👉 Pterygiums, also known as palpebral pseudocystic keratosis (PPCK), are a type of skin condition that occurs mainly on the eyelid and the cornea. They are characterized by the formation of small pink or purple scaly patches on the eyelid and around the corners of the eye that may cause discomfort, irritation, and sometimes even pain. Pterygiums can be caused by various factors such as UV exposure, hormonal changes, stress, or certain