Phacotrabeculectomy Meta-analysis

Abstract

It is a pleasure that both Gdih et al1Gdih G.A. Yuen D. Yan P. et al.Meta-analysis of 1- versus 2-site phacotrabeculectomy.Ophthalmology. 2011; 118: 71-76Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar and the authors independently performed 1- and 2-site phacotrabeculectomy specific meta-analyses. Gdih reported no statistically significant difference in intraocular pressure (IOP) reduction between 1- and 2-site phacotrabeculectomy at any time. However, we arrived at a somewhat different conclusion.Six studies were concurrently included in Gdih's and our meta-analyses. Two of Gdih's studies we excluded on doubt of sufficient randomization; another 2 our search failed to produce due to divergent search strategies. Gdih possibly excluded 2 of our studies based on the exclusion criteria of being retrospective studies;2Shingleton B.J. Price R.S. O'Donoghue M.W. Goyal S. Comparison of 1-site versus 2-site phacotrabeculectomy.J Cataract Refract Surg. 2006; 32: 799-802Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (11) Google Scholar a third one we only feature is very recent.4Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar Unlike Gdih's definition of IOP reduction, our study calculated the postoperative mean IOP. Postoperative IOP measurements ought to conform to the concept of a target IOP. Generally, a lower target IOP value (e.g., postoperative IOP in our study) implies better protection from vision field impairment in glaucoma patients. IOP reduction is regularly influenced by pre- and postoperative antiglaucoma medications. Therefore, we ought to treat surgery and medications as a whole, whereby the postoperative IOP measurement is a better indicator for evaluating clinical outcome.Our results showed that at 6 and 12 months postoperatively, the IOP was significantly lower in the 2-site group (P<0.05). We separately synthesized Gdih's 10 included studies, then all 13 studies to calculate the postoperative mean IOP for a meta-analysis (Table 1, available at http://aaojournal.org); the IOP was significantly lower in the 2-site group at 12 months and 6 and 12 months postoperatively (P<0.05), respectively.Table 1Pooled Estimates for Postoperative Intraocular Pressure for 1- Versus 2-Site Phacotrabeculectomy and Results of Three Different Meta-AnalysesFollow-up (m)No. of StudiesPooled Point Estimate for post- IOPWMD (fixed) 95% CIP for Overall Effect1-site2-siteMeta-analysis of our 9 included studies1Rossetti L. Bucci L. Miglior S. Orzalesi N. Temporal corneal phacoemulsification combined with separate-incision superior trabeculectomy vs standard phacotrabeculectomy: A comparative study.Acta Ophthalmol Scand Suppl. 1997; : 39PubMed Google Scholar, 2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 3Borggrefe J. Lieb W. Grehn F. A prospective randomized comparison of two techniques of combined cataract-glaucoma surgery.Graefes Arch Clin Exp Ophthalmol. 1999; 237: 887-892Crossref PubMed Scopus (46) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 11Shingleton B.J. Price R.S. O'Donoghue M.W. Goyal S. Comparison of 1-site versus 2-site phacotrabeculectomy.J Cataract Refract Surg. 2006; 32: 799-802Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar, 12Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (16) Google Scholar, 13Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar34(2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 13Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar)16.1015.34−0.86(-0.12, 1.84)0.0964(4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 13Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar)15.5414.47−1.07(-0.29, 1.85)0.007127(2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 11Shingleton B.J. Price R.S. O'Donoghue M.W. Goyal S. Comparison of 1-site versus 2-site phacotrabeculectomy.J Cataract Refract Surg. 2006; 32: 799-802Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar, 12Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (16) Google Scholar, 13Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar)15.6614.79−0.92(-0.47, 1.36)<0.001242(5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar)12.8512.04−0.97(-0.47, 2.41)0.19361(5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar)12.6011.70−0.90(-0.93, 2.73)0.34Meta-analysis of Gdih's 10 included studies1Rossetti L. Bucci L. Miglior S. Orzalesi N. Temporal corneal phacoemulsification combined with separate-incision superior trabeculectomy vs standard phacotrabeculectomy: A comparative study.Acta Ophthalmol Scand Suppl. 1997; : 39PubMed Google Scholar, 2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 3Borggrefe J. Lieb W. Grehn F. A prospective randomized comparison of two techniques of combined cataract-glaucoma surgery.Graefes Arch Clin Exp Ophthalmol. 1999; 237: 887-892Crossref PubMed Scopus (46) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 7Bellucci R. Luraschi M. Trabeculectomy and phacoemulsification: one-way and two-way approach compared after one year.Acta Ophthalmol Scand Suppl. 1998; : 50-51PubMed Google Scholar, 8Mandic Z. Ivekovic R. Petric I. Zoric-Geber M. Glaucoma triple procedure: a one-site vs. a two-site approach.Coll Antropol. 2000; 24: 367-371PubMed Google Scholar, 9Baradaran-Rafiee A. Yazdani S. Feizi S. Pakravan M. Single versus two-site phacoemulsification and mitomycin-C trabeculectomy.Iran J Ophthalmic Res. 2007; 2: 111-118Google Scholar, 10Bagli E. Gartzios C. Asproudis I. Kitsos G. Comparison of one-site versus two-site phacotrabeculectomy without the use of antimetabolites intraoperatively in patients with pseudoexfoliation glaucoma and primary open-angle glaucoma.Clin Ophthalmol. 2009; 3: 297-305Crossref PubMed Google Scholar34(2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 8Mandic Z. Ivekovic R. Petric I. Zoric-Geber M. Glaucoma triple procedure: a one-site vs. a two-site approach.Coll Antropol. 2000; 24: 367-371PubMed Google Scholar)15.1915.07−0.22(-0.71, 1.16)0.6464(4,5,6,8)14.9614.35−0.37(-0.45, 1.20)0.37126(2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 8Mandic Z. Ivekovic R. Petric I. Zoric-Geber M. Glaucoma triple procedure: a one-site vs. a two-site approach.Coll Antropol. 2000; 24: 367-371PubMed Google Scholar, 9Baradaran-Rafiee A. Yazdani S. Feizi S. Pakravan M. Single versus two-site phacoemulsification and mitomycin-C trabeculectomy.Iran J Ophthalmic Res. 2007; 2: 111-118Google Scholar)15.4114.45−1.01(-0.36, 1.66)0.002242(5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar)12.8512.04−0.97(-0.47, 2.41)0.19362(5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 10Bagli E. Gartzios C. Asproudis I. Kitsos G. Comparison of one-site versus two-site phacotrabeculectomy without the use of antimetabolites intraoperatively in patients with pseudoexfoliation glaucoma and primary open-angle glaucoma.Clin Ophthalmol. 2009; 3: 297-305Crossref PubMed Google Scholar)13.8513.44−0.05(-0.69, 0.59)0.88Meta-analysis of the total 13 included studies1Rossetti L. Bucci L. Miglior S. Orzalesi N. Temporal corneal phacoemulsification combined with separate-incision superior trabeculectomy vs standard phacotrabeculectomy: A comparative study.Acta Ophthalmol Scand Suppl. 1997; : 39PubMed Google Scholar, 2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 3Borggrefe J. Lieb W. Grehn F. A prospective randomized comparison of two techniques of combined cataract-glaucoma surgery.Graefes Arch Clin Exp Ophthalmol. 1999; 237: 887-892Crossref PubMed Scopus (46) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 7Bellucci R. Luraschi M. Trabeculectomy and phacoemulsification: one-way and two-way approach compared after one year.Acta Ophthalmol Scand Suppl. 1998; : 50-51PubMed Google Scholar, 8Mandic Z. Ivekovic R. Petric I. Zoric-Geber M. Glaucoma triple procedure: a one-site vs. a two-site approach.Coll Antropol. 2000; 24: 367-371PubMed Google Scholar, 9Baradaran-Rafiee A. Yazdani S. Feizi S. Pakravan M. Single versus two-site phacoemulsification and mitomycin-C trabeculectomy.Iran J Ophthalmic Res. 2007; 2: 111-118Google Scholar, 10Bagli E. Gartzios C. Asproudis I. Kitsos G. Comparison of one-site versus two-site phacotrabeculectomy without the use of antimetabolites intraoperatively in patients with pseudoexfoliation glaucoma and primary open-angle glaucoma.Clin Ophthalmol. 2009; 3: 297-305Crossref PubMed Google Scholar, 11Shingleton B.J. Price R.S. O'Donoghue M.W. Goyal S. Comparison of 1-site versus 2-site phacotrabeculectomy.J Cataract Refract Surg. 2006; 32: 799-802Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar, 12Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (16) Google Scholar, 13Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar35(2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 8Mandic Z. Ivekovic R. Petric I. Zoric-Geber M. Glaucoma triple procedure: a one-site vs. a two-site approach.Coll Antropol. 2000; 24: 367-371PubMed Google Scholar, 13Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar)16.3415.69−0.61(-0.16, 1.38)0.1265(4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 8Mandic Z. Ivekovic R. Petric I. Zoric-Geber M. Glaucoma triple procedure: a one-site vs. a two-site approach.Coll Antropol. 2000; 24: 367-371PubMed Google Scholar, 13Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar)15.8515.50−0.66(-0.00, 1.33)0.05129(2Wyse T. Meyer M. Ruderman J.M. et al.Combined trabeculectomy and phacoemulsification: a one-site vs a two-site approach.Am J Ophthalmol. 1998; 125: 334-339Abstract Full Text PDF PubMed Scopus (60) Google Scholar, 4el Sayyad F. Helal M. el-Maghraby A. et al.One-site versus 2-site phacotrabeculectomy: a randomized study.J Cataract Refract Surg. 1999; 25: 77-82Abstract Full Text PDF PubMed Scopus (50) Google Scholar, 5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 8Mandic Z. Ivekovic R. Petric I. Zoric-Geber M. Glaucoma triple procedure: a one-site vs. a two-site approach.Coll Antropol. 2000; 24: 367-371PubMed Google Scholar, 9Baradaran-Rafiee A. Yazdani S. Feizi S. Pakravan M. Single versus two-site phacoemulsification and mitomycin-C trabeculectomy.Iran J Ophthalmic Res. 2007; 2: 111-118Google Scholar, 11Shingleton B.J. Price R.S. O'Donoghue M.W. Goyal S. Comparison of 1-site versus 2-site phacotrabeculectomy.J Cataract Refract Surg. 2006; 32: 799-802Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar, 12Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (16) Google Scholar, 13Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar)15.8315.04−0.87(-0.46, 1.27)<0.001242(5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 6Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar)12.8512.04−0.97(-0.47, 2.41)0.19362(5Cotran P.R. Roh S. McGwin G. Randomized comparison of 1-site and 2-site phacotrabeculectomy with 3-year follow-up.Ophthalmology. 2008; 115: 447-454Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 10Bagli E. Gartzios C. Asproudis I. Kitsos G. Comparison of one-site versus two-site phacotrabeculectomy without the use of antimetabolites intraoperatively in patients with pseudoexfoliation glaucoma and primary open-angle glaucoma.Clin Ophthalmol. 2009; 3: 297-305Crossref PubMed Google Scholar)13.8513.44−0.05(-0.69, 0.59)0.88CI = confidence interval; IOP = intraocular pressure; m = month; post- = postoperative; WMD = weighted mean difference. Open table in a new tab These 3 different meta-analyses showed a significantly lower postoperative IOP in the 2-site phacotrabeculectomy subjects at mid-term but not long-term (24 and 36 months) follow-up (Table 1, available at http://aaojournal.org). Most studies reported IOP control at 12 months postoperatively, showing a lower mean IOP in the 2- than in the 1-site group. Gdih reported the IOP reduction to be numerically greater for the 2-site surgery (6.68 vs. 6.44 mmHg of the 1-site surgery). However, without statistically significant difference. Separate incisions for phacoemulsification and trabeculectomy are believed to reduce mechanical and thermal injury caused by the phacoemulsification tip, promoting minimal scarring. Decreased tissue manipulation at the trabeculectomy location in the 2-site procedure may contribute to mid-term IOP control. The observed IOP control difference (0.1 to 2.0 mmHg) at 6 and 12 months probably has no clinical significance. Nassiri reports no association of a lower mean IOP (0.6 to 1.4 mmHg) with better visual fields at 18-month follow-ups in 2-site compared with 1-site phacotrabeculectomy.4Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar Consequently, the level of IOP control of each group might suffice to stabilize visual field changes; overall the differences in IOP control between the 2 groups did not influence the clinical outcomes of glaucoma. The absence of visual field differences at 6 and 12 months in the current analysis confirms such an interpretation. For clarification, further studies of visual field changes are necessary.Long-term IOP control showed no significant difference between the 2 groups, but the analysis included only 4 studies with relatively small sample sizes. Multicenter or larger sample size randomized clinical trials (RCTs) will need to substantiate this conclusion. Due to increased scarring, the initial differences in the healing of the wounds of the 2 procedures possibly disappeared in the long term. The observed minimal difference ultimately had little effect on the overall functionality of the filtration incision.Coinciding with Gdih, our results showed no significant difference between the 2 groups regarding complications, except for a lower incidence of corneal endothelial cell (CEC) damage in the 1-site group.3Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (11) Google Scholar, 5Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar This likely reflects the more posterior location of the scleral tunnel incision in 1-site surgery, thus, less direct (phacoemulsification tip, intraocular lens insertion) and indirect (mechanical corneal striae) corneal endothelial damage. The study by Buys reported no significant difference in the preoperative mean CEC density, and a significantly lower CEC density in the 2-site group at 3 and 12 months postoperatively.5Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar Nassiri's multivariate analysis revealed an independently associated greater CEC loss in the 2-site procedure.3Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (11) Google ScholarIn conclusion, whether with minor or no statistically significant differences, 1- and 2-site phacotrabeculectomy show no clinical difference and both achieve similar IOP control. The 1-site approach is preferred for eyes with corneal endothelial disease or at high risk of endothelial damage,3Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (11) Google Scholar the 2-site surgery for patients at high risk of scleral conjunctival scarring.5Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar The choice of incision technique and site remains at the discretion of the surgeon. It is a pleasure that both Gdih et al1Gdih G.A. Yuen D. Yan P. et al.Meta-analysis of 1- versus 2-site phacotrabeculectomy.Ophthalmology. 2011; 118: 71-76Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar and the authors independently performed 1- and 2-site phacotrabeculectomy specific meta-analyses. Gdih reported no statistically significant difference in intraocular pressure (IOP) reduction between 1- and 2-site phacotrabeculectomy at any time. However, we arrived at a somewhat different conclusion. Six studies were concurrently included in Gdih's and our meta-analyses. Two of Gdih's studies we excluded on doubt of sufficient randomization; another 2 our search failed to produce due to divergent search strategies. Gdih possibly excluded 2 of our studies based on the exclusion criteria of being retrospective studies;2Shingleton B.J. Price R.S. O'Donoghue M.W. Goyal S. Comparison of 1-site versus 2-site phacotrabeculectomy.J Cataract Refract Surg. 2006; 32: 799-802Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 3Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (11) Google Scholar a third one we only feature is very recent.4Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar Unlike Gdih's definition of IOP reduction, our study calculated the postoperative mean IOP. Postoperative IOP measurements ought to conform to the concept of a target IOP. Generally, a lower target IOP value (e.g., postoperative IOP in our study) implies better protection from vision field impairment in glaucoma patients. IOP reduction is regularly influenced by pre- and postoperative antiglaucoma medications. Therefore, we ought to treat surgery and medications as a whole, whereby the postoperative IOP measurement is a better indicator for evaluating clinical outcome. Our results showed that at 6 and 12 months postoperatively, the IOP was significantly lower in the 2-site group (P<0.05). We separately synthesized Gdih's 10 included studies, then all 13 studies to calculate the postoperative mean IOP for a meta-analysis (Table 1, available at http://aaojournal.org); the IOP was significantly lower in the 2-site group at 12 months and 6 and 12 months postoperatively (P<0.05), respectively. CI = confidence interval; IOP = intraocular pressure; m = month; post- = postoperative; WMD = weighted mean difference. These 3 different meta-analyses showed a significantly lower postoperative IOP in the 2-site phacotrabeculectomy subjects at mid-term but not long-term (24 and 36 months) follow-up (Table 1, available at http://aaojournal.org). Most studies reported IOP control at 12 months postoperatively, showing a lower mean IOP in the 2- than in the 1-site group. Gdih reported the IOP reduction to be numerically greater for the 2-site surgery (6.68 vs. 6.44 mmHg of the 1-site surgery). However, without statistically significant difference. Separate incisions for phacoemulsification and trabeculectomy are believed to reduce mechanical and thermal injury caused by the phacoemulsification tip, promoting minimal scarring. Decreased tissue manipulation at the trabeculectomy location in the 2-site procedure may contribute to mid-term IOP control. The observed IOP control difference (0.1 to 2.0 mmHg) at 6 and 12 months probably has no clinical significance. Nassiri reports no association of a lower mean IOP (0.6 to 1.4 mmHg) with better visual fields at 18-month follow-ups in 2-site compared with 1-site phacotrabeculectomy.4Nassiri N. Nassiri N. Mohammadi B. Rahmani L. Comparison of 2 surgical techniques in phacotrabeculectomy: 1 site versus 2 sites.Eur J Ophthalmol. 2010; 20: 316-326PubMed Google Scholar Consequently, the level of IOP control of each group might suffice to stabilize visual field changes; overall the differences in IOP control between the 2 groups did not influence the clinical outcomes of glaucoma. The absence of visual field differences at 6 and 12 months in the current analysis confirms such an interpretation. For clarification, further studies of visual field changes are necessary. Long-term IOP control showed no significant difference between the 2 groups, but the analysis included only 4 studies with relatively small sample sizes. Multicenter or larger sample size randomized clinical trials (RCTs) will need to substantiate this conclusion. Due to increased scarring, the initial differences in the healing of the wounds of the 2 procedures possibly disappeared in the long term. The observed minimal difference ultimately had little effect on the overall functionality of the filtration incision. Coinciding with Gdih, our results showed no significant difference between the 2 groups regarding complications, except for a lower incidence of corneal endothelial cell (CEC) damage in the 1-site group.3Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (11) Google Scholar, 5Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar This likely reflects the more posterior location of the scleral tunnel incision in 1-site surgery, thus, less direct (phacoemulsification tip, intraocular lens insertion) and indirect (mechanical corneal striae) corneal endothelial damage. The study by Buys reported no significant difference in the preoperative mean CEC density, and a significantly lower CEC density in the 2-site group at 3 and 12 months postoperatively.5Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar Nassiri's multivariate analysis revealed an independently associated greater CEC loss in the 2-site procedure.3Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (11) Google Scholar In conclusion, whether with minor or no statistically significant differences, 1- and 2-site phacotrabeculectomy show no clinical difference and both achieve similar IOP control. The 1-site approach is preferred for eyes with corneal endothelial disease or at high risk of endothelial damage,3Nassiri N. Nassiri N. Rahnavardi M. Rahmani L. A comparison of corneal endothelial cell changes after 1-site and 2-site phacotrabeculectomy.Cornea. 2008; 27: 889-894Crossref PubMed Scopus (11) Google Scholar the 2-site surgery for patients at high risk of scleral conjunctival scarring.5Buys Y.M. Chipman M.L. Zack B. et al.Prospective randomized comparison of one- versus two-site phacotrabeculectomy two-year results.Ophthalmology. 2008; 115: 1130-1133Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar The choice of incision technique and site remains at the discretion of the surgeon. Meta-analysis of 1- versus 2-Site PhacotrabeculectomyOphthalmologyVol. 118Issue 1PreviewComparison of efficacy of intraocular pressure (IOP) reduction between 1- versus 2-site phacotrabeculectomy. Full-Text PDF