Confocal Microscopic Characterization of Initial Corneal Changes of Surfactant-Induced Eye Irritation in the Rabbit

Use of In Vivo Confocal Microscopy to Understand the Pathology of Accidental Ocular Irritation

“…In vivo CM has been specifically used as a research tool for quantitative, in situ measurement of corneal wound contraction, fibroblast migration, corneal endothelial cell migration, corneal epithelial cell size and desquamation following contact lens wear and surgery, and the assessment of corneal surface toxicity following application of commonly used ophthalmic preservatives (22,23). Compared to other microscopes used to examine the cornea, the in vivo CM provides perspective regarding the cellular nature of the cornea unlike the slit-lamp microscope (7) and allows all layers of the cornea to be assessed unlike the specular microscope with which only the surface epithelium and endothelium can be observed (2,7,22,23 (12,13,17). For (12,13,17).…”

“…Compared to other microscopes used to examine the cornea, the in vivo CM provides perspective regarding the cellular nature of the cornea unlike the slit-lamp microscope (7) and allows all layers of the cornea to be assessed unlike the specular microscope with which only the surface epithelium and endothelium can be observed (2,7,22,23 (12,13,17). For (12,13,17). Consistent with the loss of superficial epithelium, we quantitatively showed that the epithelial layer was attenuated (12,13,17).…”

“…The general approach taken has been to correlate in vitro test results to scores derived from macroscopic examination of rabbit eyes in either the Draize test or LVET (19). This lack of success can be attributed to the fact that the current in vivo scoring system provides very descriptive and subjective information (13,17,19 (12,13,(17)(18)(19). And second, changes in types and/or levels of biomarkers, cytokines or extracellular factors, will reflect differences in the extent of initial damage (i.e., area and depth of injury) ; the initial responses (e.g., edema, neutrophilic infiltrate) ; and the eventual repair processes (e.g., neovascularization, epithelial regeneration, collagen deposition) (17)(18)(19).…”

“…This lack of success can be attributed to the fact that the current in vivo scoring system provides very descriptive and subjective information (13,17,19 (12,13,(17)(18)(19). And second, changes in types and/or levels of biomarkers, cytokines or extracellular factors, will reflect differences in the extent of initial damage (i.e., area and depth of injury) ; the initial responses (e.g., edema, neutrophilic infiltrate) ; and the eventual repair processes (e.g., neovascularization, epithelial regeneration, collagen deposition) (17)(18)(19). Further, these biomarkers can be applied to in vitro systems as predictors of eye irritation (17)(18)(19) (12,13,17).…”

“…And second, changes in types and/or levels of biomarkers, cytokines or extracellular factors, will reflect differences in the extent of initial damage (i.e., area and depth of injury) ; the initial responses (e.g., edema, neutrophilic infiltrate) ; and the eventual repair processes (e.g., neovascularization, epithelial regeneration, collagen deposition) (17)(18)(19). Further, these biomarkers can be applied to in vitro systems as predictors of eye irritation (17)(18)(19) (12,13,17). Additionally, this approach allows us to conserve animal use (13).…”