Pingecula/Pterygia
A pterygia is a pinguecula that has grown onto the cornea.
Most pingueculas do not grow onto the cornea. Pinguecula and pterygia are mostly cosmetic concerns and do not represent cancers. Pterygia are surgically removed if they get too close to the center of the cornea. However, they can be a significant cosmetic concern and are frequently removed for this reason. (The picture shows the preference of most Pterygia to grow on the nose side of the cornea. The cornea is over the iris or the colored part of the eye. Notice that Pterygia occur between the two eyelids, where wind and dust hit the eye. This is why we think that exposure to the elements is the major reason why Pterygia occur).
Pinguecula and pterygia are more common in people that live by the equator so exposure to sunlight is also thought to be a major risk factor in their development. Exposure to dust and wind are probably also risk factors. Wearing sunglasses and lubricating the eyes with artificial tears, not Visine, may slow their progression and make them less noticeable.
Surgically, pterygia are easily removed from the cornea and the sclera since they are attached superficially. The major risk of surgery has been the chance of recurrence after removal. After surgery, they can grow back even more aggressively than they were before surgery. Recent techniques involving a rotational graft and/or anti-metabolites have reduced the incidence of regrowth after removal. I offer an advanced, in-office Pterygia removal service involving the latest rotational grafts.
Concretions
Concretions are collections of calcium in the conjunctiva. (The conjunctiva is the skin lining the inside of the eyelids and the outside of the eyeball, forming a sac). They become symptomatic when they erode through the conjunctival surface, typically in the upper eyelid, and rub against your cornea each time you blink. They are usually few in number but I have seen cases where 50-75 concretions formed a continuous line along the upper tarsal border of the upper lid. A symptomatic concretion will eventually have the conjunctiva regrow over it with the symptoms going away, although the concretion can be de-roofed again.
Concretions are not related to high blood calcium levels.