OBJECTIVE To study the complications of Neodymium:YAG (Nd:YAG) goniopuncture after deep sclerectomy with collagen implant (DSCI). METHODS All patients who underwent a Nd:YAG goniopuncture after a successful DSCI for primary open-angle glaucoma were included in a non-randomized clinical study. RESULTS Nd:YAG goniopuncture was performed in 31 patients. The mean time from surgery to goniopuncture was 3.2 +/- 3.2 months. The mean intraocular pressure (IOP) before goniopuncture was 32.0 +/- 10.8 mmHg (SD); the mean IOP 1-2 hours after goniopuncture was 16.5 +/- 6.3 mmHg. After a mean follow-up of 5.4 +/- 2.8 months, the mean IOP was 17.8 +/- 11.6 mmHg. Three patients had a spontaneous iris prolapse after Nd:YAG goniopuncture and consequently high IOP. No signs of severe hypotension were observed. CONCLUSIONS There are potentially serious complications relating to Nd:YAG goniopuncture after deep sclerectomy. However, further studies are needed to determine the safest time and level of IOP at which to perform Nd:YAG goniopuncture.