Friedrich Kruse MD
Descemet’s membrane endothelial keratoplasty (DMEK) represents a clear advance over penetrating keratoplasty and other endothelial keratoplasty techniques in terms of safety and visual outcomes for certain indications, Friedrich Kruse MD told delegates attending the 8th EuCornea Congress in Lisbon.
“As surgeons we can all agree that the safety of the procedure is of the utmost importance for the patient. Studies by Price et al. and others have clearly shown that penetrating grafts and Descemet’s stripping endothelial keratoplasty (DSEK) with thicker grafts have a higher graft rejection rate compared to DMEK for at least up to two years postoperatively and I think this also holds true for a longer period,” he said.
Looking at data of 1,090 patients from the Cornea Donor Study (CDS), Dr Kruse said that the 10-year cumulative probability for the first definite rejection event was 15% and for the first definite or probable rejection event was 34%.
By contrast, Dr Kruse said that he was aware of just one case of DMEK graft rejection in more than 500 cases at his own clinical centre and other published studies have confirmed a very low rate of immunologic graft rejection up to several years after transplantation.
Dr Kruse’s own group recently published a long-term analysis of clinical outcomes after DMEK and concluded that the cumulative probability of five-year graft survival was 95%.
“The picture is very different in DMEK. This reduced risk of rejection means that we can now administer steroids for six months and then discontinue it and that also reduces the risk of secondary glaucoma,” he said.
Visual rehabilitation is typically rapid with DMEK procedures and the outcomes obtained are excellent, said Dr Kruse. In his own long-term study, corrected distance visual acuity improved from 0.62 logMAR before DMEK to 0.13 logMAR postoperatively, and 57% of eyes without ocular comorbidities attained 20/25 at five years after DMEK. Moreover, the visual acuity and endothelial cell loss remained stable between three months and five years after surgery.
One possible explanation for the excellent visual outcomes obtained in DMEK may lie in a reduced incidence of higher-order aberrations compared to penetrating keratoplasty and Descemet's stripping automated endothelial keratoplasty (DSAEK), said Dr Kruse.
Interestingly, a study by Tourtas et al. showed that aberrations of the corneal back surface decreased significantly in the first three months after DMEK and correlated with the rapid increase of visual acuity. However, during the third and fourth postoperative year, the aberrations of the corneal back surface increased again and afterwards remained stable through the fifth year, correlating with an increase in corneal thickness.
Corneal aberrations might therefore provide a more detailed analysis of optical quality after DMEK, said Dr Kruse.
Friedrich Kruse: friedrich.kruse@uk-erlangen.de
