Prospective Randomized Comparison of One- versus Two-Site Phacotrabeculectomy: Two-Year Results
Presented at: University of Toronto Ophthalmology and Vision Sciences Departmental Research Day, June 2004, Toronto, Canada; Association for Research in Vision and Ophthalmology Meeting, May 2005, Fort Lauderdale, Florida; Third International Congress on Glaucoma Surgery, May 2006, Toronto, Canada; American Glaucoma Society 17th Annual Meeting, March 2007, San Francisco, California; Association for Research in Vision and Ophthalmology Meeting, May 2007, Fort Lauderdale, Florida; and Canadian Ophthalmology Society Meeting, June 2007, Montreal, Canada.
Received 15 June 2007; received in revised form 15 August 2007; accepted 12 September 2007. published online 03 January 2008.
Purpose
Previous studies have failed to find a significant difference in intraocular pressure (IOP) between one- and two-site phacotrabeculectomy. A possible explanation has been relatively small samples and short follow-up. We prospectively observed 80 patients for 2 years randomized to one- versus two-site phacotrabeculectomy with the primary outcome measure being IOP.
Design
Prospective randomized controlled study.
Participants
Eighty eyes were randomized and 79 underwent phacotrabeculectomy; 76 completed 24 months' follow-up.
Methods
Eligible patients scheduled for phacotrabeculectomy were randomized to one- or two-site phacotrabeculectomy after giving informed consent. A sample size of 54 was calculated to detect a difference of 2 mmHg between the groups with a power of 80%. Data recorded included demographics, visual acuity, IOP, endothelial cell counts, glaucoma medications, phacoemulsification settings, iris manipulation, suture lysis, needling, and complications. Follow-up data were obtained at 3, 6, 12, and 24 months.
Main Outcome Measure
Mean IOP at 24 months.
Results
There were no significant differences between the groups preoperatively. Mean IOPs were 17.6 versus 17.6, 12.6 versus 12.5, 13.1 versus 11.7, 13.1 versus 12.7, and 12.5 versus 12.9 mmHg for one- versus two-site at baseline and 3, 6, 12, and 24 months. There was a significant lowering of IOP compared with baseline at all time points (P<0.05). There was no significant difference in mean IOP between the groups at any time. The mean number of glaucoma medications decreased from 3.0 in each group to 0.2 and 0.4 for one- and two-site, respectively, at 24 months (P = 0.20). At 3 and 12 months, the endothelial counts (cells/mm2) were significantly lower in the two-site group: 2333 versus 2207 (P = 0.17), 2239 versus 1938 (P = 0.01), 2180 versus 1934 (P = 0.04), and 2147 versus 1947 (P = 0.08) at baseline and 3, 12, and 24 months, respectively. The surgical time was significantly longer for two-site (48.1±7.8 minutes) compared with one-site (39.2±6.4 minutes; P<0.001).
Conclusion
At 2 years after phacotrabeculectomy, there was no statistically significant difference in IOP between groups. Corneal endothelial cell counts were significantly lower in the two-site group at 3 and 12 months. Two-site surgery took significantly more time.
Available online: January 2, 2008.
1Department of Ophthalmology and Visual Sciences, Toronto Western Hospital, Toronto, Canada.
2Department of Public Health Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada.
Correspondence to Dr Yvonne M. Buys, Toronto Western Hospital, 399 Bathurst Street EW 6-405, Toronto, Ontario, Canada, M5T 2S8.
Manuscript no. 2007-804.
Supported by an unrestricted education grant from Pfizer Canada, Montreal, Canada.
ABSTRACT