Epithelial Downgrowth Mimicking Recurrent Retroprosthetic Membrane After Boston Keratoprosthesis Implantation.
Sandy Samuel, Ari August, Tatyana Milman et al.
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Case in brief
A 74-year-old monocular man with prior penetrating corneal injury, multiple failed corneal transplants, and a Boston type 1 keratoprosthesis developed reduced vision and opaque material behind the device’s optical element. It was interpreted as a retroprosthetic membrane; YAG laser membranectomy repeatedly restored vision to baseline, but the membrane recurred in less than 7 days. Because frequent visits were required, the patient requested KPro removal and replacement with a corneal allograft. Histopathology showed stratified, nonkeratinizing squamous epithelium on the posterior carrier cornea and optical element, consistent with epithelial downgrowth.
What made this case unusual
Epithelial downgrowth presented as an apparent retroprosthetic membrane, with unusually rapid recurrence after each laser membranectomy.
Diagnostic / clinical pearl
Consider epithelial downgrowth when a retroprosthetic membrane recurs frequently and rapidly after membranectomy in an eye with a Boston keratoprosthesis; histopathology may establish the diagnosis.