Causes

• Allergies
• Blepharitis (eyelid inflammation)
• Chalazion (a type of cyst on your eyelid)
• Cluster headache
• Complication of eye surgery
• Contact lens problem
• Corneal abrasion (scratch): First aid
• Corneal herpetic infections (herpes)
• Dry eyes (decreased production of tears)
• Ectropion (outwardly turned eyelid)
• Entropion (inwardly turned eyelid)
• Eyelid infection
• Foreign object in the eye: First aid
• Glaucoma (group of conditions that damage the optic nerve)
• Injury, such as from a blunt trauma or burn
• Iritis (inflammation of the colored part of the eye)
• Keratitis (inflammation of the cornea)
• Optic neuritis (inflammation of the optic nerve)
• Pink eye (conjunctivitis)
• Scleritis (inflammation of the white part of the eye)
• Sty (a red, painful lump near the edge of your eyelid)
• Uveitis (inflammation of the middle layer of the eye)