The cornea is the transparent outer layer of the eye, responsible for focusing light onto the retina. It acts as a protective barrier and plays a vital role in vision by directing light to the back of the eye. The cornea is made up of several layers, including the epithelium, stroma, and endothelium, each contributing to its function. Common issues that affect the cornea include conditions such as corneal abrasions, keratitis, corneal ulcers, refractive errors (e.g., astigmatism), and corneal dystrophies, which can lead to vision impairment if left untreated. The cornea's health is critical for maintaining clear vision and overall eye function.