Blood reflux into anterior chamber after trabeculectomy

A total of 90 eyes of 73 patients with various types of glaucoma underwent trabeculectomy and were under follow-up for a period ranging from 6 months to 8 years, with a mean of 32 months. Gonioscopy was performed using a Goldmann two-mirror contact lens; when at least one end of the internal trabeculectomy opening at the level of the trabecular tissue was free from iris adhesion the condition was designated as M1, and as M0 when the iris adhered to both ends of the opening. When the bottom of the trabeculectomy opening was visible, the condition was designated as H1, otherwise as H0. The condition of the trabeculectomy opening was then classified into three types, M1H1, M0H1 and M0H0; there were 40, 29 and 13 eyes, respectively, in each type, and in 8 eyes the condition was unclassifiable. On compression of the sclera with the base of the contact lens, a blood reflux into the anterior chamber from the vicinity of the cut ends of the Schlemm's canal was seen to occur in 22 out of 40 eyes with M1H1; this phenomenon was not observed in the other types. The incidence of the blood reflux was not correlated with the postoperative period, but intraocular pressure (IOP) control was significantly more successful in eyes with the blood reflux than those without this phenomenon. The IOP control was better in eyes with visible filtering bleb than in those without the bleb, and in eyes without the bleb, the IOP control was far superior in eyes with the blood reflux than in those without it. Tonography in selected eyes showed that the outflow facility was significantly higher in eyes with the blood reflux than in those without it. It was thought that aqueous filtration into the veins near the cut ends of the Schlemm's canal played a significant role in the IOP control after trabeculectomy.