In-vivo real-time tandem scanning confocal microscopic examination of wound healing in the cornea following an alkali burn

摘要

Abstract: Chemical burns of the cornea can cause irreversible scarring, leading to visual impairment. The tandem scanning confocal microscope (TSM) was used to evaluate stromal changes in vivo following exposure to alkali, the most devastating form of chemical ocular injury. The corneas of anesthetized rabbits were exposed to filter papers impregnated with NaOH. A 25x water immersion objective lens was used with the TSM, and images captured with a CCD camera. Normal keratocytes appeared as ovoid nuclei. Collagen lamellae were not visible. Alkali led to immediate opacification of the extracellular matrix and loss of keratocytes. The former was quantified by en-face serial optical sectioning and subsequent off-line densitometry of the captured image. Wound healing was monitored as spindle-shaped cells appeared at the wound edge. This was accompanied by the production of fibrillary extracellular matrix. After 3 days, branched cellular processes 100 to 200 $mu@m long were extended. By 1 week, dense aggregates of ovoid fibroblasts and whorls of collagen fibers had formed. Despite the overlying scarring, the deeper stromal layers and endothelium were still visible with this technique. We suggest that the TSM would be a useful clinical instrument for the evaluation and treatment evaluation of patients with chemical injuries of the cornea. !22