Histopathologic Analysis of Explanted KAMRA Corneal Inlays Demonstrating Adherent Fibroconnective Tissue Scar Formation

Abstract

Objective: To investigate the histologic composition of opaque membranes associated with corneal intrastromal inlays implanted for the surgical treatment of presbyopia. Methods: This is an observational case series of KAMRA corneal inlays explanted due to the presence of adherent opaque membranes associated with peri-inlay corneal stromal haze and sent for histopathologic analysis. Routine histology was performed in addition to immunohistochemical staining with myofibroblast and keratocyte markers. Results: Eleven explanted inlay specimens were received, of which, after histologic processing, four demonstrated suf­ficient cellular material for histopathologic analysis. The opaque membranes surrounding the explanted inlays were composed of fibroconnective tissue, and myofibroblasts (positive for smooth muscle actin immunostain) were the predominant cell type. Immunostaining for the keratocyte marker CD34 was negative, confirming that the membranes were the result of a reactive scar-tissue formation process and not simply normal corneal stroma adherent to the explant. Conclusions: Corneal inlay implantation can lead to the formation of an adherent fibroconnective tissue membrane, suggesting keratocyte-to-myofibroblast transdifferentiation and reactive fibroconnective tissue scar formation that could potentially impact visual potential. Prospective patients should be counseled regarding the risk of this complication, as this may be associated with some risk of incomplete reversibility of the procedure.