The Full Form of GPC is Giant Papillary Conjunctivitis.

Giant papillary conjunctivitis, commonly referred to as GPC, is a condition in which the inner lining of the eyelid (known as the palpebral conjunctiva) becomes inflamed and small bumps develop. These small bumps—known as papillae—often form in response to some type of chronic irritation, like wearing contact lenses. In GPC, the bumps grow and combine, forming very large bumps that sometimes resemble a cobblestone appearance. People with GPC complain of redness, whitish discharge, light sensitivity, and eye itching that is worse when they remove their contact lenses.