Corneal involvement in Crohn's disease: an in vivo confocal microscopy study

PURPOSE: To evaluate the corneal changes of patients with Crohn's disease (CD) using confocal microscopy and to investigate the association among confocal parameters and CD activity and CD treatment. METHODS: Thirty consecutive patients (age: 42 ± 12 years; 19 women and 11 men) affected by CD and 30 control eyes (age matched and gender matched) underwent an ophthalmic examination and, in 1 eye chosen at random, confocal microscopy of the central cornea using the cornea module of Heidelberg Retina Tomograph. The following confocal parameters were evaluated: density of basal epithelial cells, epithelial dendritic cells, anterior and posterior stromal keratocytes, and endothelial cells; the subbasal plexus was assessed for number and tortuosity of the nerve fibers. RESULTS: Routine ophthalmic evaluation was normal in the whole population. At confocal microscopy, 40% of patients with CD had hyperreflective dots in the basal epithelium, which were absent in the control group. Activation of keratocytes was found in 86.6% of patients with CD and was absent in the control group. Compared with controls, patients with CD had lower density of dendritic cells (12.2 ± 26.3 vs. 50.3 ± 37.6 cells per square millimeter; P = 0.001). The other confocal parameters were similar in the 2 groups. No correlation between CD activity index and confocal changes was found. CONCLUSION: Confocal microscopy can detect subtle corneal changes in patients with CD, which may be signs of subclinical inflammation.