How common is pinguecula in the eyes? how many adults have it?

Super common: 20 - 90%. Risk increases with age and with alcohol use.

Very common: Pingueclua are a normal response to wind, dust and uv light. They are the eyes defense in the middle years to these external forces. They have no symptoms and are usually unnoticed. Almost all adults have them to some degree, although they can be so slight, that a microscope is need to see them. They are not present in childhood and fade in older age.