Describe traumatic hyphaema with its complications and management.

Nature, Grading and Complications

• Grading by the proportion of the anterior chamber filled — microhyphaema, circulating red cells visible only at the slit lamp; grade I, less than one-third; grade II, one-third to one-half; grade III, more than half but not total; and grade IV, a total hyphaema. A total hyphaema of bright red blood is called an "eight-ball" or black-ball hyphaema when it clots and becomes dark.
• The two dangers are raised pressure and RE-bleeding, and management is directed at both

Management

• Conservative treatment succeeds in the great majority:
• Rest with the head elevated to 30 to 45 degrees, which lets the blood settle inferiorly, clearing the visual axis and keeping the clot away from the trabecular meshwork and the corneal endothelium
• A rigid shield to prevent further injury; and avoidance of strenuous activity, straining and bending
• Topical steroid to reduce inflammation and, it is believed, the risk of re-bleeding; and a cycloplegic (atropine), which relieves pain, prevents synechiae and, by keeping the pupil still, reduces movement of the iris vessels
• Stop aspirin and other antiplatelet and anticoagulant drugs where clinically permissible, and avoid non-steroidal analgesics; paracetamol is the analgesic of choice
• Control the pressure with topical beta-blockers and alpha-2 agonists; and acetazolamide except in sickling disorders
• Antifibrinolytics — oral tranexamic acid or aminocaproic acid — reduce re-bleeding by stabilising the clot; their use varies, and they cause nausea and postural hypotension
• Daily review for the first 5 days, with acuity, pressure and the height of the hyphaema recorded, since re-bleeding occurs in this window
• Indications for surgical evacuation — and the aim is to prevent optic atrophy and corneal staining: uncontrolled raised pressure (above 50 mmHg for 5 days, or above 35 for 7 days, in a normal patient; far lower thresholds in sickling disease); early corneal blood staining, which is an urgent indication; a total hyphaema persisting beyond 5 days; and a large clot failing to resolve.
• Techniques — anterior chamber washout through a paracentesis; clot expression; and automated aspiration or vitrectomy-assisted removal; with a trabeculectomy where the pressure is uncontrolled
• Do not evacuate too early; disturbing a fresh clot at 2 to 4 days may precipitate bleeding, and the optimum is after day 4