The Cologne-Mecklenburg-Vorpommern DMEK Donor Study (COMEDOS) — design and review of the influence of donor characteristics on Descemet membrane endothelial keratoplasty (DMEK) outcome

Abstract

Background Posterior lamellar keratoplasty and especially Descemet membrane endothelial keratoplasty (DMEK) are gaining interest worldwide. Little is known about the influence of donor factors on DMEK outcome. Here we provide an overview of the existing peer-reviewed literature on this topic and present the design of the upcoming cooperation study COMEDOS (Cologne-Mecklenburg-Vorpommern DMEK Donor Study). Methods A literature search of PubMed and MEDLINE was conducted to retrieve articles published between September 2013 and May 2021. Seventeen peer-reviewed articles were selected. Design and concept of the prospective COMEDOS are outlined. Results Main interest parameters were the donor diabetes mellitus status, age, and lens status. There is a large heterogeneity regarding the sample size, study design, and investigated parameters. There seems to be a consensus that younger donors are associated with tighter rolls, a more difficult preparation, and unfolding setting. Diabetic donors seem to increase the risk of tissue tearing due to adherences and result more frequently in preparation failure. The COMEDOS aims not only to analyze the diabetes status of the donor, but also to correlate all donor systemic comorbidities and their ophthalmologic history to the DMEK clinical outcome. Furthermore, a correlation of Descemet membrane lamella preparation and surgery outcome is planned. Conclusion Currently, there is a lack of knowledge regarding the effect and impact of donor tissue characteristics on DMEK outcome and complications. An in-depth investigation is planned by the upcoming COMEDOS to close this knowledge gap.

Unaddressed Factors and Their Role in Descemet Membrane Endothelial Keratoplasty Outcomes: Comments on “Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty Using a Preloaded Imported Graft”

“…Younger graft donors (typically under 50 years) provide healthier endothelial cells and a higher ECD preoperatively and postoperatively offering better visual outcomes. 3 Although older donors may still be suitable, the grafts are stiffer, requiring more intraoperative manipulation leading to lower ECD and higher rebubbling and failure rates. 3 Donor comorbidity is a critical factor influencing graft performance.…”

“…3 Although older donors may still be suitable, the grafts are stiffer, requiring more intraoperative manipulation leading to lower ECD and higher rebubbling and failure rates. 3 Donor comorbidity is a critical factor influencing graft performance. Diabetes reduces donor ECD and graft preparation is more difficult, potentially causing more endothelial cell damage; ultimately, fewer endothelial cells are transplanted, leading to poorer patient outcomes.…”

“…4 Other donor characteristic factors that can affect DMEK success not considered in this paper include previous cataract surgery, race, and gender. 3 Preparation and transportation timings are critical to DMEK outcomes. The authors neglect to mention the graft peel time, a shorter peel time reduces the exposure of endothelial cells to potential damage affecting graft outcomes.…”

Influence of Descemet Membrane Endothelial Keratoplasty Graft Preparation Patterns on Postoperative Clinical Outcome

“…8,11,12 However, there is still a gap of knowledge regarding the influence of preparation factors on DMEK clinical outcome. 13 The aim of this study is to analyze the DMEK graft preparation challenges and describe the correlation to the patients' postoperative 1-year clinical outcome. information regarding the preparation of the DMEK graft, 85 because of insufficient follow-up, 8 eyes because of tissue losses, and 113 eyes because of poor visual potential.…”

“…8,11,12 However, there is still a gap of knowledge regarding the influence of preparation factors on DMEK clinical outcome. 13 The aim of this study is to analyze the DMEK graft preparation challenges and describe the correlation to the patients’ postoperative 1-year clinical outcome.…”