Same-quadrant Baerveldt Glaucoma Implant-250 to Baerveldt Glaucoma Implant-350 exchange

In eyes with a prior failed aqueous shunt (or "tube") requiring additional intraocular pressure (IOP) control, options include angle surgery, cyclodestruction, second tube, tube revision, or tube exchange. We present a case of a same-quadrant tube exchange of a Baerveldt-250 (BGI-250) to BGI-350.

The patient is a 71-year-old African American female with severe-stage primary open angle glaucoma of both eyes, and this case focuses on the right eye. This eye had prior cataract surgery with iStent, prior BGI-250 in the anterior chamber (AC), and prior iStent removal with gonioscopy assisted transluminal trabeculotomy (GATT). The visual acuity (VA) was 20/150, and the IOP was 26 mmHg on 3 IOP-lowering medications. The prior superotemporal BGI-250 had its "wings" on top of the superior and lateral rectus muscles and its tube tip in the AC. The implant was removed in its entirety including the superficial and deep layers of its capsule. The new BGI-350 was stented with a 3-0 polypropylene ripcord, ligated with a 7-0 polyglactin suture, and implanted with its wings under the rectus muscles and the tube tip in the sulcus. For early IOP-lowering prior to ligature dissolution, 2 needle stab fenestrations and an additional 7-0 polyglactin wick was used. The capsule from the prior BGI-250 was used as a patch graft for the new BGI-350. The ligature dissolved at postoperative week (POW) 6. By POW8, the IOP was 18 mmHg on 3 IOP-lowering medications and frequent topical steroid, the AC was quiet, and the ripcord was removed. A slow steroid taper finished at postoperative month (POM) 6. By POM 12, the VA was still at baseline 20/150, and the IOP was 14 mmHg on 3 IOP-lowering medications.

Patients with a prior failed tube requiring additional IOP-lowering can undergo a same-quadrant tube exchange. BGI-350s may offer more IOP-lowering than BGI-250s, but the IOP-lowering achieved in this patient's case could be attributable to differences in postoperative management in addition to endplate size; longer follow-up is needed. A tube exchange offers the opportunity to reposition the tube tip from the AC to the sulcus and to use the prior tube's capsule as a patch graft for the new tube.