Hyphema is a condition in which the anterior chamber of the eye becomes filled with blood. The anterior chamber is located between the iris and the cornea, and is filled with a liquid called aqueous humor. When hyphema occurs and the chamber contains blood, the effect is often to partially or fully obscure the pupil of the eye, making this condition relatively easy to notice and diagnose.
While hyphema itself is readily apparent, what is not always apparent is the means by which the condition occurred. The most common cause is a traumatic injury to the eye, but certain medical conditions can also lead to the presence of blood in the anterior chamber. Conditions such as diabetes, cancers such as retinoblastoma, and structural vascular abnormalities in or near the eye, may contribute to the development of a spontaneous hyphema. Blood may also fill the anterior chamber of the eye during or after eye surgery.
Regardless of the event that precipitates the injury, the underlying cause of most hyphemas is the same type of event. In most cases, tissue in the posterior region of the eye is displaced due to an impact injury, and this causes a sudden shift that displaces and may tear both the iris and the lens of the eye. If a tear occurs, the anterior chamber can begin to accumulate blood.
Hyphemas are usually classified according to the amount of blood filling the anterior chamber, and the condition of the blood. Grade 1 injuries are those in which blood fills less than one third of the chamber. In Grade 2 injuries, the chamber is one third to one half filled with blood. A Grade 3 injury means the anterior chamber is at least half filled, and may be completely filled with blood. In a Grade 4 injury the blood in the anterior chamber has clotted.
The majority of these injuries are of the Grade 1 variety, with nearly 60% involving an anterior chamber no more than one third full. In around 15% of cases, the chamber is between one half and completely filled. While only Grade 4 refers to clotted blood specifically, it should be noted that overall, approximately 40% of hyphemas involve at least a small clot.
Hyphema treatment typically consists of bed rest, an eye patch, and medication to prevent further bleeding, limit inflammation, and promote healing. When hyphemas occurs without complications, they normally clear up within one week and result in recovery of at least 20/40 vision in the injured eye. In some cases, however, particularly when large clots form, the injury may lead to more severe vision loss.
