March 2012
Volume 53, Issue 14
ARVO Annual Meeting Abstract  |   March 2012
Three Year Results of the Ahmed Baerveldt Comparison (ABC) Study
Author Affiliations & Notes
  • Donald L. Budenz
    Ophthalmology, University of North Carolina, Chapel Hill, North Carolina
  • Keith Barton
    Glaucoma Service, Moorfields Eye Hospital, London, United Kingdom
  • William J. Feuer
    Biostatistics, Univ of Miami-Bascom Palmer, Miami, Florida
  • Joyce C. Schiffman
    Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida
  • Vital P. Costa
    Ophthalmology, University of Campinas, Sao Paulo, Brazil
  • David Godfrey
    Glaucoma Associates of Texas, Dallas, Texas
  • Yvonne M. Buys
    Ophthalmology & Vision Sciences, University of Toronto, Toronto, Ontario, Canada
  • Ahmed Baerveldt Comparison Study Group
    Ophthalmology, University of North Carolina, Chapel Hill, North Carolina
  • Footnotes
    Commercial Relationships  Donald L. Budenz, None; Keith Barton, Abbott Medical Optics (R), New World Medical (R); William J. Feuer, None; Joyce C. Schiffman, None; Vital P. Costa, None; David Godfrey, None; Yvonne M. Buys, None
  • Footnotes
    Support  NIH Grant P30 EY014801; Research to Prevent Blindness; New World Medical
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 6355. doi:
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      Donald L. Budenz, Keith Barton, William J. Feuer, Joyce C. Schiffman, Vital P. Costa, David Godfrey, Yvonne M. Buys, Ahmed Baerveldt Comparison Study Group; Three Year Results of the Ahmed Baerveldt Comparison (ABC) Study. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6355.

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      © ARVO (1962-2015); The Authors (2016-present)

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To compare the safety and efficacy of the Ahmed Glaucoma Valve (model FP7) to the Baerveldt Glaucoma Implant (model 101-350) in patients with refractory glaucoma after three years of follow-up.


Patients 18 to 85 years of age with refractory glaucoma having intraocular pressure (IOP) of 18 mmHg or more in whom an aqueous shunt was planned were randomized to undergo implantation of either an Ahmed or a Baerveldt implant. The main outcome measures were IOP, visual acuity, use of supplemental medical therapy, complications, and failure (IOP > 21 mm Hg or not reduced by 20%, IOP ≤ 5 mm Hg, reoperation for glaucoma or removal of implant, or loss of light perception vision).


Retention rates at 18, 24, and 36 months respectively were 92%, 87%, and 75%. The risk of failure by any criterion was similar for the Ahmed and Baerveldt implants (risk ratio = 1.0, p=0.88, 95% CI=0.7, 1.6); however, the risk of reoperation for glaucoma was 2.0 times higher with the Ahmed implant than the Baerveldt implant (p=0.074, 95% CI=0.9, 4.4). At 36 months, mean (SD) IOP was 14.3 mmHg (4.9) in the Ahmed group and 12.9 mmHg (4.4) in the Baerveldt group (p=0.049). The mean (SD) number of IOP lowering medicines was 1.9 (1.4) in the Ahmed group and 1.5 (1.4) in the Baerveldt group (p=0.048).


There was no difference in failure rates, but the modestly better intraocular pressure control with the Baerveldt implant compared to the Ahmed implant seen at one year follow-up persisted through 3 years.  

Clinical Trial: NCT00376363

Keywords: clinical (human) or epidemiologic studies: outcomes/complications 

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