Lower eyelid redness and swelling is a common ocular condition that can be caused by a variety of factors, such as eye trauma, where the eyelid is struck by an external force, which can cause local contusions to the eyelid; inflammatory reactions in the conjunctiva and eyelid due to various factors, which can cause eyelid redness and swelling; blephar gland cysts due to blephar gland obstruction, which can cause eyelid redness and swelling if not treated in a timely manner; and diseases of the lacrimal system, such as acute lacrimal sacculitis. Acute dacryocystitis, for example, can cause redness and swelling of the lower eyelid if the inflammation is not controlled in time, especially in infants and young children, and acute dacryocystitis can cause redness and swelling of the lower eyelid. Some ophthalmic surgeries can cause lower eyelid redness and swelling, such as lid entropion, lid ectropion, and postoperative reactions after eye bag removal surgery can cause lower eyelid redness and swelling. In addition to disease factors, some non-disease factors can also cause lower eyelid redness and swelling, such as foreign bodies entering the eye, rubbing the eye, not paying attention to rest and staying up late, all of these factors can cause lower eyelid redness and swelling. To sum up, there are more factors that cause lower eyelid redness, which are roughly divided into those caused by disease factors and those caused by non-disease factors.