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Completed

NCT Number: NCT00666237

Primary Tube Versus Trabeculectomy Study

The purpose of the Primary Tube Versus Trabeculectomy (PTVT) Study is to compare the long-term safety and efficacy of nonvalved tube shunt surgery to trabeculectomy with mitomycin C in eyes that have not had previous ocular surgery.

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Key information

Conditions

Glaucoma Eye Diseases Ocular Hypertension

Age range

18 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

University of Toronto, Toronto, Canada

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18-85 years
  • Glaucoma that is inadequately controlled on tolerated medical therapy with Intraocular Pressure (IOP) greater than or equal to 18 mm Hg and less than or equal to 40 mm Hg
  • No previous incisional ocular surgery

Exclusion criteria

  • Unwilling or unable to give consent, unwilling to accept randomization, or unable to return for scheduled protocol visits
  • Pregnant or nursing women
  • No light perception vision
  • Active iris neovascularization or active proliferative retinopathy
  • Iridocorneal endothelial syndrome
  • Epithelial or fibrous ingrowth
  • Chronic or recurrent uveitis
  • Steroid-induced glaucoma
  • Severe posterior blepharitis
  • Unwilling to discontinue contact lens use after surgery
  • Previous cyclodestructive procedure
  • Conjunctival scarring from prior ocular trauma or cicatrizing disease precluding a superior trabeculectomy
  • Functionally significant cataract
  • Need for glaucoma surgery combined with other ocular procedures or anticipated need for additional ocular surgery

Treatment and study plan

Tube shunt surgery

Procedure

The procedure involves implantation of a Baerveldt consisting of a tube that is connected to an end plate. The tube is inserted into the anterior chamber and shunts aqueous humor to the end plate located in the equatorial region of the eye. The aqueous humor is then absorbed by the tissues around the eye.

Other names: Baerveldt glaucoma implant

trabeculectomy

Procedure

The procedure involves removal of a small portion of trabecular meshwork and adjacent tissue under a partial thickness scleral flap. Aqueous humor drains into the subconjunctival space producing a filtering bleb. The aqueous humor then diffuse out of the bleb.

mitomycin C

Drug

A fluid retaining sponge soaked in 0.4 mg/ml Mitomycin C will be applied in the region of Trabeculectomy site for about 2 minutes

Primary outcomes

  1. Number of Participants With Surgical Failure

    Time frame: Up to 5 years

    Surgical failure is defined as:

    • Inadequate Intraocular Pressure (IOP) Reduction (IOP > 21 mmHg or reduced < 20% below baseline on 2 consecutive follow-up visits after 3 months)
    • Reoperation for glaucoma
    • Persistent hypotony (IOP ≤ 5 mmHg on 2 consecutive visits after 3 months)
    • Loss of light perception vision

Secondary outcomes

  1. Intraocular Pressure

    Time frame: At baseline, At 1 year, At 18 months, At 2 years, At 3 years, At 4 years, At 5 years

    Intraocular pressure will be reported in mmHg and measured using Goldmann applanation tonometry or a Tono-Pen.

  2. Number of Participants With Reported Postoperative Complications

    Time frame: Up to 5 years

    Number of participants with early and late postoperative complications will be reported as per treating physician assessment

  3. Visual Acuity Using a Snellen Chart

    Time frame: At Baseline, At 5 years

    Visual acuity will be measured using a Snellen chart on logMAR (Logarithm of Minimal Angle of Resolution) scale. Letter-by letter results calculated the visual performance score for each chart read. logMAR scores closer to zero, or below zero, indicate a better visual acuity. A logMAR visual performance score of 0.0 is equivalent to Snellen visual acuity of 20/20.

  4. Visual Acuity as Measured Using EDTRS Chart

    Time frame: At baseline, At 5 years

    Visual acuity will be reported as the number of correctly identified letters on the Early Treatment Diabetic Retinopathy Study (EDTRS) chart. Total score ranges from 0-100 with the higher score indicating better visual acuity.

  5. Visual Field

    Time frame: Up to 5 years

    Visual fields will be measured using standard automated perimetry.

  6. Reoperation for Glaucoma

    Time frame: Up to 5 years

    The number of participants requiring reoperation for glaucoma will be reported

  7. Number of Glaucoma Medications

    Time frame: At Baseline, At 1 year, At 18 months, At 2 years, At 3 years, At 4 years, At 5 years

    The need for supplemental glaucoma medications will be reported as the number of glaucoma medications used

Sponsors and collaborators

Lead sponsor

University of Miami

Other

Collaborators

  • Abbott Medical Optics
  • National Eye Institute (NEI)
  • Research to Prevent Blindness

Registry information

Important dates

Study start
2008
Primary completion
2021
Study completion
2021
First posted
Apr 24, 2008
Registry last updated
Oct 19, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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