[Indications for the location of trabeculotomy in simple glaucoma. I. The blood contents of Schlemm's canal].

Following trabeculotomy, about 30% of glaucomatous eyes are not normalized in pressure without additional therapy. In these cases, it was not possible to remove the resistance of outflow completely. Before deciding to perform trabeculotomy it is, therefore, necessary to localize the resistance of outflow. The inspection of the blood pattern in Schlemm's canal gives no indication where to localize the resistance of outflow. The same holds true for the haemorrhage deriving from Schlemm's canal, in the operating field (trabeculotomy window), which appears in 19.2% of cases. After trabeculotomy the blood outflow into the anterior chamber is significantly higher (63.6%) using the suction cup, then following pressure of the gonioscopy lens (28.1%). The differences between these findings are discussed. Our results indicate the necessity to search for other methods in localizing the resistance of outflow pre-operatively.