DMEK Corneal Transplants Have Low Rejection Rates, Large Multicenter Study Shows

Patients who undergo Descemet membrane endothelial keratoplasty (DMEK) experience increased visual acuity and low transplant failure and rejection rates, according to a study published in Acta Ophthalmologica. Patients with Fuchs endothelial corneal dystrophy (FECD) typically have superior outcomes to those with bullous keratopathy (BK), researchers explain.

The retrospective multicenter study analyzed DMEK performed at 7 centers throughout Germany before August 2016. Participants had to have a minimum follow-up of 6 months after the procedure. The researchers collected visual acuities, corneal thicknesses, rebubbling rates, transplant failure rates, and immune reaction rates.

A total of 3200 DMEK procedures (mean patient age 71±10 years) were included in the study. The indication for surgery was FECD for 2574 patients (83.8%) and BK for 497 (16.2%) patients.

A quarter of cases had additional noncorneal ocular pathologies, potentially limiting visual acuity outcomes. But for the rest of the participants, mean best corrected visual acuity (BCVA) improved from 0.6±0.4 logMAR to 0.2±0.2 logMAR 6 months after surgery (n=1441; P <.001) and, after 12 months, to 0.1±0.2 logMAR (n=1402; P =.001).

While 784 eyes (25%) received at least 1 rebubbling, the investigation shows that a single rebubbling does not influence BCVA (P =.785). The mean rebubbling rate in this study was 0.4±0.7 per eye. More than 1 rebubbling correlates with a lower ECD, a worse BCVA, and higher failure rate, according to the researchers. Overall endothelial cell density declined at 1 year from 2465±259 cells/mm2 to 1587±433 cells/mm2 (P <.001)

The researchers report that the graft failure rate for DMEK overall is approximately 3% with a rejection rate of 1.5%. 

Patients with BK experience worse 1-year postoperative BCVA compared with patients with FECD (0.3±0.5 vs 0.1±0.2 logMAR; P <.001). 

“FECD patients achieved around 0.1 logMAR BCVA while BK patients only reached 0.3 logMAR 1 year after surgery,” the researchers explain. Prior research also shows BCVA in patients who undergo DMEK for FECD is, on average, 0.16 logMAR better than those who undergo DMEK for BK. “This can be explained by stromal corneal alterations resulting from prolonged corneal edema, which limits the visual acuity outcome after DMEK or complex ocular comorbidities associated with prior surgery.”

This study was limited in that no definition for transplant failure and immune rejection was presented, and researchers did not define at which detachment size a rebubbling was indicated. This was also a retrospective analysis, so the data assessment did not follow the same regimen at each center.