A pterygium is a growth, usually in the inner corner of the eye, which occurs quite commonly in Australia. It is related to sun exposure and exposure to dry dusty conditions. In the early stages it can often be treated with eye drops, as it often causes symptoms of irritation, redness and watering.
If it is causing recurrent irritation and the symptoms are unrelieved by drops, or it is a threat to the vision (because it is growing across the surface towards the pupil) then it may be necessary to surgically remove it. Often a graft of conjunctiva may be used to cover the defect and reduce risk of regrowth.