Intraoperative Hyphema

Abstract

Hemorrhage is a common complication in trabeculectomy. Hyphema can be a manifestation of an intraoperative hemorrhage and has numerous potential causes. Although generally self-limited, severe complications are possible due to intraoperative hyphemas, and effort should be made to prevent or minimize their occurrence. Large clinical trials suggest that intraoperative hyphema is a common complication of filtration surgery. In the Advanced Glaucoma Intervention Study (AGIS), the investigators found a 13% prevalence of intraoperative anterior chamber bleeding in eyes treated with trabeculectomy (67 of 513 eyes). Similarly, the Collaborative Initial Glaucoma Treatment Study (CIGTS) found a hyphema prevalence of 8% in eyes (37 of 465 eyes) treated surgically. More recently, the Tube Versus Trabeculectomy Study reported an intraoperative hyphema rate of 3% (3 of 105 eyes) in the trabeculectomy arm of the trial. Ocular risk factors for an intraoperative hyphema include elevated intraocular pressure (IOP), a sudden drop in IOP as a result of filtration surgery, and surgical trauma, particularly an iridectomy. Additionally, the fragile rubeotic iris vessels that may be present in neovascular and inflammatory glaucomas may make those eyes especially susceptible to intraoperative (or postoperative) hyphema. Moreover, patients undergoing glaucoma surgery are often older and have multiple risk factors for intraoperative hemorrhage, including systemic hypertension and vasculopathy, as well as chronic oral anticoagulation therapy (ACT) or antiplatelet therapy (APT). Anterior chamber bleeding leading to a hyphema can occur at multiple stages of filtration surgery. Intraoperative bleeding tends to happen most commonly when cutting the iridectomy, due to direct incision of the major arterial circle of the iris or from damage to the adjacent highly vascular ciliary processes. Hemorrhage also may occur while excising the sclerostomy or following the creation of the paracentesis (especially if there is a large drop in IOP with consequent rupture of fragile rubeotic vessels). During dissection of the partial thickness scleral flap, aqueous or episcleral veins may be cut. If hemorrhage from these vessels is not adequately cauterized, blood may eventually flow into the anterior chamber.