Glasses are what you wear to help you see better if you have less than perfect eyesight. Some people need glasses to see far-away things, while others only use glasses for reading. And some people wear glasses just to look stylish or smart!
Most glasses have a stiff frame with prescription lenses inside. If your vision is less than 20/20 — if you have trouble reading what a teacher writes on a blackboard or find yourself holding your book very far away from your face to make out the words — you might need glasses. You can also call them "spectacles" or "eyeglasses," or if you only wear them to shield your eyes from the sun, "sunglasses."