Purpose:
To study the early changes of ocular surface in patients with chemical injury by using in vivo laser scanning confocal microscopy (LSCM).
Methods:
Eleven eyes injured by chemicals (2 eye acid, 9 eyes alkali) were enrolled in this study. According to the Roper Hall classification, 3 eyes were Class I, 2 eyes Class II, 4 eyes Class III, and 2 eyes Class IV. The changes of cornea, limbus and bulbar conjunctiva of enrolled eyes were evaluated by LSCM at 1, 2 and 3 months after injury. The densities of infiltrated inflammatory cells (ICs) and Langerhans cells (LCs) were quantified and analyzed.
Results:
Eyes classified as Class I were characterized by the recovery of corneal epithelial morphology 2 months after injury and unaffected Vogt palisades. In eyes classified as Class II, corneal basal epithelial cells with hyperreflective nuclei couldn’t be found until 2 months after injury. Blood vessels at the limbus were distinctively dilated with massive LCs infiltration. As for eyes of Class III, LSCM showed that one month after injury, corneal epithelial cells metaplasized with bright cytoplasm, leading to corneal conjunctivalization 3 months later. For those with the most severe injury, loss of corneal epithelium and generalized activation of keratocytes were identified. Rarely can the recovery of such changes be observed at 3 months after injury. In eyes of Class III and IV, it was found in the substantia propria of conjunctiva that the fibers were extremely distorted and partial blood vessels near limbus obstructed. The typical Vogt palisades disappeared, leaving fiberized limbal stroma. Corneal neovascularization developed 2 months after injury. At each examination time point, the infiltrations of numerous ICs in the limbus and conjunctiva were visible.
Conclusions:
Our findings support the use of LSCM as a valid technique for the study of the early changes of ocular surface in patients with chemical injury.
Keywords: cornea: clinical science • imaging/image analysis: clinical • microscopy: confocal/tunneling