The cornea is the clear, dome-shaped surface at the front of the eye that focuses light onto the retina. When it becomes cloudy, swollen, scarred, or misshapen from disease, injury, or infection, vision can become blurred, hazy, or distorted. Common causes include Fuchs’ dystrophy, keratoconus, infections, and trauma. Treatment ranges from medication and specialty contact lenses to corneal transplant surgery, depending on the severity and underlying cause.