The cornea is a transparent layer that covers the front of the eye. Not only does it keep external particles away from the eye, it also acts as a “window” that controls the light entering the eye. The cornea possesses the ability to change shape and contributes to the positioning of light rays that enter the retina. These light rays are then translated into impulses which are processed and interpreted as images by the brain.
The cornea may stiffen and lose the ability to change shape as we grow older. Since this condition prevents light from focusing on the retina, a person affected will experience a refractive error that leads to poor vision. A refractive error is classified into three: myopia or nearsightedness, hyperopia or farsightedness, and astigmatism, which makes all objects at any distance appear blurry or distorted in the eyes of the affected individual.
A common method to correct a refractive error is to wear prescription glasses or contact lenses daily or whenever necessary. They can bend the light entering the eyes and properly focus it onto the retina. A more permanent way to correct refractive errors is through LASIK eye surgery, a procedure that involves an excimer laser that permanently reshapes the cornea.