Ab Externo Continuous Pressure Technique for Descemet Membrane Endothelial Keratoplasty in Vitrectomized Eyes

Descemet membrane endothelial keratoplasty (DMEK) in vitrectomized eyes presents a significant surgical challenge, as the compromised counter-pressure of the iris-lens diaphragm impedes proper shallowing of the chamber, making graft unfolding and centration challenging. To address this challenge, surgeons often pivot to Descemet's stripping automated endothelial keratoplasty. DMEK superior visual outcomes, fast rehabilitation and low rejection risk, have prompted the exploration of tailored DMEK techniques in vitrectomized eyes. This study describes a novel technique, which consists of continuous external pressure on the corneal surface while unfolding and orienting the graft.

A case series of 8 eyes from patients with an average age of 68 ± 13 who underwent DMEK surgery with the novel continuous pressure technique is described. Visual acuity outcomes and complications were assessed preoperatively and at 1-year follow-up. Data were analyzed using a Student t test.

All corneas cleared postoperatively and remained clear for the 12-month follow-up duration. Implementation of the continuous pressure technique allowed proper unfolding and centration of DMEK grafts in all of these challenging cases. Best-corrected visual acuity following surgery improved significantly from an average of logMAR 1.05 ± 0.12 to logMAR 0.3 ± 0.16 (p = 0.003) with no intraoperative complications. Three patients underwent re-bubbling (37.5%), and 1 patient had a graft failure 3 years following DMEK.

The ab externo continuous pressure technique for DMEK in vitrectomized eyes is effective and relatively easy to adopt. The technique requires no additional instrumentation and minimizes graft handling, offering a valuable option for managing these challenging cases.