What is the best drop for pterygium?

Tear drops. There is no eyedrop which specifically will treat pterygium. Ordinary tear replacement drops may cause some improvement in symptoms if you have them, but will not directly treat the pterygium. The only effective treatment is surgical excision.
Pterygium drop. No single drop has shown to be superior for the treatment of pterygium. Lubricating eye drops over the counter, low dose anti-inflammatory drops, restasis, over the counter vasoconstrictor drops can all be utilized effectively.
Lubrication Steroids. Lubrication drops and mild steroids can help with a pterygium and associated inflammation. Usually treatment eventually requires surgical removal and is done in the operating room. Also, there is always the small possibility of recurrence of the pterygium.
Pterygium. Prevention is key remedy. Avoid sun (sunglasses, hat); avoid smoking. Naphcon-A®, Naphcon Forte® help temporarily; Natural rx info: see eyedoc2020.blogspot. Com; Other ways to help decrease symptoms: cold artificial tears, nsaid drops, low dose or hi dose steroids (though risk of glaucoma, cataract); surgery is only real way to remove/cure: though 5-15% risk of recurrence. Best of luck.
Pterygium. A pterygium is a condition when the conjunctiva (the clear skin coating of the white of the eye) grows over the cornea (the clear part overlying the colored iris). If it spreads near or over the visual axis, vision can be compromised. There is no cure, aggressive lubrication and avoidance of uv light (sun rays) can possibly keep it from progressing. Surgical removal with graft is only tx.