Corneal Rings, also called "intacs" represent another recent development in the realm of vision correction. Corneal rings consist of two small plastic crescents or half circles which are placed, through very small incisions, in between the layers that make up the cornea. They then form an internal "ring" around the cornea. The idea is that the weight of the inserts is just enough to flatten out the curvature of the cornea's surface slightly. This changes the angle of light entering the eye and thus the point at which it focuses on the retinal screen.