Secondary Graft Failure After Descemet Membrane Endothelial Keratoplasty: Clinical Characteristics and Ultrastructural Findings of Failed Grafts.

PURPOSE: To determine the clinical and ultrastructural characteristics of secondary graft failure after Descemet membrane endothelial keratoplasty (DMEK).

METHODS

Retrospective, single-center case series of eyes with failed DMEK grafts undergoing repeat DMEK between January 2014 and December 2023 at the Department of Ophthalmology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany. Potential risk factors for graft failure were correlated with the interval between the primary and repeat DMEK. Transmission electron microscopy (TEM) of excised Descemet membranes was used to detect ultrastructural alterations related to secondary graft failure after DMEK.

RESULTS

Among 6268 DMEKs, 156 cases (2.5%) met study inclusion criteria of secondary graft failure after an initial DMEK. Mean interval to repeat DMEK was 40 ± 30 months (range 5-132 months). Approximately 44% (n = 68) of eyes undergoing repeat DMEK had required air injections after the first DMEK because of graft detachment, compared with 10% in the primary DMEK cohort (P < 0.001). Glaucoma was present in 33% (n = 51) of eyes with secondary graft failure compared with 8% of our primary DMEK cohort (P < 0.001). Among the 51 glaucoma cases, 61% had primary open-angle glaucoma, 31% pseudoexfoliation glaucoma, and 8% chronic angle-closure glaucoma.TEM revealed the formation of a posterior collagenous layer more frequently in glaucoma eyes (92.5%) than in nonglaucoma eyes (76.5%). Posterior collagenous layer was significantly thicker in eyes with glaucoma.

CONCLUSIONS

Eyes with secondary graft failure exhibited a higher prevalence of glaucoma and rebubbling procedures after the primary DMEK. TEM findings suggest that pressure-independent mechanisms might contribute to graft failure in glaucomatous eyes.