Use of white light in vivo confocal microscopy for the detection of spatial changes in the corneal nerves in cases of early-stage Acanthamoeba keratitis with radial keratoneuritis.

Purpose Radial keratoneuritis (RK) is a common feature of Acanthamoeba keratitis (AK). In vivo confocal microscopy (IVCM) is noninvasive and provides real-time images for the diagnosis of corneal diseases by allowing the visualization of corneal structures and morphologies of living organisms at the cellular level. Images of AK with RK obtained using commercial white light IVCM devices have not been frequently evaluated. In the present study, a white light IVCM device was used to evaluate the corneal findings and describe spatial changes in the corneal nerves at different depths in cases of early-stage AK with RK. Methods In this retrospective, observational study, white light IVCM images focused on RK were evaluated for Acanthamoeba cysts/trophozoites, corneal deposits, and altered corneal nerves, with special emphasis on three-dimensional spatial changes in the corneal nerves at different depths. Results Seventeen eyes of 17 patients exhibiting early-stage AK with RK were included in the study. Acanthamoeba cysts/trophozoites were observed in the corneal epithelium of 13 eyes and stroma of 7 eyes. Alterations in the corneal nerve morphology and density were observed from the basal epithelial layer to the stromal layer in 12 eyes. Acanthamoeba trophozoites were attached to the corneal stromal nerves in five eyes. Conclusion These findings suggest that white light IVCM can identify consistent corneal findings, particularly spatial changes in the corneal nerves, in cases of early-stage AK with RK.