This mechanism is usually effective however the drying of the tear film can lead to small abrasions and allow external pathogens to infiltrate this privileged site, leading to a downward cascade of erosion and ulceration that can, if not managed, result in blindness.ĭiagnosing lagophthalmos in the primary care setting can be difficult as one must consider and eliminate the more sinister aetiologies of this condition. The eye elects to limit local immune and inflammatory responses to avoid scarring and preserve vision, this peculiarity is known as immune privilege, a phenomenon demonstrated by the cornea. The cornea is a multifunctional tissue it contributes a large proportion of the refractive power of the eye, meaning it must serve as a barrier to keep pathogens from reaching the rest of the eye, whilst maintaining transparency. With diminished ability to blink and close the eyelids, patients if not managed, are at high risk for exposure keratopathy, corneal surface breakdown, ulceration and ultimately permanent vision loss. The primary aetiology of lagophthalmos is facial nerve paralysis (paralytic lagophthalmos), however it can be resultant of surgical error, trauma (cicatricial lagophthalmos) or during sleep (nocturnal lagophthalmos).Īcute onset paralytic lagophthalmos due to facial nerve palsy is commonly seen in the primary care setting, ophthalmology practice and emergency department. Continued corneal exposure accelerates evaporation of the protective tear film and consequently patients complain of dry irritated eyes. Eyelid closure and the blink reflex are essential for a healthy corneal surface, maintaining ocular surface lubrication and also as protection from a foreign body in the event of an insult. Lagophthalmos is the incomplete or defective closure of the eyelids.
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