The Castroviejo Lecture. Prolonged eyelid closure is a risk to the cornea.

PURPOSE: The author introduces new concepts and summarizes published evidence suggesting that prolonged eyelid closure puts the cornea at risk.

METHODS: Significant clinical and experimental publications are reviewed, and the author's experience is applied relating to the pathogenesis and treatment of a variety of clinical entities thought to be induced, to some degree, by prolonged eyelid closure.

RESULTS: Evidence from the scientific literature suggests that the hypoxia or reduced tear volume or both that result after prolonged eyelid closure, especially during sleep and when a soft contact lens is in place, serve as risk factors in the "sucked-on" contact lens syndrome, recurrent corneal erosion, chronic corneal deepithelialization, Pseudomonas keratitis, filamentary keratitis, superior limbic keratoconjunctivitis, sterile midperipheral corneal infiltrates, and corneal vascularization. The limbal stem cells under the upper eyelid are subjected to continuous hypoxic stress and are at special risk to other insults.

CONCLUSIONS: Prolonged eyelid closure, such as in patching and in sleep, is a risk factor in the pathogenesis of a variety of corneal conditions.