During the period mentioned 150 laser iridectomies were performed using the pulsed argon laser (BRITT Corp). With the help of a specially developed three mirror glass, (Stiegler) it is possible, without exception, to penetrate the iris in one session, regardless of its color or the depth of the anterior chamber. The technique used, and the tonographic and histologic investigations and results are discussed. The findings provide a new insight into the mechanism of out flow in glaucoma.