Primary Tube Versus Trabeculectomy Study
Research to Prevent Blindness
Bascom Palmer Eye Institute

      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.
    
Procedure