title: Comparing polymethylmethacrylate implant with collagen implant in deep sclerectomy: a randomized controlled trial.
abstract: OBJECTIVE
  To compare the intraocular pressure (IOP) lowering effect and safety of a new rigid, nonabsorbable polymethylmethacrylate implant (PMMA) with the commercially available cylindrical collagen implant used in deep sclerectomy procedure.
  
  
  METHODS
  Nonpenetrating deep sclerectomy was performed on all patients. Patients were randomly assigned to receive either a PMMA implant or a collagen implant.
  
  
  METHODS
  The trial involved 60 patients (60 eyes) with medically uncontrolled primary and secondary open-angle glaucoma who were randomized to receive either a PMMA implant (30 eyes) or the collagen implant (30 eyes). The patients were examined before and after the operation 1 day before surgery and at day 1; weeks 1, 2 and 3; and months 1, 2, 3, 6, 9, 12, 18, 24, and 30. At each visit, the following examinations were performed: slit lamp examination, tonometry, visual acuity, and fundoscopy.
  
  
  RESULTS
  The mean follow-up period was 20.4 (SD 12.4) months (PMMA) and 15.1 (SD 7.7) months (collagen) (P=NS). The mean preoperative IOP was 21.4 (SD 7.1) mm Hg (PMMA) and 21.0 mm Hg (SD 5.4) (collagen). The mean postoperative IOP was 7.4 (SD 4.5) mm Hg (PMMA) and 5.4 (SD 4.4) mm Hg (collagen) at day 1 (P=NS), 15.7 (SD 5.0) mm Hg (PMMA) and 14.7 (SD 5.0) mm Hg (collagen) at month 1 (P=NS), and 13.8 (SD 4.8) mm Hg (PMMA) and 13.3 (SD 2.4) mm Hg (collagen) at month 12 (P=NS). Seven patients had perforations of the trabeculo-Descemet membrane and were excluded from the analysis. At the last follow-up visit, 42% of PMMA patients and 44% of collagen patients achieved an IOP of 21 mm Hg or less without medication (P=NS). The number of medications was reduced from 2.4 (SD 1.0) to 0.6 (SD 0.6) (P<0.001) in the PMMA group, and from 2.4 (SD 1.1) to 0.7 (SD 0.8) (P<0.001) in the collagen group. There were no significant differences between the 2 groups in postoperative and transient complications.
  
  
  CONCLUSIONS
  The new PMMA implant offered success and complication rates equal to those of the collagen implant. The new PMMA implant could serve as a low-cost alternative to the collagen implant and render the use of deep sclerectomy with an implant affordable for settings with limited financial resources.
authors.affiliation: Hôpital Ophtalmique Jules Gonin, Department of Ophthalmology, University of Lausanne, Switzerland.
authors.forename: Kaweh
authors.initials: K
authors.lastname: Mansouri
authors.forename: Tarek
authors.initials: T
authors.lastname: Shaarawy
authors.forename: Andreas
authors.initials: A
authors.lastname: Wedrich
authors.forename: André
authors.initials: A
authors.lastname: Mermoud
mesh_terms: D000368:Aged; D000477:Alkylating Agents / Q000008:administration & dosage; D003094:Collagen; D003131:Combined Modality Therapy; D005260:Female; D005901:Glaucoma / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000008:administration & dosage; D019904:Polymethyl Methacrylate; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012599:Sclerostomy / Q000379:methods*; D014065:Tonometry, Ocular; D014792:Visual Acuity
chemical_list: D000477:Alkylating Agents; D016685:Mitomycin; D003094:Collagen; D019904:Polymethyl Methacrylate