The Histology of Graft Adhesion in Descemet Stripping with Automated Endothelial Keratoplasty

1. The Histology of Graft Adhesion in Descemet Stripping with Automated Endothelial Keratoplasty Matthew Caldwell, Alan Proia, Francis DeCroos, and Natalie Afshari Duke Eye Center Authors have no financial interest. Supported by an award from Research to Prevent Blindness

2. PURPOSE • BACKGROUND • DSEK is the surgery of choice for endothelial dysfunction. • The most common complication is graft detachment. • The mechanism of graft adhesion is poorly understood. • OBJECTIVE • To describe the histologic findings of graft adhesion in DSEK 2

3. METHODS • IRB approval • Search of DSEK surgeries followed by PK • Clinical history reviewed • Slides cut and stained with • H&E • PAS • Colloidal Iron

4. RESULTS Eyes with PK following DSEK } Pseudophakic=10 (ACIOL=2) All high risk patients with multiple ocular comorbidities Glaucoma w/ tube = 5 Failed graft prior to DSEK = 6

5. Interface Findings • The interface was barely perceptible in most cases. Keratocyte density was unaltered at the interface. • In 3 cases, increased cellularity was noted along the unopposed stromal edge in areas of detachment.

6. Interface Material • Pigment granules and debris were seen in the interface to some extent in nearly all cases. The presence of glycosaminoglycans was not demonstrated with colloidal iron stain. 6

7. Interface Descemet Membrane • Descemet membrane was present in the peripheral interface in 8 of 10 cases.

8. Completely • Attached • (4/10) • +DM in 4/4 • More adherent to graft at split edges • Partially • Separated • (3/10) • +DM in 2/3 • More adherent to graft in 1, free floating in the other Interface Descemet Membrane Completely Separated (3/10) +DM in 2/3 • Adherent only to graft in both Of the 10 specimens, 4 were completely attached grossly, 3 were partially separated, and 3 were completely separated. Interface Descemet membrane (DM) was noted in all three groups. In all groups the interface DM was preferentially adherent to the graft rather than the posterior stroma.

9. Peripheral Splitting Artifact Peripheral splitting was present at at least one edge of all attached cases. This is presumed artifact due to shearing forces from specimen sectioning. This was present independent of the presence of Descemet membrane. Peripheral splitting artifact. Note preferential adhesion of Descemet membrane to the graft.

10. Other Findings Other anterior and posterior findings unrelated to the interface were present in many cases. • Fibrocollagenous pannus • Anterior stromal scarring • Paucity of endothelial cells • Retrocorneal membrane Retrocorneal membrane

11. CONCLUSIONS • DSEK grafts form adhesion without scarring or keratocyte proliferation. • Pigment granules and Descemet membrane are common in the interface. • DSEK grafts form a firm attachment to Descemet membrane (relative to the adhesion of DM to the native posterior stroma) • Stripping of Descemet’s membrane may be unnecessary for graft adhesion