The black part of the eye is called the cornea, which is an important structure of the eye. The role of the cornea is very important: first, it maintains the integrity of the eye. Second, the cornea is part of the refractive media, and the cornea functions well so that the eye can see clearly. If any disease causes corneal lesions, such as keratitis, corneal ulcers, or corneal damage, it can cause pain, photophobia, tearing, foreign body sensation, burning sensation, and even loss of vision to varying degrees in the eye. Once these manifestations occur, early treatment is needed because inflammation of the cornea is usually very difficult to control, and if it is not treated promptly, once a corneal ulcer is formed, it will become very difficult to recover again. Therefore, it is important to detect and treat corneal lesions as early as possible to avoid serious effects on vision.