Confocal microscopy after implantation of intrastromal corneal ring segments

Abstract

Abstract Purpose To evaluate with in vivo confocal microscopy (IVCM) the corneal microstructure changes due to Intrastromal Corneal Ring Segments (ICRS; KERARING Mediphacos Inc., Belo Horizonte, Brazil) implantation. Methods Nine eyes of keratoconic patients were prospectively examined with the HRT 3 confocal microscope with the Rostock cornea module before and 1 month after ICRS implantation. Epithelial basal cell density, endothelial cell density and keratocyte density in the anterior, mid and posterior stroma were measured in the center of the cornea and around ICRS (approximately 3.5 mm off the center of the cornea). Results In the central cornea, we found normal morphologic features at all layers. In peripheral section (near the ICRS) epithelial basal cell density and endothelial cell density were unchanged. However, around the ICRS, keratocyte density increased in the mid stroma (6% increase) and in the posterior stroma (9% increase)(P<.05) but no increase was noticed in the anterior stroma (P=.13). This increase may be due to the best visualisation of activated keratocytes. Hyper‐reflective keratocyte nuclei are thought to indicate the presence of fibroblastic cells. Increased haze adjacent to the ICRS is found to be due to fibroblastic accumulation and irregular collagen fibres. Conclusion Whereas the central corneal zone appears unchanged, the corneal stroma adjacent to the ICRS displays a slight, but distinct, activation of wound healing. IVCM offers a potential insight into the pathophysiology of the microstructural changes in keratoconus after ICRS implantation.