Ectropion is a condition in which the eyelid turns outward away from the eye and the conjunctiva is often exposed to varying degrees, often in combination with incomplete lid closure, more commonly in the lower lid than in the upper lid. In the milder cases, the posterior lip of the lid margin leaves the eye, and in the more severe cases, the conjunctiva is exposed and the eyelid closure is incomplete. Ectropion can be classified as scarring, paralytic, senile, or spastic depending on the cause of the ectropion. Chronic conjunctivitis occurs when the lid conjunctiva is exposed for a long time after ectropion, resulting in increased secretions and a dry, hypertrophic and congested conjunctiva. What is the differential diagnosis of bilateral lid ectropion? 1. Scarring lid ectropion is caused by extensive scarring of the eyelid skin, most often after eyelid trauma, inflammation, trauma or eyelid surgery. 2. Age-related lid ectropion is seen in the elderly. It is common in the lower lid because the orbicularis muscle is weakened and the eyelid skin and canthal ligaments are more lax, making the eyelid unable to press against the eyeball due to gravity. 3. Paralytic lid ectropion Because of facial nerve palsy, the orbicularis oculi muscle loses function and the pressure on the lid plate is weakened, and the eyelid is ectropioned by gravity, commonly in the lower lid. Lower lid ectropion can cause the tear dots to leave the lacrimal lake and cause tear overflow. In more severe cases, lid ectropion often has incomplete eyelid closure, leaving the cornea unprotected and the corneal epithelium dry and detached, which can easily cause exposure keratitis or ulcers. Generally, when performing corrective eye surgery prophylaxis, the orbital septum is first strengthened, the orbicularis oculi muscle is tightened, and finally the excess skin is removed. However, some doctors, wrongly consider the correction of eye bags as the lifting and tightening of skin, while ignoring the tightening of orbital septum and orbicularis oculi muscle. If the amount of skin removal is appropriate, but the orbital septum and orbicularis muscle are not treated, the bags will recur quickly. If too much skin is removed, the lower lid will become ectropion. In recent years, many scholars have agreed that the strengthening of the orbital septum and the tightening of the orbicularis oris muscle are more important than skin removal for the corrective surgery effect of under-eye bags.