Pterygia are non-cancerous growths that start on the white of the eye (sclera) and can invade the front of the eye (cornea). Untreated they can permanently disfigure the eye or cause discomfort and blurry vision.
People with mild pterygia may not have symptoms or need treatment, but large or growing pterygia can cause a red, gritty, itchy or burning eyes or the feeling that something is "in" the eye. If a pterygium significantly invades the cornea, it can distort the shape of the front surface of the eye, causing astigmatism and higher-order aberrations that affect vision. In this case, pterygium surgery to remove it may be necessary.