The human cornea is one of the fastest-healing tissues in the body, often repairing minor scratches within 24 to 48 hours.

The cornea is the transparent front part of the eye that covers the iris and pupil. It consists of five distinct layers, with the outermost layer known as the corneal epithelium. This layer is composed of highly specialized cells that possess an extraordinary rate of turnover and regeneration.When a minor abrasion occurs, such as a scratch from a fingernail or a dust particle, the surrounding epithelial cells begin to migrate to the site of the injury within minutes. According to studies published in the Journal of Ophthalmology, these cells can move at a rate of approximately 60 to 80 micrometers per hour to seal the wound. This rapid response prevents infection and restores the eye's protective barrier.Unlike most tissues, the cornea is avascular, meaning it contains no blood vessels. Instead, it receives nutrients through the aqueous humor and tears, while absorbing oxygen directly from the atmosphere. This unique lack of blood vessels is essential for maintaining optical clarity, as blood would block or scatter light entering the eye.The healing process is further supported by a high density of nerve endings, making the cornea one of the most sensitive parts of the body. This sensitivity triggers the blink reflex and tear production, which helps flush out debris and provides the moisture necessary for cell migration. Most superficial corneal abrasions resolve completely within two days without leaving any permanent scars.