Pachymetry Mapping After DMEK Can Predict Graft Detachment

TRUJILLO, PERU – APRIL 18: Corneal edema aphakia patient Jose, aged 87, undergoes surgery at the IRO (Regional Institute for Ophthalmology) on April 18, 2018 in Trujillo, Peru. Following a clinical screening day, Jose was chosen for a penetrating keratoplasty procedure (cornea transplant) during a programme run by Orbis, the ophthalmic training organisation. Founded in 1982 by ophthalmologist David Paton, Orbis trains eyecare teams across Africa, Asia and Latin America to improve the standard of eyecare in the region. As well as working in local hospitals, the charity also has a self-sufficient surgical unit on the Orbis Flying Eye Hospital, a converted McDonald-Douglas MD10 aircraft. (Photo by Leon Neal/Getty Images)
Conducting the monitoring technique 1 day after surgery can reveal a patient’s potential for success, a report shows.

Conducting pachymetry mapping 1 day after Descemet membrane endothelial keratoplasty (DMEK) can help predict early graft detachment, according to findings published in Cornea. Increased local corneal thickness was also associated with detachment, the report shows. Investigators also built prediction models that demonstrated good to excellent performance, and could aid in identifying patients at risk for graft detachment, enabling tailored postoperative care. 

To evaluate the predictive value of pachymetry mapping 1 day after DMEK as a biomarker for early graft detachment, the investigators conducted a post hoc analysis of 65 pseudophakic adult patients with Fuchs endothelial dystrophy who underwent DMEK between December 2018 and April 2021. The study was part of the Advanced Visualization In Corneal Surgery Evaluation international multicenter randomized controlled trial (ClinicalTrials.gov Identifier: NCT03763721). 

Patients underwent anterior segment optical coherence tomography (AS-OCT) imaging (1 eye per patient) preoperatively and 1 day postoperatively. Pachymetry mapping using a grid comprising 25 zones, measurement of corneal thickness, and evaluation of graft detachment were conducted for each patient. The investigators developed 2 prediction models, a regression model and a model based on absolute corneal thickness.

A total of 65 eyes were analyzed. Of those, 33 eyes developed graft detachment. The mean time from surgery to detection of detachment was 7.54 days (range, 1-32). Preoperatively, no significant differences in corneal thickness was observed between the groups (P = .221). In corneal zones with a detached graft, corneal thickness was significantly increased compared with corneal zones with an attached graft (P < .001). 

The investigators demonstrated that the regression prediction model had an area under the curve of 0.87 (sensitivity, 0.79; specificity, 0.75), and the absolute corneal thickness cutoff model reached 0.65 (sensitivity, 0.63; specificity, 0.63).

Limitations of the study included that the post hoc analysis was part of a trial that was not powered for corneal thickness as an outcome measure; a considerable proportion of the corneal thickness measurements were missing; and 2 different imaging systems were used to measure corneal thickness.

Reference

Muijzer MB, Noordmans HJ, Delbeke H, et al. Establishing a biomarker for the prediction of short-term graft detachment after Descemet membrane endothelial keratoplasty. Cornea. February 19, 2022. doi:10.1097/ICO.0000000000003006