What cells populate the corneal stroma for repair and maintenance?

• A. Flattened fibroblast-like cells (keratinocytes)
• B. Melanocytes
• C. Endothelial cells
• D. Langerhans cells

Answer: (A)

The corneal stroma is maintained and repaired by keratocytes, which are flattened fibroblast-like cells nestled between the collagen lamellae. In a healthy cornea, these cells stay relatively quiescent, preserving the organized extracellular matrix that keeps the tissue transparent. When injury occurs, keratocytes activate and can become fibroblasts (and sometimes myofibroblasts), migrating to the wound and synthesizing new collagen and proteoglycans to restore the stroma. This makes the description of flattened fibroblast-like cells an accurate match for the cells involved in repair and maintenance.

Melanocytes are pigment cells not typically in the stroma; endothelial cells line the inner surface of the cornea and are involved in fluid regulation, not repairing stromal tissue; Langerhans cells are immune cells located mainly in the epithelium and anterior stroma, not the resident cells driving stromal repair.