What is a common cause of hyphema?

Hyphema, which refers to the accumulation of blood in the anterior chamber of the eye, is most commonly caused by trauma. This trauma can be either blunt, such as a sports injury or an accident, or penetrating, like a stab wound or an injury from a sharp object. The impact can cause blood vessels in the eye to rupture, leading to bleeding in the anterior chamber.

In the context of other potential causes, allergic reactions typically do not result in bleeding in the eye; rather, they may cause redness, itching, and watery eyes. Diabetes mellitus can lead to a variety of eye problems, such as diabetic retinopathy, but it is not a direct cause of hyphema. Age-related changes in the eye may affect overall ocular health but are not directly responsible for bleeding into the anterior chamber like trauma is. Therefore, trauma is the clear and established cause associated with hyphema.