Confocal microscopy of the corneas of long-term rigid contact lens wearers

Slit scanning confocal microscopy (Tomey Confoscan P4) was used to evaluate the central cornea of 22 subjects who had been wearing rigid lenses on a long-term, daily wear basis. Anterior and posterior keratocyte densities appeared unaffected by rigid lens wear (P = 0.10 and 0.34 for anterior and posterior keratocyte densities, respectively). Subjects with a previous history of polymethyl methacrylate (PMMA) lens wear showed a reduction in anterior keratocyte density (AKD) (P < 0.0001) and an increased level of haze in the anterior stroma. This may represent previous hypoxic damage. Endothelial cell density (ECD) was unaffected by rigid lens wear (P = 0.36) although an increase in endothelial polymegethism was evident (P < 0.0001). Subjects who had only worn rigid lenses with no history of PMMA lens wear did not show an increase in endothelial polymegethism (P = 0.10). An increased number of microdot opacities compared to the non-lens wearing eye was apparent (P = 0.05). The number of microdot opacities induced by rigid lenses, as reported in this study, appears to be less than that reported by others in respect of soft lenses.