Lagophthalmos

LAGOPHTHALMOS, hare's eye (from Greek lagos, hare, and ophthalmos, eye), a condition in which the closure of the eyelids is either entirely impossible or possible only with very great effort, and even then not fully. The origin of lagophthalmos can be various. Not infrequently it is caused by mechanical reasons: congenital shortening of the eyelids, cicatricial ectropion of the eyelids (scars from burns, injuries, etc.), then marked protrusion of the eyeball due to an orbital tumor; furthermore, it occurs in severe forms of Graves' disease and prolonged unconsciousness in severely ill patients; most often, however, this symptom is of nervous origin. Lagophthalmos depending on a disease of the nervous system can be spastic and paralytic, functional and organic. Spastic lagophthalmos depends on a spasm of the levator palpebrae superioris muscle (the muscle that raises the upper eyelid), innervated by the oculomotor nerve. Paralytic lagophthalmos is most often of organic origin and is observed in peripheral facial nerve palsy. With complete facial nerve palsy, the eye does not close at all, but usually patients do not notice this at first, because at the moment of closing the palpebral fissures, the eyeballs deviate upward and outward, thanks to which the cornea hides behind the upper eyelid (Bell's phenomenon, see), the patient ceases to see and remains under the conviction that his eye is closed in the usual manner; he is usually disabused of this when washing: soapy water gets into the open eye and causes severe pain. Lagophthalmos is observed not only in peripheral facial nerve palsy, but also in supranuclear paralysis, in particular in asthenic bulbar palsy. Hysterical facial nerve palsy may also be accompanied by lagophthalmos; lagophthalmos of functional origin is observed not only in hysteria, but occasionally in other functional diseases as well; in these cases, lagophthalmos is less markedly expressed than in facial nerve palsy. Lagophthalmos, depending on the degree and duration of existence, is accompanied by symptoms of conjunctivitis, lacrimation, and sometimes damage to the cornea (keratitis ex lagophthalmo).--Therapy varies depending on the etiological factors. In mechanical lagophthalmos, it is often necessary to resort to surgical intervention (plastic surgery for cicatricial entropion, removal of orbital tumors, etc.); in peripheral facial nerve palsy, electrotherapy helps best, if treatment is unsuccessful, an operation of suturing the eyelids is used to prevent keratitis; in functional lagophthalmos, it is necessary to treat the underlying disease, etc.