Lagophthalmos is defined as the inability to close the eyelids completely. The condition is frequently a result of a form of facial paralysis affecting the facial nerve (7th cranial nerve) which controls the eyelid’s closing muscle (orbicularis oculi). The paralysis, which can be permanent or transitory, arises from such causes as Bell’s palsy, trauma, stroke or can be surgically induced during the removal of certain types of tumors in close proximity to the facial nerve.
Lagophthalmos can be a serious condition. The ability of the eyelids to close and blink is crucial  to the distribution of the tear film necessary to maintain a healthy, lubricated eye. When the muscle that closes the eyelids becomes paralyzed, the  blink mechanism no longer functions and the eye becomes dry, painful and irritated. Prolonged  dehydration to the eye can lead to serious problems including a decrease in, or even loss of, vision.


Lagophthalmos can arise from a malfunction of the Facial nerve. Lagopthalmos can also occur in comatose patients having a decrease in orbicularis tone, in patients having palsy of the facial nerve (7th cranial nerve), and in people with severe skin disorders such as ichthyosis.
Today, lagophthalmos may arise after an overenthusiastic upper blepharoplasty. Blepharoplasty is an operation performed to remove excessive skin overlying the upper eyelid (suprapalpebral hooding) that often occurs with aging. This can appreciably improve the patient's appearance, and make the patient look younger. If, however, excessive skin is removed, the appearance is unnatural and "lagophthalmos" is one of the signs of such excessive skin removal.


Treatment of lagopthalmos can include both supportive care methods as well as surgical. If unable to receive surgery, artificial tears should be administered at least four times a day to the cornea to preserve the tear film. Leading up to a surgery, a patient can undergo a tarsorrhaphy which partially sews the eye shut temporarily to further protect the cornea as the patient waits for care. Multiple surgical treatments exist for Lagopthalmos but the most prevalent method includes weighing the upper eyelid down by surgically inserting a gold plate. Due to possible complications in conjunction with both the upper and lower eyelid, it might also be required to undergo a second surgery to tighten and elevate the lower eyelid to ensure both the upper and lower eyelids can fully close and protect the cornea.