Whether or not antifibrinolytic therapy is employed, the patient should be followed closely for the level of IOP and the presence of corneal blood staining as the hyphema clears. Sustained elevation of IOP despite medical therapy is a definite indication for surgical intervention. Most commonly IOP is elevated due to outflow obstruction of the trabecular meshwork, primarily with red blood cells; however, in some cases pupillary block via a large clot may contribute to the elevated IOP. The levels and duration of IOP elevation necessitating surgery are somewhat arbitrary but good empirical guidelines have been suggested. Early studies involving manual clot extraction suggested better outcomes if surgery can be delayed for more than 4 days. Current microsurgical instruments and techniques may offer better results with earlier intervention if absolutely needed. An IOP of 25 mmHg or more for 5 days with a total hyphema or an IOP of 60 mmHg or more for 2 days are indications for surgery, the former to prevent corneal blood staining (Figures 6a, 6b) and the latter to prevent optic atrophy (Figure 7).
Corneal blood staining is a definite indication for surgical intervention in the amblyopic age group and a relative indication in older patients. The first recognizable signs of corneal blood staining are a straw-yellow discoloration of the deep stroma and tiny yellowish granules in the posterior stroma with blurring of its normal fibrillar appearance. Corneal blood staining develops when red blood cells release hemoglobin into the aqueous humor, which diffuses across the endothelium and Descemet’s membrane into the posterior corneal stroma. The hemoglobin is phagocytized by keratocytes and metabolized to hemosiderin. This becomes toxic to the keratocytes, resulting in their death, which releases more hemosiderin that diffuses more anteriorly in the corneal stroma. Eventually the epithelium may become involved and help to clear the cornea of hemosiderin and hemoglobin. Most blood staining clears from the periphery of the cornea toward the center and may take years. Usually complete clearing occurs (Figures 6c, 6d). Although there is death of keratocytes, there appears to be a repopulation with migration of peripheral fibrocytes resulting in little if any sustained corneal damage. With today’s microsurgical techniques, one could argue that any corneal blood staining is an indication for surgery; however, if the IOP is well managed medically, corneal blood staining will slowly clear with little sequelae.
Optic atrophy manifests as clinical pallor in the optic nerve head likely related to transient ischemia from extremely high IOP. Patients with sickle cell disease or trait occupy a special position in the surgical arena because mild and short-lived elevations in IOP can be extremely deleterious to the visual outcome of the patient by producing optic atrophy. Therefore, different guidelines have been identified as to the timing of surgery. In a patient with sickle cell disease or trait, an IOP above 25 mmHg for greater than 24 hours or repeated spiking of IOP beyond 30 mmHg daily for 2 to 4 days despite medical therapy would be a strong indication for surgical intervention. Any hyphema failing to resolve to less than 50% of the anterior chamber volume by 8 days is also an indication due to peripheral anterior synechiae formation. Patients with pre- existing glaucoma may also need earlier intervention.
Methods of Treatment
Multiple methods of surgical treatment have been suggested. General endotracheal anesthesia is recommended. Anterior chamber washouts, clot removal via vitrectomy instrumentation or irrigation/aspiration instrumentation, and trabeculectomies with associated iridectomies, have all been tried with differing degrees of success. Most surgeons will perform those procedures with which they are most comfortable and experienced. A paracentesis with a 30-gauge, 0.5-inch needle attached to a tuberculin syringe will provide short-term relief of extreme IOP spikes but is of little use with total hyphemas. If this is used during the first few days of hyphema management, care must be taken to avoid massive reduction in IOP, resulting in hypotony and possibly a rebleed.
Anterior Chamber Washout and Clot Removal
A simple two-port anterior chamber washout with nasal and temporal iris-plane clear corneal incisions has excellent success with limited manipulation of the intraocular structures. Balanced salt solution is irrigated through one corneal incision while the posterior portion of the other incision is depressed to evacuate blood. If an inadequate amount of blood is removed, a handheld irrigation/aspiration unit (eg, Simcoe) may be inserted into one corneal wound for gentle clot removal. Complete extraction is not necessary and attempts to do so may harm intraocular structures. Care should be taken to maintain a formed anterior chamber. Should intraoperative rebleeding occur, tamponade with a viscoelastic such as sodium hyaluronate 1% or air is helpful. Rarely, the site of bleeding may become visible and diathermy with a 23-gauge endodiathermy needle may be tried. The corneal wounds are closed with 10-0 nylon. Stromal hydration may also be a valid form of corneal wound closure depending on wound architecture and surgeon preference. Modern vitrectomy instrumentation is also used in clot evacuation. A single port with an irrigation/aspiration/cutting probe or a two-port method, with one irrigation probe and the other an aspiration/cutting probe, can be used to clear an anterior chamber clot using one or two clear corneal wounds as already mentioned. Care must be taken to avoid placing the cutting surface toward the human lens or iris for obvious reasons. Again, complete clot removal is unnecessary and unwise.
Trabeculectomy and Iridectomy
For large hyphemas or clots with profound elevation in IOP, a trabeculectomy and associated iridectomy are useful adjuncts to an anterior chamber washout. In this instance a washout, or partial clot removal by either previously mentioned technique, is typically performed through the trabeculectomy site. This would facilitate immediate IOP reduction, although the long-term success rates of these filtration surgeries would be limited. Care should be taken to secure the scleral flap to avoid early hypotony and to use releasable sutures or argon laser suture lysis for postoperative IOP control. There is no need for antimetabolites with these procedures unless the patient has pre-existing severe glaucoma. The iridectomy removes any component of pupillary block presumably from a collar button-like clot that often accompanies large hyphemas or 8-ball hyphemas. It can also be performed with the intraocular procedures mentioned.