"Bubble-in-the-Roll" Technique Using the Endoject DMEK Injector: Influence of the Air Bubble on Endothelial Cell Loss.

PURPOSE: To evaluate the impact of the air bubble on endothelial cell loss using the "bubble-in-the-roll" technique during Descemet membrane endothelial keratoplasty (DMEK). METHODS: Twenty DMEK grafts not suitable for transplantation were manually prepared from organ-cultured corneoscleral discs and injected into culture media using the Endoject DMEK injector (Medicel AG, Wolfhalden, Switzerland). Based on the injection method, the grafts were divided into 2 groups: In group A (n = 10), a small air bubble was placed inside the graft roll while it was in the injector. In group B (n = 10), the grafts were injected without an air bubble inside the graft roll. Main outcome measures included endothelial cell density (ECD) after graft stripping and graft injection. RESULTS: There were no statistically significant differences between groups A and B in donor age, storage duration, and donor ECD. ECD decreased from 1929 ± 145 cells/mm to 1796 ± 303 cells/mm after graft stripping in group A and from 1801 ± 226 cells/mm to 1709 ± 290 cells/mm in group B. ECD after graft injection further decreased to 1683 ± 291 cells/mm in group A and to 1651 ± 292 cells/mm in group B. Endothelial cell loss after graft stripping and graft injection was not statistically significant between groups A and B (P = 0.29 and P = 1, respectively). CONCLUSIONS: The bubble-in-the-roll technique for injection and unfolding of the graft is a safe method for graft delivery into the anterior chamber guaranteeing orientation of the graft without harming the endothelium.

Reproducibility of graft preparations in Descemet's membrane endothelial keratoplasty.

PURPOSE: To assess the reproducibility of manual graft preparation and evaluate the incidence rate and nature of structural anomalies of Descemet's membrane (DM) preventing successful graft preparation in DM endothelial keratoplasty (DMEK). DESIGN: Prospective, single-center, nonrandomized, consecutive case series. PARTICIPANTS: We analyzed 350 corneoscleral buttons from donors aged 18-95 years stored in Optisol-GS or Dulbecco's modified Eagle's medium and used for DMEK surgery in 343 consecutive patients with Fuchs' endothelial dystrophy or pseudophakic bullous keratopathy. METHODS: Residual endothelial cell-DM complexes obtained after successful DM stripping for DMEK and whole donor corneas obtained after unsuccessful DM stripping were examined by transmission electron microscopy and immunohistochemistry. MAIN OUTCOME MEASURES: Accuracy of the cleavage plane between DM and corneal stroma and structural abnormalities of the DM-stroma interface. RESULTS: Uneventful manual separation without any disruption of DM was achieved in 335 of 350 donor corneas (95.7%) by use of a previously established bimanual submerged preparation technique. Correspondingly, the peeled DM specimens revealed a regular and smooth cleavage plane exposing the amorphous interfacial matrix on their anterior surface. Although 8 of 350 donor corneas (2.3%) showed focal adhesions of DM to the corneal stroma and developed isolated tears during stripping, preparation of the graft could be successfully completed. However, 7 of the 350 donor corneas (2.0%) showed extremely strong adhesion and multiple tears of DM, preventing successful preparation of the graft. These specimens revealed either ultrastructural (peg-like interlockings) or biochemical abnormalities (increased staining intensities for adhesive glycoproteins) along the DM-stroma interface. CONCLUSIONS: Using an appropriate technique, manual preparation of grafts for DMEK with reproducible tissue qualities is possible in the vast majority (98%) of donor corneas. Although a relatively rare phenomenon, interindividual variations in DM structure and composition may be responsible for failure of graft preparation in about 2% of donor corneas. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.