Materials and Methods: Data of 46 patients (48 eyes) with PK who underwent trabeculectomy for medically uncontrolled elevated intraocular pressure (IOP) were reviewed retrospectively from patient charts.

Results: At post-operative 24 months, trabeculectomy failed to control IOP despite additional anti-glaucomatous medications in 11 eyes (22.9%). IOP was under control with medications in 10 eyes (20.8%) and without medications in 27 eyes (56.3%). Cumulative probability of surgical success was 91.7% at 3 months, 89.6% at 6 months, 82.5% at 9 months, 80.2% at 12 months, and 74.8% at 18 months in the whole sample. Previous graft failure (odds ratio = 9.4, p = 0.009) and initial corneal diseases other than keratoconus/dystrophies (odds ratio = 6.8, p = 0.081) were the most likely associated preoperative risk factors for trabeculectomy failure. Survival rates in eyes with previous corneal graft failure, pseudophakia/aphakia, previous ocular surgery, or initial corneal diseases other than keratoconus/dystrophies were lower than their counterparts (p = 0.004, 0.230, 0.124, and 0.049 respectively). Cumulative probability of surgical success in eyes without these risk factors was 100% at postoperative 24 months, while it was 67.7% in eyes with at least one risk factor (p = 0.054).

Conclusions: Previous graft failure and initial corneal diagnosis are the most likely associated preoperative risk factors with trabeculectomy failure in eyes with PK. Alternative surgical procedures may be considered especially in eyes with a history of previous corneal graft failure. Keywords : Penetrating keratoplasty, glaucoma, elevated intraocular pressure, trabeculectomy