Pterygium is a common ocular surface disease that most often occurs in middle-aged and elderly people. The cause of the disease is still not fully understood, with ultraviolet light being one of the clear causative factors. Pterygium develops slowly and many people do not pay much attention to it until it grows into the cornea and obscures the pupil before they come to the doctor. In fact, pterygium causes a number of ocular and refractive problems before it affects vision, leading to: increased astigmatism, tearing, dryness, eye redness, and foreign body sensation, so it is recommended that surgery be considered to remove the pterygium if it grows into the cornea more than 2 mm. In the early stages of pterygium, the lesion only reaches the anterior elastic layer of the cornea, so the cornea can be left unscarred after surgery. However, over time, the lesion breaks through the anterior elastic layer and reaches the stromal layer, accompanied by a series of stromal degeneration, often leaving a faint corneal scar after surgery. Therefore, keratologists recommend that you do not delay your pterygium surgery for the sake of your eye health.