The cornea is the clear window at the front of the eye that allows light to enter. It is essential to maintain this structure for good vision. Because the cornea is less than 1 mm in thickness, it is very delicate and susceptible to damage. Occasionally surgery is necessary to repair the cornea. Some of the more common problems treated surgically are deep corneal ulcerations, corneal perforations, lacerations, corneal sequestrum, corneal/limbal tumors, and dermoids. These surgeries require equipment only used by ophthalmologist. These include an operating microscope as well as specialized suture material and instruments.