Epithelial downgrowth after penetrating keratoplasty: imaging by high-resolution optical coherence tomography and in vivo confocal microscopy.

PURPOSE: To report the clinical utility of high-resolution anterior segment optical coherence tomography (AS-OCT) combined with in vivo confocal microscopy (IVCM) to diagnose and follow the effectiveness of treatment of 2 cases of epithelial downgrowth after penetrating keratoplasty.

METHODS: A retrospective case review was performed on 2 eyes of 2 patients with a history of multiple penetrating keratoplasties that developed epithelial downgrowth 4 and 6 months after the most recent penetrating graft. At various time points, high-resolution AS-OCT images were obtained using the Spectralis (Heidelberg Engineering GmbH), and IVCM images were obtained using the Heidelberg Retina Tomograph III Rostock Cornea Module (Heidelberg Engineering GmbH). In 1 case, the diagnosis was confirmed by histopathologic evaluation.

RESULTS: Two patients developed epithelial downgrowth after penetrating keratoplasty. In case 1, a 48-year-old man with a history of Acanthamoeba keratitis developed epithelial downgrowth after undergoing 2 therapeutic grafts over a 1-year period. In case 2, a 40-year-old man with a history of a corneal laceration complicated by fungal keratitis was diagnosed with epithelial downgrowth after undergoing 3 penetrating grafts, the placement of a glaucoma drainage device, and a pars plana vitrectomy over a 3-year period. In both cases, at the level of the endothelium, AS-OCT identified a highly reflective layer and IVCM revealed round hyperreflective nuclei consistent with epithelium.

CONCLUSIONS: Epithelial downgrowth is an uncommon complication after penetrating keratoplasty. High-resolution AS-OCT and IVCM are noninvasive imaging modalities that may potentially be more sensitive in identifying and monitoring epithelial downgrowth than routine light biomicroscopy and may obviate the need for invasive diagnostic measures.