Clinical Factors Impacting Outcomes From Failed Trabeculectomy Leading to Glaucoma Drainage Device Implantation and Subsequent Penetrating Keratoplasty.

PRECIS: We evaluated the factors that impacted time from GDI surgery to PK in eyes with previously clear corneas (i.e., GDI-first sequence), and that specifically underwent a trabeculectomy prior to GDI surgery for intraocular pressure control.

PURPOSE: To describe through an event-triggered data collection method the clinical course and the long-term outcomes of 2 procedures that are commonly performed sequentially in complex clinical situations: glaucoma drainage implant (GDI) surgery and penetrating keratoplasty (PK). The study investigates the clinical factors associated with progression to PK and determines the GDI success rate and graft survival.

METHODS: A single, tertiary-care center retrospective interventional cases series including patients with a sequential history of trabeculectomy, GDI surgery, and PK from 1999 to 2009. Outcome measures included intraocular pressure (IOP), visual acuity, graft failure, GDI failure, and time from GDI to PK.

RESULTS: 56% of eyes had primary open-angle glaucoma. The time from the last trabeculectomy to GDI was 66.5 +/- 66.7 months. 84% of eyes received a Baerveldt GDI. Time from GDI to PK was 36.4 +/- 28.4 months. IOP at the time of PK was between 5-21 mmHg in 90% of eyes. At the last follow-up, 48% of grafts were clear. At 5 years post-PK, 33% of corneal grafts remained clear, while 81% of tubes remained functional.

CONCLUSIONS: Nearly half of the corneal grafts are clear at the last long-term follow-up. Graft failure occurs at a higher rate than tube failure suggesting that IOP control is only one and possibly not the most important factor in graft survival in eyes with prior glaucoma surgery.