Eyelids are thin folds of skin that cover and protect the eyes. They help keep the eyes moist by spreading tears across the surface and prevent foreign objects from entering. Eyelids also play a crucial role in regulating light exposure, allowing us to blink and close our eyes when needed. Each eyelid consists of several layers, including skin, muscle, and connective tissue. The upper eyelid is typically larger and more mobile than the lower eyelid. Eyelids contain small glands that produce oils to maintain eye health and prevent dryness, contributing to overall vision quality.