What’s New in DMEK Procedures

Descemet membrane endothelial keratoplasty (DMEK) is the preferred procedure for treating endothelial disorders. However, a rise in endothelial keratoplasties is contributing to a global shortage of corneal tissue. During Saturday’s Cornea Subspeciality Day meeting, Isabel Dapena, MD, PhD, provided an overview of new DMEK techniques that may help meet patient and physician needs.

Over the years, several new DMEK techniques have arisen:

• Descemet stripping only (DSO). In DSO, a descemetorhexis is performed to stimulate endothelial cell migration. Since there is no transplant, this approach requires no corneal tissue for grafting and avoids the risk of rejection. However, visual recovery can be slow, and results vary among patients. Studies suggest that outcomes improve when a topical Rho kinase (ROCK) inhibitor is used, but larger studies with longer follow-up are warranted.
• Hemi- and quarter-DMEK. These approaches aim to facilitate more efficient use of donor tissues. The hemi procedure produces two half-moon nontrephined DMEK grafts from a single donor, while quarter-DMEK yields four grafts that can be used with a smaller descemetorhexis. Visual recovery with this method appears comparable to standard DMEK. However, one year after surgery, there can be an increase in endothelial cell migration. These grafts are also more likely to detach compared with circular tissue grafts.
• Custom DMEK. By customizing the descemetorhexis and graft diameter to a size that matches the patient’s condition, only the affected endothelium is replaced. This could better preserve peripheral host cells and reduce endothelial cell migration.

These procedures show promise but require further assessment to optimize outcomes and mitigate endothelial cell density loss. Improving the graft shape and size of descemetorhexis, and considering the severity of the disease may be key. —Kanaga Rajan, PhD

Financial disclosures: Dr. Dapena: None.