Morphological changes of corneal subepithelial nerve plexus in different types of herpetic keratitis.

PURPOSE: We investigated by in vivo confocal microscopy alterations in the subepithelial nerve plexus in different types of herpes simplex keratitis (HSK).

METHODS

Seventeen patients (seven women and ten men, mean age 63.9 years) with a history of HSK were classified into three groups according to the classification of Herpetic Keratitis Infection Research Group. Slit-lamp examinations, corneal sensitivity measurements, and corneal in vivo confocal microscopy examinations [Rostock Corneal Module attached to the Heidelberg Retina Tomograph II (HRT II-RCM)] were performed.

RESULTS

Among the 17 cases, three were classified as epithelial type, ten as stromal type, and four as endothelial type HSK. The average corneal sensitivities were 11.41 ± 9.46 mm in the affected eyes and 43.24 ± 12.2 mm in controls. Decreases in three parameters in the affected eyes (long nerve-fiber density, nerve-branch density, nerve thickness) were statistically significant compared with controls. Decreases in the three parameters were more remarkable in the epithelial and stromal types than in the endothelial type.

CONCLUSION

The morphology of the corneal subepithelial nerve plexus may get gradually destroyed along with recurrent episodes of epithelial and stromal HSK. However, the destruction does not seem remarkable in the endothelial type of HSK, suggesting the possibility of a different route of virus recruitment in this type.