What does a chalazion affect?

A chalazion specifically affects the eyelid. It is a common condition characterized by the formation of a firm, painless lump in the eyelid due to the obstruction of a meibomian gland, which is responsible for producing the oily component of tears that helps lubricate the eye. This blockage leads to inflammation and the formation of a cyst. While the other structures listed, such as the retina, conjunctiva, and iris, are crucial components of the eye, they are not directly associated with the development or effects of a chalazion. Instead, the chalazion presents itself distinctly on the eyelid, making this the correct focus for understanding its implications and treatment.