A Clinical Trial of Phacoemulsification Versus Phacoemulsification & the iStent Implantation in POAG Patients

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: NCT00847158
Recruitment Status : Completed
First Posted : February 19, 2009
Last Update Posted : February 19, 2009
Information provided by:
University of Turin, Italy

Brief Summary:
This was a prospective, double-masked, 15-month clinical trial comparing efficacy of phacoemulsification alone to combined phacoemulsification and implantation of the iStent® trabecular micro-bypass stent in patients with primary open-angle glaucoma.

Condition or disease Intervention/treatment Phase
Primary Open Angle Glaucoma and Cataracts Procedure: phacoemulsification alone Device: iStent Trabecular Micro-Bypass Stent Not Applicable

Detailed Description:

This was a prospective, randomized open-label study of 36 patients with POAG scheduled to undergo phacoemulsification with intraocular lens implantation ("cataract surgery"). Patients were randomized 2:1 to receive either cataract surgery alone (control group) or cataract surgery and iStent implantation (combined surgery group).

Implantation of the study stent occurred after cataract extraction and IOL insertion using the same small, temporal, clear-corneal incision (approximately 3 mm) used to perform phacoemulsification and IOL placement. The study stent was guided into Schlemm's canal using ab-interno gonioscopy (using a Swan-Jacobs gonioscope). (Figure 1) If no complications occurred during phacoemulsification, acetylcholine was injected in the anterior chamber after the IOL implantation to constrict the pupil. The anterior chamber was then filled with a viscoelastic agent to reform the anterior chamber and provide more clearance in the angle.

The anterior chamber was traversed with the applicator (the implant was on the tip of applicator) and the trabecular meshwork located. The leading edge of the device was gently slid through the trabecular meshwork and into Schlemm's canal at the nasal position (3 to 4 o'clock for the right eye; 9 to 8 o'clock for the left eye) with the tip of the implant directed inferiorly. If difficulty was encountered with the insertion at the primary location, we tried inserting about 0.5 clock hour inferiorly; and continued to move inferiorly as needed for subsequent attempts. Next, the device was released by pushing the button on the applicator, position of the stent was verified and the applicator was withdrawn.

The patients were instructed to discontinue all glaucoma medications after surgery. Standard post cataract extraction antibiotic and anti-inflammatory drug regimen was prescribed. Target pressure for each patient was determined prior to study entry. Following the assigned procedure, any patient with an IOP (as measured between 8 and 10 AM) that was greater than 2 mm Hg over their target was instructed to return twice in the following three days for re-measurement of their IOP. If the patient's IOP was > 2 mm Hg over their target pressure, ocular hypotensive agents were added. The medications were added in a pre-set schedule, with beta-blockers first, angiotensin-converting enzyme (ACE) inhibitors second, and prostaglandins third. If, however, on the third consecutive visit the patient's IOP was within 2 mm Hg of target, patient re-entered the normal visit schedule. Investigators were masked to treatment assignment both when measuring IOP and when determining when or if to add medications.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 36 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Treatment
Official Title: A Randomized, Double-Masked Clinical Trial of Phacoemulsification Compared With Phacoemulsification and Micro-Bypass Stent Implantation in Patients With POAG
Study Start Date : December 2006
Actual Primary Completion Date : March 2008
Actual Study Completion Date : March 2008

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Cataract Glaucoma
U.S. FDA Resources

Arm Intervention/treatment
Active Comparator: 1
phacoemulsification alone
Procedure: phacoemulsification alone
phacoemulsification alone
Other Names:
  • cataract surgery
  • Phaco
Active Comparator: 2
phacoemulsification and implantation of the iStent® trabecular micro-bypass stent
Device: iStent Trabecular Micro-Bypass Stent
phacoemulsification and implantation of the iStent® trabecular micro-bypass stent
Other Name: iStent, Trabecular micro-bypass stent, GTS100L, GTS100R

Primary Outcome Measures :
  1. Primary outcomes included IOP and reduction in medication use. [ Time Frame: 15 month ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • a previous diagnosis of POAG
  • an IOP of > 18 mm Hg at three separate visits if on one medication, or subjects on at least two medications with uncontrolled IOP on three separate visits.
  • all patients were deemed likely to follow surgeon instructions and were able to give informed consent.

Exclusion Criteria:

  • any glaucoma diagnosis other than POAG
  • the presence of peripheral anterior synechiae (PAS)
  • a cloudy cornea likely to inhibit gonioscopic view of the angle
  • any previous ocular surgery
  • history of trauma or ocular surface disease
  • the presence of peripheral anterior synechiae (PAS)
  • a cloudy cornea likely to inhibit gonioscopic view of the angle

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00847158

Sponsors and Collaborators
University of Turin, Italy
Principal Investigator: Antonio Fea, MD University of Torino

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Antonio Fea, University of Turin, Italy Identifier: NCT00847158     History of Changes
Other Study ID Numbers: iStent Washout study
First Posted: February 19, 2009    Key Record Dates
Last Update Posted: February 19, 2009
Last Verified: February 2009

Keywords provided by University of Turin, Italy:
Combination glaucoma & cataract procedure
trabecular micro-bypass stent

Additional relevant MeSH terms:
Glaucoma, Open-Angle
Ocular Hypertension
Eye Diseases
Lens Diseases