The eyelids are essential for keeping the eye moist and lubricated. They contain large oil glands (meibomian glands) which produce oil. Oil mixed with aqueous tears form a stable protective tear film over the eye. A tear duct drains excess tears from both lids to the back of the nose.
The upper lid may droop (ptosis) and obscure the vision or become elevated (retracted) giving a staring appearance. The lower lid can lose its natural elasticity, allowing the lids to role inward (entropion) or outward (ectropion). This causes the eye to become red, gritty and sore. The oil glands within the eyelid margins can become inflamed (blepharitis), causing a sore eye, or blocked resulting in a tender lid lump (Stye or Chalazion).
Lid lump (Stye, Chalazion, Carcinoma)
Blocked Tear Duct
Lid position (Ptosis, Retraction, Entropion & Ectropion)