A prospective study in 33 eyes (32 patients) with uncontrolled open angle glaucoma under clinical treatment. The trabecular tissue was scraped away from the angle (goniocurettage) in about 100 degrees by means of an instrument similar to a microchalazion curette. The goniocurettage was done under direct visualization of the angle through a gonioscopy lens (Swan-Jacob) and a surgical microscope. Using the 17.0 SPSS software the investigators compared the intraocular pressure, the numbers of antiglaucomatous medications, the best correct visual acuity, the development of cataract, the central corneal thickness,the impact on the visual field, the impact on the optic nerve head and the central corneal endothelial cell density before and after the goniocurettage, and the intra and post operative complications.