Pterygium is caused by frequent outings, stimulation by ultraviolet rays or various kinds of light, and lack of corneal limbal stem cells, which leads to the growth of pterygium into the cornea. With eye drops there are no effective eye drops, mainly hormonal or non-steroidal eye drops are used to temporarily control the congestion of the pterygium because if the pterygium is congested and rich in blood vessels, the pterygium grows faster. If the color of the pterygium is redder than that of the pterygium, you can use temporary eye drops such as Dilbesol eye drops, Flumethasone eye drops, or Pralofen eye drops to temporarily control inflammation and reduce the congestion of the pterygium so as to slow down the growth of the pterygium. The most important thing is to avoid external stimuli, for example, high altitude areas are rich in ultraviolet rays, must wear sunglasses to avoid ultraviolet radiation. If the pterygium grows large enough to enter the cornea and affect the vision, it is best to have surgery.