What can cause a subconjunctival hemorrhage?

A subconjunctival hemorrhage occurs when there is bleeding underneath the conjunctiva, which is the clear membrane that covers the white part of the eye. One of the most common causes of this condition is excessive eye rubbing. Rubbing the eyes can create enough pressure to break small blood vessels, resulting in blood leaking into the conjunctival space. This often appears as a bright red patch on the white of the eye, which may look alarming but typically does not cause pain or impact vision.

While viral infections, allergic reactions, and prolonged screen time can contribute to various eye symptoms or discomfort, they are not directly associated with causing bleeding beneath the conjunctiva in the same way that excessive eye rubbing is. Viral infections may lead to inflammation or redness, allergic reactions can cause itchy and watery eyes, and prolonged screen time might lead to eye strain or dryness, but none of these typically result in the specific condition of a subconjunctival hemorrhage. Hence, excessive eye rubbing is the most relevant cause among the options provided.