DALK for Spontaneous Posterior Corneal Layer Detachment in Recurrent Ectasia After Keratoplasty

PURPOSE: The aim of this study was to describe 3 keratoconic eyes referred for painless visual loss approximately 2 decades after penetrating keratoplasty, initially misdiagnosed as immunologic rejection but instead found to have detachment of a thin posterior corneal layer, which was successfully managed with deep anterior lamellar keratoplasty (DALK). METHODS: This retrospective case series was conducted at Villa Igea, Ospedali Privati Forlì (Forlì, Italy). The main outcomes were best spectacle-corrected visual acuity, imaging findings, and endothelial cell density (ECD). RESULTS: All patients presented with sectorial corneal edema extending into the host cornea, in the absence of intraocular inflammation. Anterior segment optical coherence tomography confirmed the extensive detachment of a thin posterior layer of the cornea, associated with ectatic thinning of the host stroma. Specular microscopy was possible in the nondetached area and showed a mean ECD of 1096 ± 235 cells/mm2. To simultaneously address both the detachment and the recurring ectasia, each patient underwent a 9.0-mm DALK with complete preservation of the detached layer, thus also capping the ectatic portion of the recipient bed. Postoperatively, all corneas remained clear with no subsequent edema, best spectacle-corrected visual acuity improved to 20/30 or better, and average ECD showed minimal decline. CONCLUSIONS: Detachment of a thin posterior layer from the grafted cornea in post-penetrating keratoplasty keratoconic eyes may mimic endothelial rejection. Sectorial corneal edema extending beyond the graft-host junction should prompt consideration of a mechanical rather than an immunologic etiology. This case series highlights the possibility of successfully handling both the recurrent ectasia and the detachment with a 9.0-mm DALK.