PURPOSE: To study the need, the safety and the success rate of collagen implant in eyes that underwent deep sclerectomy, a new non penetrating filtration procedure, we compared the results of deep sclerectomy with (DSCI) and without (DS) collagen implant. METHODS: Of 168 patients (168 eyes) with various types of medically uncontrolled open angle glaucoma, 86 (86 eyes) underwent DSCI, and 82 (82 eyes) underwent DS. Visual acuity, slit lamp examination, intraocular pressure (IOP) measurements were performed before surgery and prospectively at days 1 and 7 and months, 1, 2, 3, 6, 9, 12, 15, 18, and 24 after surgery. Deep sclerectomy was performed according to Kozlov's original technique. The collagen implant drainage device was radially secured in the center of the deep sclerectomy dissection. RESULTS: The mean follow-up period was 9.7 +/- 6.5 months for DSCI, and 9.0 +/- 4.8 months for DS. The mean preoperative IOP was 26.9 +/- 8.8 mmHg for DSCI and 25.8 +/- 8.5 mmHg for DS. The mean postoperative IOP and visual acuity were similar between the two groups. Complete and qualified success rates were better when the collagen implant was used (Log-Rank test: p = 0.0002 and 0.033 for complete and qualified success respectively). The need for postoperative glaucoma medications was significantly lower when the collagen implant was used (0.2 +/- 0.5 versus 0.5 +/- 0.7 medication per patient in the DSCI and DS respectively, Student's t test: p = 0.0038). There was significantly less bleb fibrosis when the collagen implant was used (2% and 11% in DSCI and DS respectively, p = 0.029). CONCLUSION: The collagen implant device is safe, increases the success rate of deep sclerectomy, and lowers the need for postoperative glaucoma medications.