The AVB Study: Prospective Study Comparing the Ahmed Valve and the Baerveldt Implant for Treating Refractory Glaucoma

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00940823
Recruitment Status : Completed
First Posted : July 16, 2009
Results First Posted : March 13, 2018
Last Update Posted : March 13, 2018
Glaucoma Research Society of Canada
Information provided by (Responsible Party):
Panos G. Christakis, Credit Valley EyeCare

Study Type: Interventional
Study Design: Allocation: Randomized;   Intervention Model: Parallel Assignment;   Masking: None (Open Label);   Primary Purpose: Treatment
Condition: Glaucoma
Interventions: Device: Ahmed FP7 Valve
Device: Baerveldt-350 Tube

  Participant Flow

Recruitment Details
Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
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Pre-Assignment Details
Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
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Reporting Groups
Ahmed Group Ahmed FP7 Valve Implant
Baerveldt Group Baerveldt-350 Implant

Participant Flow:   Overall Study
    Ahmed Group   Baerveldt Group
STARTED   124   114 
COMPLETED   89   82 
NOT COMPLETED   35   32 
Death                8                12 
Lost to Follow-up                27                20 

  Baseline Characteristics

Population Description
Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
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Reporting Groups
Ahmed Group Patients received an Ahmed-FP7 valve implant at the time of surgery.
Baerveldt Group Patients received a Baerveldt-350 implant at the time of surgery.
Total Total of all reporting groups

Baseline Measures
   Ahmed Group   Baerveldt Group   Total 
Overall Participants Analyzed 
[Units: Participants]
 124   114   238 
[Units: Years]
Mean (Standard Deviation)
 65  (17)   67  (15)   66  (16) 
Sex: Female, Male 
[Units: Participants]
Count of Participants
Female      59  47.6%      73  64.0%      132  55.5% 
Male      65  52.4%      41  36.0%      106  44.5% 
Race (NIH/OMB) 
[Units: Participants]
Count of Participants
American Indian or Alaska Native      0   0.0%      0   0.0%      0   0.0% 
Asian      13  10.5%      15  13.2%      28  11.8% 
Native Hawaiian or Other Pacific Islander      0   0.0%      0   0.0%      0   0.0% 
Black or African American      15  12.1%      13  11.4%      28  11.8% 
White      96  77.4%      86  75.4%      182  76.5% 
More than one race      0   0.0%      0   0.0%      0   0.0% 
Unknown or Not Reported      0   0.0%      0   0.0%      0   0.0% 
Intraocular Pressure 
[Units: mmHg]
Mean (Standard Deviation)
 31.1  (10.5)   31.7  (11.1)   31.4  (10.8) 
Glaucoma Medication Use 
[Units: Medications]
Mean (Standard Deviation)
 3.1  (1.0)   3.1  (1.1)   3.1  (1.0) 
Prior Laser Therapies 
[Units: Laser procedures]
Mean (Standard Deviation)
 0.8  (1.1)   1.0  (1.1)   0.9  (1.1) 
Prior Ocular Surgeries 
[Units: Ocular Surgeries]
Mean (Standard Deviation)
 1.8  (1.3)   1.6  (1.1)   1.7  (1.2) 
Mean logMAR (converted) Visual Acuity [1] 
[Units: Units on a scale]
Mean (Standard Deviation)
 1.3  (1.0)   1.3  (1.1)   1.3  (1.1) 

LogMAR Visual Acuity is calculated by taking the log(Snellen Acuity/20). Normal vision (20/20) corresponds to 0 and complete blindness (no light perception, designated as 20/64000) corresponds to 3.5.

Hence, the lower the logMAR value, the better the vision.

  Outcome Measures

1.  Primary:   Number of Participants With Surgical Failure (Composite Measure)   [ Time Frame: 5 years ]

2.  Secondary:   Intraocular Pressure (IOP)   [ Time Frame: 5 years ]

3.  Secondary:   Anti-glaucoma Medications   [ Time Frame: 5 years ]

4.  Secondary:   LogMAR Snellen Visual Acuity   [ Time Frame: 5 years ]

5.  Secondary:   Number of Participants With Complications During or After Surgery   [ Time Frame: 5 years ]

6.  Secondary:   Number of Participants With Interventions After Surgery   [ Time Frame: 5 years ]

  Serious Adverse Events

  Other Adverse Events

  Limitations and Caveats

Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
  1. Using predetermined IOP cutoffs may not reflect individual patient outcomes.
  2. Visual field progression was not an outcome criteria due to the poor baseline vision of patients.
  3. Results can only be applied to patients with advanced glaucoma.

  More Information

Certain Agreements:  
Principal Investigators are NOT employed by the organization sponsoring the study.
There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.

Results Point of Contact:  
Name/Title: Dr. Iqbal Ike K. Ahmed
Organization: Prism Eye Institute
phone: 905-456-3937

Publications of Results:
Other Publications:

Responsible Party: Panos G. Christakis, Credit Valley EyeCare Identifier: NCT00940823     History of Changes
Other Study ID Numbers: CVEC-AVB
GRSC-2005 ( Other Identifier: Glaucoma Research Society of Canada )
First Submitted: July 15, 2009
First Posted: July 16, 2009
Results First Submitted: August 21, 2016
Results First Posted: March 13, 2018
Last Update Posted: March 13, 2018