Endothelial Side Up Inverted Femtosecond Laser Assisted DSAEK

Endothelial Side Up Inverted Femtosecond Laser Assisted DSAEK a Pilot Study

To evaluate the clinical outcomes (pos toperative best corrected visual acuity, endothelial count) and anatomical results (interface smoothness) of DSAEK with Femto LDV-prepared grafts from the endothelial side.

Corneal transplantation is the most frequently performed transplant surgery worldwide, restoring visual function when corneal damage is severe. Traditionally, Penetrating Keratoplasty (PKP) was used to treat all forms of corneal blindness, but it comes with potential complications such as graft rejection, wound leaks, and astigmatism. To address these limitations, Endothelial Keratoplasty (EK) emerged as a less invasive alternative, particularly for conditions where only the corneal endothelium is compromised (e.g., Fuch's endothelial dystrophy and pseudophakic bullous keratopathy).

EK began with Posterior Lamellar Keratoplasty (PLK) and evolved through Descemet's Stripping Endothelial Keratoplasty (DSEK) and Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK), which uses a microkeratome to create a thin corneal graft. DSAEK, however, results in a meniscus-shaped graft with some degree of hyperopic shift postoperatively. Another advancement, Descemet's Membrane Endothelial Keratoplasty (DMEK), uses only the donor's Descemet membrane and endothelium, providing better visual outcomes and fewer rejection risks. Despite these benefits, DMEK is technically challenging and unsuitable for some complex cases.

Ultrathin (UT) DSAEK introduced sequential microkeratome cuts, achieving graft thickness below 100 µm. This approach offers faster visual recovery and comparable refractive outcomes to DMEK, but with higher perforation risks during graft preparation. Newer graft preparation methods, such as femtosecond laser-assisted techniques, have been introduced to improve consistency, though deeper femtosecond laser cuts sometimes reduce accuracy due to laser scattering.

This study proposes using Femto LDV (Ziemer Ophthalmic Systems AG) to prepare ultrathin DSAEK grafts from the endothelial side to ensure smoother interfaces and consistent graft thickness. Previous in-vitro studies indicate that these grafts offer better endothelial protection and less damage when coated with Viscoat (sodium chondroitin sulfate 4.0%-sodium hyaluronate 3.0%) compared to basic saline solution.

Study Aim The goal of this pilot study is to evaluate the clinical outcomes (best-corrected visual acuity, endothelial cell count) and anatomical outcomes (interface smoothness) of DSAEK with Femto LDV-prepared grafts.

Inclusion Criteria:

Patients with Fuchs' endothelial dystrophy Patients with bullous keratopathy secondary to intraocular surgeries, iridocorneal endothelial syndrome, or viral keratitis

Exclusion Criteria:

Bullous keratopathy secondary to glaucoma or ocular trauma Corneal stromal scarring or opacities Diseases not affecting the corneal endothelium, including corneal ectasia (e.g., keratoconus, keratoglobus, pellucid marginal degeneration) Epithelial, Bowman layer/anterior stromal, and stromal dystrophies Hypotonic eyes Retinal diseases Any type of optic atrophy