KRT3, or Keratin 3, is a type of protein that is part of the keratin family. It is primarily found in the corneal epithelium of the eye, where it plays a crucial role in maintaining the structure and function of the cornea. Keratins are essential for the integrity of epithelial tissues, providing strength and protection. Mutations in the KRT3 gene can lead to various eye disorders, including Meesmann epithelial corneal dystrophy. This condition is characterized by the formation of small, clear cysts in the corneal epithelium, which can affect vision. Understanding KRT3 is important for research into corneal health and related diseases.