Eyeglasses are the most common form of eyewear used to correct or improve many types of vision problems. They consist of a frame that holds 2 pieces of glass or spectacle frame to correct refractive errors.
Sunglasses or sun glasses (informally called shades or sunnies) are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes.
Transition Lenses are eyeglass lenses that will turn dark (resembling sunglasses) in sunlight and become clear again when indoors. This is the result of chemical responses to the presence (and absence) of ultraviolet light (Sun Light).
Computer glasses with an anti-glare coating usually have a thin layer that can block reflections and increase visibility. This helps you see the screen more clearly, and reduces eye strain by quite a bit.
Glare can also cause eye strain and headaches, but computer glasses are capable of protecting you from both.
Contact lenses are thin, clear plastic disks you wear in your eye to improve your vision. Contacts float on the tear film that covers your cornea. Like eyeglasses, contact lenses correct vision problems caused by refractive errors.