Impact of Prior Ahmed Glaucoma Valve Implantation on Surgical Success and Prognosis in Eyes Undergoing Keratoplasty

OBJECTIVES: This study aimed to evaluate the surgical outcomes and prognosis of patients who underwent Descemet membrane endothelial keratoplasty (DMEK) or penetrating keratoplasty (PK) following Ahmed glaucoma valve (AGV) implantation.
METHODS: Patients who underwent keratoplasty at the cornea department of our hospital between April 2016 and April 2024 were retrospectively reviewed. Patients with a history of prior AGV implantation were included. Surgical success was defined as maintaining graft clarity for a minimum of 6 months post-keratoplasty.
RESULTS: A total of 13 eyes of 13 patients (four women, nine men) with a mean age of 62.0±16.0 years were included. Five patients had a history of multiple glaucoma surgeries prior to AGV implantation. Among the included patients, six had no history of corneal transplantation before AGV implantation, whereas four had previously undergone PK, and two had undergone DMEK. One patient had received two DMEK procedures followed by PK. No tube-related complications, including endothelial touch, were observed. Corneal decompensation developed at a mean of 12.7±10.5 months after AGV implantation, prompting PK in four patients, repeat PK in five patients, and DMEK in four patients. The mean follow-up period after keratoplasty was 21.3±17.3 months. Although the best-corrected visual acuity (BCVA) achieved postoperatively was 1.5 (0.4–2.3) LogMAR at a mean of 13.9±12.3 months, there was no statistically significant difference between pre-operative BCVA (2.3 [1.0–2.3] LogMAR) and final post-operative BCVA (2.3 [0.4–2.7] LogMAR) (p=0.735). Similarly, no significant change was observed in intraocular pressure before and after keratoplasty (p=0.283). A second keratoplasty was recommended in five cases after the initial keratoplasty. At the final follow-up, graft rejection was observed in eight patients, two of whom developed keratitis. The overall surgical success rate was calculated as 23.1%.
DISCUSSION AND CONCLUSION: In patients undergoing keratoplasty for corneal decompensation following AGV implantation, both graft survival and overall surgical outcomes were found to be unfavorable.

Keywords: Ahmed glaucoma valve, Descemet membrane endothelial keratoplasty, Glaucoma, Graft survival, Keratoplasty