Alternative to Penetrating Keratoplasty

Endothelial keratoplasty (EK) has become the standard of care for the surgical management of endothelial dysfunction. And when it comes to choosing an EK procedure, Jennifer Rose-Nussbaumer MD relies on Descemet membrane endothelial keratoplasty (DMEK) as the workhorse for the majority of her patients.

However, Ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) has an important role for select eyes with endothelial dysfunction, and some patients may even be candidates for Descemet stripping without EK (aka, Descemet stripping only [DSO]), Dr Rose-Nussbaumer said.

DSO eligibility

Descemet stripping only can be considered an option for patients with Fuchs’ corneal endothelial dystrophy having only central guttata (<4.5 mm) and a good peripheral endothelial cell count (≥1000 cells/mm²). Dr Rose-Nussbaumer observed the availability of imaging technology (CellChek 20 PLUS, Konan Medical) affording visualisation of the endothelium in the peripheral cornea enables her selection of patients for DSO.

Although technically a straightforward procedure, there are two keys to achieving success. To enable cell migration and proliferation, surgeons must incorporate as many guttata as possible and be careful to avoid disrupting the stroma.

Adjuvant use of a rho kinase inhibitor appears to improve DSO outcomes, although ripasudil, which is commercially available only in Japan, seems more effective than Europe and US-approved netarsudil. Further studies of netarsudil are underway. In the meantime, Dr Rose-Nussbaumer said ripasudil can be readily acquired through online sources.

DMEK vs UT-DSAEK

Although technically more difficult than UT-DSAEK, DMEK has an advantage of allowing faster and better visual recovery. As a tip for surgeons performing DMEK, Dr Rose-Nussbaumer noted controlling anterior chamber depth is important for enabling graft unfurling.

“Surgeons should modulate anterior chamber depth by allowing egress of fluid so that there is enough room for the graft to unfurl but not so much room for the graft to curl right back up,” she said.

Concern about greater endothelial cell loss over time after DMEK versus UT-DSAEK was raised in a randomised controlled trial conducted by Dr Rose-Nussbaumer and colleagues.¹ The difference between procedures was not statistically significant in prespecified models but was in a repeated measures analysis. An ongoing National Institutes of Health-funded trial is investigating if DMEK is still good for complex eyes and whether cell loss is higher in DMEK in general, which is important as it may reduce the longevity of the graft.

Dr Rose-Nussbaumer said she chooses UT-DSAEK in complex cases where difficulty with DMEK graft positioning is anticipated, such as in eyes with severe corneal scarring, aphakia, aniridia, or a scleral fixated IOL. She illustrated her point by presenting a patient who had sustained a traumatic injury leading to lens loss, implantation of a scleral-fixated artificial iris implant, and corneal oedema. The completed UT-DSAEK procedure used a pull-through technique with sutures to pull the graft into place. At six months postoperatively, the patient had 20/25 visual acuity.

If assistance is needed with visualisation during DMEK or DSAEK, Dr Rose-Nussbaumer said she has implemented anterior segment OCT or chandelier lighting.

“Inserting the chandelier is very straightforward, even for us as anterior segment surgeons, and has been a game-changer for me because it completely lights up the intraocular world,” she said.

Dr Rose-Nussbaumer spoke at ASCRS 2024 Cornea Day in Boston, US.

Jennifer Rose-Nussbaumer MD is Associate Professor of Ophthalmology, Stanford Byers Eye Institute, Palo Alto, California, US. rosej@stanford.edu

1. Chamberlain W, Lin CC, Austin A, et al. “Descemet Endothelial Thickness Comparison Trial: A Randomized Trial Comparing Ultrathin Descemet Stripping Automated Endothelial Keratoplasty with Descemet Membrane Endothelial Keratoplasty,” Ophthalmology, 2019; 126(1): 19–26.