.
Glasses can cause headaches in people who wear them for several different reasons. Most headaches that are caused from wearing glasses are due to eyestrain.
Glasses and contact prescriptions are NOT the same. Not only does the power change slightly between prescriptions, but contact lens prescriptions require several measurements that glasses do not.
Glasses correct vision by taking into consideration the curvature of the eye, the thickness of the eye, and the index of refraction. The glass is cut accordingly to correct each of these.
In some cases, glasses will fix a lazy eye. Sometimes a pair of glasses is all that is needed for a mild case; usually, however, there is more to the treatment than this.
Glasses can NOT correct vision. Glasses will correct sight and vision while wearing them, but do not correct the cause of vision problems. As a result, taking off the glasses will result in the same nearsightedness or farsightedness that caused a prescription for glasses.