Surgery is sometimes needed to correct a variety of problems associated with the eyelids. The most frequent causes of eyelid abnormalities requiring surgery include: entropion, ectropion, distichiasis, ectopic cilia, trichiasis, eyelid masses, lacerations, and prolapsed glands of the third eyelid. Many of these conditions, if left untreated, can cause chronic discomfort, corneal ulcerations or in extreme cases blindness.