Abstract
Purpose: :
To investigate whether a transparent tissue layer partially covering the anterior surface of the Boston type I Keratoprosthesis front plate in four patients represents bona fide epithelium. Presence of this tissue could signify biointegration of these sight saving devices whose use has historically been complicated by infection and tissue necrosis.
Methods: :
In two cases, the tissue over the front plate was easily scrolled back as a single transparent layer using a sponge. This was removed several times and each time regrew in the same configuration within one month. Visual acuity was unchanged after removal. Microscopic analysis was undertaken and immunofluorescent staining against cytokeratin 3, specific to corneal epithelium in the eye, was performed.
Results: :
Microscopic analysis of samples from two patients revealed the tissue to be multi-layered, non-keratinized squamous epithelium. No goblet cells were seen, suggesting the cells were of corneal, and not conjunctival, epithelial origin. Immunofluorescent staining of all cells was positive for cytokeratin 3, signifying corneal epithelium.
Conclusions: :
The demonstration of the growth of regenerating, multi-layered, non-keratinized squamous corneal epithelium on the keratoprosthesis front plate represents a novel aspect of biointegration with potential ramifications for clinical outcomes. A device over which there is an intact epithelial layer would be expected to decrease the risk of endophthalmitis and tissue necrosis associated with permanent keratoprosthesis. Advances in keratoprosthesis composition, design, and surface modifications may be used to elucidate the surface epithelialization mechanism and to accelerate this process to improve outcomes.
Keywords: keratoprostheses • cornea: epithelium • cornea: clinical science