The so-called black eye is caused by bleeding beneath the skin around the eye. Sometimes a black eye indicates a more extensive injury, even a skull fracture, particularly if the area around both eyes is bruised (raccoon eyes) or if there has been a head injury.
Although most black eye injuries aren't serious, sometimes there is an accompanying injury to the eyeball itself sufficient to cause bleeding inside the eye. Bleeding in the front part of the eye, called hyphema, is serious and can reduce vision and damage the cornea — the clear, protective "window" at the front of the eye. In some cases, abnormally high pressure inside the eyeball (glaucoma) also can result. For this reason, it's advisable to have an eye specialist examine your eyeball if there has been enough of an injury to cause a black eye.
To take care of a black eye:
Using gentle pressure, apply a cold pack or a cloth filled with ice to the area around the eye. Take care not to press on the eye itself. Apply cold as soon as possible after the injury to reduce swelling, and continue using ice or cold packs for 24 to 48 hours.
Look for evidence of blood within the white and colored parts of the eye. If blood can be seen in either of these sites, seek urgent care by an eye specialist (ophthalmologist).
Seek medical care immediately if you experience vision problems (double vision, blurring), severe pain, or bleeding in the eye or from the nose.