Eyewear is a term used to refer to all devices worn over both of a person's eyes, or occasionally a single eye, for one or more of a variety of purposes. Though historically used for vision improvement and correction, eyewear has also evolved into eye protection, for fashion and aesthetic purposes, and starting in the late 20th century, computers and virtual reality. The primary intention of wearing eyewear can vary based on the need or desire of the wearer. Corrective lenses, such as glasses, contact lenses, and, historically, monocles are used to aid in one's vision and enable users to see clearly. Eyewear also can be used for protection, such as sunglasses which protect wearers from the Sun's ultraviolet rays which are damaging to the eyes when unprotected, eyepatches to protect injured eyes from further damage, or goggles which protect the wearer's eyes from debris, water and other chemicals.