6
already in use) steroids preoperatively, an intraoperative intravenous dose of steroids, and a
higher postoperative topical dosing regimen.
Postoperative success was considered unqualified if glaucoma was controlled without
medications with intraocular pressure between 5-21 mmHg and no signs of progressive
glaucomatous damage as evidenced by cup/disc ratio measurements, progressive myopia,
increased corneal diameter, or corneal edema. Success required no visual loss of more than 2
Snellen-lines secondary to the implant. Success was deemed qualified if ocular anti-
hypertensive agents were necessary to maintain these criteria. Failures included any patient
whose glaucoma remained uncontrolled despite additional medial therapy, had the implant
removed due to complications, or suffered 2 or more Snellen-lines of visual loss.
Surgical technique
A limbal-based conjunctival flap was created in the superior temporal quadrant or
superior nasally (2 eyes in which the temporal quadrant was previously operated). Sclera
was exposed using blunt dissection. The tube was then primed using 1 ml of balanced salt
solution. The plate was secured to the sclera with its anterior edge 5-8mm posterior to the
limbus using two 6-0 Mersilene (Ethicon Inc. Summerville, NJ) or Ticron (Sherwood, Davis
and Check, St. Louis, MI) sutures. Partial tube ligation was accomplished using a single 6-0
Vicryl suture (Ethicon Inc. Summerville, NJ) that was passed through the sclera, partial
thickness, 2-3 mm in front of the plate, and then tied around the tube so that partial occlusion
was achieved. This was done in attempt to decrease the rate of early postoperative hypotony.
A self-sealing clear cornea paracentesis track was created inferiorly using a 25-guage needle.
The tube was trimmed bevel up so that it reached mid iris. A 23-gauge needle was used to
enter the anterior chamber at the surgical limbus aiming towards the center of the pupil. The
tube was inserted through this opening, and secured to the sclera using a pre-placed 10-0
