Confocal microscopy after implantation of intrastromal corneal ring segments

Objective: Confocal in vivo real-time microscopy was used to study the corn eal morphologic features in eyes after Intrastromal Corneal Ring Segments ( ICRS; now called KeraVision INTACS, KeraVision, Inc., Fremont, GA) implanta tion. Design: Noncomparative, interventional case series. Participants: The authors performed confocal real-time microscopy on a tota l of 21 eyes from 11 patients. Seventeen eyes from 10 patients (five female , five male; mean age 32.3 years; range 22-42 years) underwent uncomplicate d ICRS surgery to correct myopia and were examined after surgery (average 8 .6 months; range 2-15 months). Three patients had the ICRS implanted into o nly one eye, and those eyes were compared with the untreated fellow eyes. O ne eye of another patient was examined 1 and 6 months after ICRS removal. Intervention: Flying slit-confocal microscopy was performed with water imme rsion objectives in the corneal center and near the nasal or temporal ICRS. Corneal optical sections were recorded in real time without further digita l processing and were reviewed frame by frame. Main Outcome Measures: Video frames selected from all corneal layers were e valuated qualitatively and quantitatively. Results: In the central cornea, we found normal morphologic features at all layers. In peripheral sections, epithelial cells with highly reflective nu clei in the basal cell layer were observed in six of 17 eyes (35%) implante d with ICRS. We found an intact corneal nerve plexus and undisturbed cornea l endothelium immediately underneath the ICRS. Around the ICRS, moderate fi brosis was seen. In one eye, linear structures in bamboo-like orientation w ere detected after ICRS removal in the last keratocyte layer underneath the collapsed tunnel. Conclusions: Whereas the central corneal zone appears unchanged, the cornea l stroma adjacent to the ICRS displays a slight, but distinct, activation o f wound healing. Epithelial cells with highly reflective nuclei in this reg ion may be an indicator for an increased biologic stress caused by the devi ce. (C) 2000 by the American Academy of Ophthalmology.