Keratitis resulting from drying of the cornea in the case of lagophthalmos.
Exposure keratitis is a relatively frequent clinical syndrome.For example, it may occur in association with facial paralysis following a stroke.
Due tofacial nerve palsy, there is insufficient closure of the eyelidsover the eyeball (lagophthalmos), and the inferior third to half of the cornea remains exposed and unprotected (exposure keratitis). Superficial punctate keratitis (see above) initially develops in this region and can progress to cor-neal erosion (see Fig. 18.5) or ulcer.
Other causes for exposure keratitis without facial nerve palsy include:
❖ Uncompensated exophthalmos in Graves’ disease.
❖Insufficient eyelid closure following eyelid surgery to correct ptosis.
❖Insufficient eye care in patients receiving artificial respiration on the intensive care ward.
Similar to superficial punctate keratitis (although usually moresevere) but unilateral.
Application of fluorescein dye will reveal a typical pattern of epithelial lesions (Fig. 5.11i).
Application of artificial tears is usually not sufficient where eye-lid motor function is impaired. In such cases, high-viscosity gels, ointmentpackings (for antibiotic protection), and a watch glass bandage are required.The watch glass bandage must be applied so as to create a moist airtight chamber that prevents further desiccation of the eye (see Fig. 2.9). In the pres-ence of persistent facial nerve palsy that shows no signs of remission, lateraltarsorrhaphy is the treatment of choice. The same applies to treatment ofexposure keratitis due to insufficient eyelid closure from other causes (see Etiology).
Poor corneal care in exposure keratitis can lead to superficial punctate keratitis, erosion, bacterial superinfection with corneal ulcer, and finally to corneal perforation.
This is one of the most frequent causes of superficial keratitis. The syndrome itself is attributable to dry eyes due to lack of tear fluid.