Intraocular Pressure Control and Corneal Graft Survival After Implantation of Ahmed Valve Device in High-Risk Penetrating Keratoplasty

Purpose: To analyze the control of intraocular pressure (IOP) and corneal graft survival after implantation of Ahmed glaucoma device (AGD) in eyes that had high-risk penetrating keratoplasty (PK). Methods: This is a retrospective noncomparative case series of 59 eyes that had high-risk PK and underwent AGD insertion. The primary outcome measures are the control of IOP between 6 and 21 mm Hg and corneal graft survival. The secondary outcome measures are risk factors associated with IOP control and corneal graft survival. Results: The mean IOP reduced significantly after the AGD procedure (26.45 +/- 6.8 mm Hg preoperatively vs. 16.85 +/- 7.4 mm Hg, 16.95 +/- 4.6 mm Hg, 17.97 +/- 5.7 mm Hg, 15.78 +/- 5.2 mm Hg, and 15.59 +/- 5.5 mm Hg, at 1 month, 6 months, 1 year, 2 years, and at the last follow-up postoperatively; P < 0.0001). Over a median follow-up of 78 months (range, 9-175 months) after AGD insertion, IOP control was successful in 44 eyes (75.8%). IOP control was successful in 96% of the eyes at 1 year, 87% at 2 years, 83% at 3 years, and 83% at 5 years. The percentage of clear corneal grafts after 1, 2, 3, and 5 years following the AGD insertion were 87%, 77%, 65%, and 47%, respectively. Further surgery after AGD insertion was associated with 1.79 times greater risk of failure of IOP control. Conclusions: AGD was effective in controlling the IOP associated with high-risk PK over a 5-year period. Postvalve surgery doubles the risk of failure of IOP control.