What is the condition caused by an infection of an oil gland of the eyelid leading to an abscess?

The condition caused by an infection of an oil gland in the eyelid leading to an abscess is a hordeolum, commonly known as a stye. A hordeolum typically presents as a painful, swollen lump on the eyelid and is often due to the blockage of an oil gland, leading to bacterial infection and inflammation. This condition is characterized by localized redness and tenderness, which can significantly affect a person's comfort and vision if left untreated.

In contrast, iritis refers to inflammation of the iris and typically does not involve the oil glands of the eyelid. A cataract is a clouding of the eye's lens, leading to diminished vision, and myopia is a refractive error characterized by difficulty seeing distant objects clearly. Neither of these conditions relates to the infection of the oil glands. Therefore, understanding the specific nature of a hordeolum and its symptoms helps clarify why this is the correct answer.