Deposition of a Descemet-like Layer by Ectopic Corneal Endothelium – Ultrastructure of a Long-term Persistent Double Anterior Chamber after Complicated Deep Anterior Lamellar Keratoplasty (DALK)

Introduction

Deep anterior lamellar keratoplasty (DALK) is a microsurgical approach for the selective removal of diseased corneal stroma with preservation of the patientʼs healthy endothelium. The main advantages over penetrating keratoplasty (PKP) are the absence of donor endothelium as a potential immune target, the preservation of endothelial cell density, especially in young patients, and the avoidance of open-sky complications [1], [2], [3]. However, interface clarity, and thus visual outcome, after DALK depends on the preparation of a thin, smooth and uniformly thick recipient bed [4], [5]. This requires deep stroma dissection, which carries the DALK-specific risk of unintentional perforation of the underlying recipientʼs Descemetʼs membrane (DM). In this case, the recipient bed is likely to be separated from the graft by the leaking aqueous humor, resulting in the formation of a so-called “double anterior chamber” (AC), with aqueous flow on either side of the detached host layer [6]. For reattachment of the layer and coverage of the leak, the tamponade with gas (rebubbling) is usually a sufficient treatment. In case of a persistent double AC, the surgical correction by PKP may be necessary [7].

Some DALK surgeons decide to not remove DM and endothelium of the donor lenticule in order to preserve the regularity of the posterior donor surface and to reduce mechanical trauma of the tissue during the preparation (so-called “donor Descemet-on DALK”). This practice, however, is likely to delay the healing process of the interface, to increase interface reflectivity, and to promote the persistence of a potential double AC [8], [9]. Moreover, the transplanted donor endothelium remains a potential target of immunological rejection, which neutralizes one of the main advantages of DALK. The majority of current DALK protocols advise the removal of the donor DM and endothelium [4], [10].

This article reports on a patient who developed a double AC after complicated Descemet-on DALK, which then presumably persisted for 12 years. This unusual constellation as well as the long period enabled adaptation processes of the co-transplanted donor endothelium to the microenvironment of the double AC. An excimer PKP was performed, and the excised tissue was examined by light and transmission electron microscopy (TEM).

Publication History

Received: 24 November 2024

Accepted: 06 February 2025

Article published online:
27 March 2025

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