Optical glasses, also known as eyeglasses or spectacles, are a type of corrective LENSES used to improve vision. They consist of two LENSES made of optical glass, which are held in place by frames that sit on the bridge of the nose and behind the ears. The LENSES are designed to refract light in order to correct refractive errors in the eye, such as nearsightedness, farsightedness, and astigmatism. Optical glasses can also be used for protection from the sun's ultraviolet rays, and for reading and computer work.