What type of keratitis is caused by dryness of the cornea?

Exposure keratitis occurs when the cornea becomes dry due to inadequate moisture, typically as a result of prolonged exposure or inability to adequately close the eyelids. This condition can arise from various factors, including facial nerve paralysis (which prevents eyelid closure), certain systemic conditions that affect tear production, or environmental influences that contribute to drying. The hallmark of exposure keratitis is the damage to the corneal epithelium, which is exacerbated by the lack of protective moisture.

The other types of keratitis mentioned are not directly related to dryness of the cornea. Ulcerative keratitis typically involves the development of corneal ulcers due to infection, while photokeratitis results from UV light exposure leading to inflammation. Contact lens-related keratitis occurs due to complications from wearing contact lenses, which can also disrupt the natural tear film but not primarily due to environmental dryness. Thus, exposure keratitis specifically highlights the role of dryness as a primary contributing factor.