Corneal Graft Survival And Glaucoma Surgery Success In Patients With Prior Corneal Transplantation: A Retrospective Cohort Study

This study aims to evaluate different surgical strategies for the treatment of glaucoma in patients with previous full thickness and lamellar corneal transplantation (CT).

Corneal transplantation may exacerbate existing glaucoma or induce new-onset glaucoma. In addition, glaucoma and elevated intraocular pressure (IOP) are recognised as significant risk factors for corneal graft failure. Consequently, the management of coexisting corneal graft and uncontrolled glaucoma is challenging. Surgical intervention may be required to control IOP in the setting of prior CT.

Retrospective cohort study was conducted on all patients who underwent glaucoma surgery following CT at our institution between 2020 and 2023. Corneal graft survival and glaucoma surgery success were the outcomes sought 6 months after glaucoma surgery. Patient demographics, cause and type of CT, history of previous graft rejection, history of previous glaucoma, cause of post-transplant glaucoma, type of glaucoma procedure, pre CT and pre- and post-glaucoma surgery IOP at various intervals, reduction of hypotensive medication, complications, and cause of corneal graft rejection were obtained from medical records.

A total of twenty eyes were included. At month 6, glaucoma surgery success was achieved in 16 eyes (80%) and corneal graft survival reached 55%. The most frequent cause of corneal rejection was secondary non-immune (6/9, 66%). Corneal graft survival was significantly higher in the DNPS (3/3, 100%), XEN implant (2/2, 100%) and Paul implant subgroups (2/2, 100%) compared to Trabeculectomy (4/9, 44%) and Ahmed valve (0/4, 0%) (p=0.014). No significant differences were detected in corneal graft survival between groups according to previous graft rejection, age or gender. Success rates for glaucoma surgery showed no statistically significant differences according to type of glaucoma surgery procedure (p=0.84) and type of CT (p=0.50).

In refractory glaucoma secondary to CT, success rates of 80% at 6 months can be achieved with either trabeculectomy, DNPS, XEN or Paul tube surgery. However, we found graft survival appears to be greater in those patients undergoing DPNS, Xen stent or Paul implantation.