Deep anterior lamellar keratoplasty: challenges in histopathological examination.

Abstract

To characterise histopathological changes in corneal buttons associated with deep anterior lamellar keratoplasty (DALK). This was a retrospective, clinical laboratory study. All recipient corneal buttons that underwent DALK in the West of Scotland and were submitted to the regional Ocular Pathology Laboratory (Glasgow, UK) between 2001 and 2010 were examined. Cases affected by artefacts secondary to DALK were highlighted. Keratoconus cases that underwent DALK were compared to those that underwent penetrating keratoplasty (PK). 225 DALK corneal buttons were examined. Of these, 61.8% were affected by artefacts or problems related to DALK. Overall, 58.2% of the affected buttons were affected by corneal emphysema related to intrastromal air injection (the 'big bubble' technique), 5.3% by epithelial oedema related to the hydrodelamination procedure, which mimicked bullous keratopathy secondary to endothelial cell deficiency, and 0.9% were lost specimens. We were not able to identify any conus, which is a characteristic histopathological feature of keratoconus, in 10 (7.4%) of the DALK-keratoconus cases as opposed to two (1.6%) of the PK-keratoconus cases (p=0.036). DALK poses new challenges for histopathological examination of corneal buttons. Awareness of DALK-related histopathological characteristics should be raised among ocular pathologists and ophthalmologists in view of the increasing popularity of this technique.