Bleeding can occur in any part of the eye, from the superficial external outer layer, the conjunctiva, to the lining of the back of the eye, the retina. Eye hemorrhages may cause no symptoms at all or cause total vision loss and severe pain, depending on the location. Many disease processes and injuries can lead to hemorrhages in the eye.
Although they look frightening, hemorrhages under the conjunctiva, the tissue that covers the sclera, the white part of the eye, are usually harmless. A subconjunctival hemorrhage may be just a small red dot over the white of the eye or may cover most of the white of the eye. Causes include trauma to the eye, such as an injection, coughing, sneezing, laughing, straining to have a bowel movement or lifting something heavy. Taking blood-thinning medication such as aspirin, heparin or warfarin may also cause subconjunctival hemorrhage. It may take a week to 10 days for the redness to subside, but no treatment proves necessary unless the eye becomes painful, vision decreases or light sensitivity develops.
Hyphema, blood between the cornea, the dome shaped covering of the eye and the iris, the colored part of the eye, can occur from trauma or disease processes. Hyphema most often results from blunt or penetrating trauma. Medications that increase bleeding tendencies and diseases that result in abnormal blood vessel formation in the iris of the eye, like tumors or diabetes can all cause hyphema. The white of the eye may contain blood, which may pool at the bottom of the cornea when a person is upright. Pain and a change in the shape or appearance of the pupil may also occur. Vision becomes affected because the amount of light that enters the eye decreases and becomes more affected when more blood is present.
Vitreous hemorrhage, bleeding into the vitreous jelly that forms the center part of the eye, can occur after trauma or from leakage from abnormal retinal vessels. Vitreous hemorrhage can't be seen by looking at the eye; a slit lamp examination through the dilated pupil is needed to see a vitreous hemorrhage. Symptoms include sudden loss of vision, flashes of light and floaters, small particles that pass in and out of the line of vision.
Retinal hemorrhages aren't visible from the outside of the eye, but can be seen through a dilated pupil slit lamp exam. Retinal hemorrhages result from wet macular degeneration, diabetic retinopathy, high blood pressure, trauma or blockages in the blood vessels of the eye. Vision loss remains the most common symptom of retinal hemorrhage. Treatment depends on the cause but may include intravitreal injection of medications to block formation of abnormal blood vessels or laser.