Abrasion to the epithelial layer of the cornea heals within 24-48 hours. Which layer is involved?

• A. Endothelium
• B. Epithelium
• C. Stroma
• D. Descemet's membrane

Answer: (B)

The outermost surface layer, the epithelium, is responsible for rapid corneal abrasion healing. When the epithelium is damaged, epithelial cells from the surrounding tissue and limbal stem cells rapidly migrate, proliferate, and re-cover the defect within about 24–48 hours, restoring the surface and barrier function. The inner layers don’t regenerate quickly in this scenario: the endothelium has limited regenerative capacity and primarily maintains corneal clarity through pumps; Descemet’s membrane is the basement membrane for the endothelium and isn’t the driver of this surface repair; the stroma heals slowly and can scar, affecting transparency.