What does the presence of bright red blood under the conjunctiva indicate?

The presence of bright red blood under the conjunctiva is indicative of a subconjunctival hemorrhage. This condition occurs when tiny blood vessels break just beneath the surface of the conjunctiva, resulting in a localized area of bleeding that appears bright red. Subconjunctival hemorrhages can occur due to a variety of factors including trauma, violent coughing or sneezing, or even spontaneously without any clear cause, and they are typically benign and self-limiting.

In contrast, conjunctival inflammation, characterized by redness as well, usually presents with additional symptoms such as discharge, itching, or irritation. Allergic reactions may involve redness but also include significant itching, tearing, and swelling. Corneal abrasions often lead to pain, sensitivity to light, and visual disturbances, rather than isolated redness beneath the conjunctiva. Each of these conditions presents with distinct clinical features that help differentiate them from subconjunctival hemorrhage.