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

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.

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.

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.

Confocal microscopy can detect subtle corneal changes in patients with CD, which may be signs of subclinical inflammation.