LAMELLAR KERATECTOMY COMBINED WITH DESCEMET MEMBRANE ENDOTHELIAL KERATOPLASTY (DMEK) FOR SIGNIFICANT CORNEAL FIBROSIS AND CHRONIC CORNEAL EDEMA IN EYES WITH CORNEAL ENDOTHELIAL DISEASE: A CASE SERIES

To describe the feasibility of anterior lamellar keratectomy combined with Descemet membrane endothelial keratoplasty (DMEK) in a series of eyes with endothelial dysfunction and corneal scarring.

Tertiary referral center

Retrospective analysis of eight consecutive eyes of eight patients with a significant corneal scar from endothelial dysfunction, i.e. bullous keratopathy (BK) due to uveitis and glaucoma (n=1), primary DMEK transplant failure (n=1), pseudophakic BK (n=1), BK in the presence of an anterior chamber IOL (n=1), BK for ocular trauma (n=2) of which one patient had also received an artificial iris, BK for ICE-syndrome (n=1) and failed penetrating graft following pseudomonas keratitis (n=1). All eyes were evaluated with slit-lamp biomicroscopy and anterior segment optical coherence tomography (AS-OCT) and AS-OCT-based-pachymetry before surgery and up to 12 months postoperatively. In Cases 2-8, the removed corneal scarred tissue was investigated histologically.

All eyes showed a variable degree of corneal scarring and edema obscuring visualization of deeper ocular structures. Visual acuity ranged finger counting to handmotion in 7 patients, one patient with a penetrating trauma had no light perception, surgery was performed to reduce pain perception from BK. Before surgery, central pachymetry measured approximately between 800µm, and  1800µm in all patients. AS-OCT revealed a hyperdense compact layer  between epithelium and stroma suggesting a subepithelial location of the scar. Surgical removal of the subepithelial tissue was feasible in all eyes, improving visualisation for DMEK surgery. Histopathology confirmed dense fibrotic tissue underneath the epithelium with or without additional edema (Cases 2-8). Except for the patient with missing light perception that remained stable after surgery, visual acuity improved in all other eyes (finger counting to 20/50). Pachymetry normalized in most cases.The cornea of cases 1 and 2 cleared completely, while  the other corneas are still clearing up. The patient with the penetrating trauma and artificial iris developed an allograft rejection that was treated with intensified topical steroids.

Longstanding corneal edema from endothelial dysfunction may induce a dense corneal fibrosis  that may imply the necessity for penetrating keratoplasty to restore vision. Preoperative AS-OCT, may reveal a subepithelial rather than stromal fibrosis that can be successfully seperated from the corneal stroma and hereby make also such eyes accessible for  DMEK.