Two-year corneal endothelial cell assessment following INTACS implantation

PURPOSE: To evaluate the 2-year effects of intrastromal corneal ring segmen ts (INTACS) on the corneal endothelium. METHODS: Non-contact specular microscopy was performed as a subgroup. test in a Phase III clinical trial. Endothelial cell images were collected befor e surgery and at 6, 12, and 24 months after surgery at the central and peri pheral (6 and 10 o'clock) regions. Images were recorded and analyzed later by a central reading center. Cell density, coefficient of variation, and pe rcent hexagonal cells were determined. RESULTS: There were no clinically significant changes in the endothelial ce ll structure at 6, 12, and 24 months (102 eyes). There was a gain of 5 cell s/mm(2) (6 months) and 3 cells/mm(2) (12 months) at the central region of t he cornea and a loss of 28 cells/mm(2) at 24 months. At the 6 o'clock regio n of the cornea, there was a loss of 0, 24, and 92 cells/mm(2) at 6, 12, an d 24 months. At the 10 o'clock region of the cornea, there was a loss of 14 , 30, and 94 cells/mm(2) at 6, 12, and 24 months. INTACS did not statistica lly affect the central cell density at 6 and 12 months, however, there was a slight loss centrally at 24 months. At 24 months, all corneal regions had a slight decrease in cell density, In all eyes, mean central and periphera l endothelial cell counts remained above 2495 cells/mm(2). Coefficient of v ariation improved and percent hexagonal cells remained unchanged. CONCLUSION: Endothelial cell density changes at 2 years after INTACS implan tation were not clinically significant and endothelial cell remodeling was present.