A black eye (or "shiner") occurs when fluids collect in the tissues surrounding the eye after an injury near the eye.
Technically speaking, a black eye is a bruise or discoloration caused by broken blood vessels under the surface of the skin. Like other bruises, a black eye typically is accompanied by swelling.
Similar to bruises elsewhere on the body, a black eye usually is caused by blunt force trauma — a non-penetrating injury caused by impact. But there can be other causes as well.
What Is A Black Eye?
The clinical term for a black eye is periorbital hematoma. Though more difficult to pronounce, this medical term more accurately describes the condition — it is a collection of blood (hematoma) located in the tissues around, not inside, the eye (periorbital).
Any blunt force trauma to the eye socket or areas around it can damage small blood vessels under the skin and cause them to leak, leading to the development of a black eye or "shiner."
(The origin and meaning of the slang term "shiner" to describe a black eye is unknown. Some dictionaries say the term originated around 1904. It might have developed because the skin overlying a black eye sometimes can appear shiny. Another theory is that a black eye sometimes appears as though a person has applied a smudge of "black" used to shine shoes around his or her eye.)
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