Exposure keratopathy is typically caused by CN VII palsy or orbicularis oculi dysfunction.

• A. True
• B. False
• C. Not related to CN VII
• D. Only in glaucomatous eyes

Answer: (A)

Exposure keratopathy happens when the cornea isn’t adequately protected by full eyelid closure and a stable tear film. The main defender of the cornea is the eyelid—not only sealing it shut during blinking but also spreading tears to keep the surface moist. When eyelids can’t close properly, such as with lagophthalmos, the corneal surface becomes exposed to air and evaporates, leading to dryness, epithelial breakdown, irritation, and potential ulcers.

The orbicularis oculi muscle, which is responsible for closing the eyelids, is controlled by the facial nerve (CN VII). If CN VII is palsied or the orbicularis oculi is dysfunctional, lid closure is incomplete. This protective mechanism failure directly cause exposure keratopathy, which is why this condition is typically caused by CN VII palsy or orbicularis oculi dysfunction.

Glaucoma, or conditions not involving lid closure, isn’t the primary driver of exposure keratopathy. While exposure keratopathy can occur in various settings (for example, with severe lid malposition or nocturnal lagophthalmos), the classic and most common link is impaired eyelid closure from CN VII or orbicularis dysfunction. Management focuses on protecting the cornea with lubrication and moisture retention, and in more severe cases, procedures to improve lid closure may be considered.