Dermatochalasis is when there is too much skin on the eyelid, causing it to droop. Ptosis is when the eyelid is droopy. When the upper eyelids become so droopy that they block vision, surgical repair is covered under medical insurance. Correction of mild upper lid droopiness is considered a cosmetic procedure that is not covered by insurance.
Dermatochalasis is corrected by blepharoplasty, a surgical procedure in which the extra skin and muscle of the eyelid is simply excised and sewn back together. The incision is made such that the resulting scar is hidden in the upper eyelid crease. Ptosis that does not have coexisting dermatochalasis can be repaired with a procedure called a mullerectomy, in which the upper eyelids are flipped over and the muscle on the underside of the lid is shortened by excision. This procedure only works well for patients with mild ptosis.
When the lower eyelid is not positioned correctly, it cannot protect the eyeball, which leads to chronic eye redness, irritation, and discharge. Eyelids that are turned out are called ectropions; eyelids that are turned in are called entropions. Mild cases can be symptomatically managed with aggressive lubrication using over-the-counter artificial tear products and ointments. More severe cases require reconstructive surgery.