Abstract
Purpose::
To correlate corneal nerve morphology changes by in vivo confocal microscopy with esthesiometry results in patients with herpes zoster ophthalmicus (HZO).
Methods::
In a prospective study, we used a Cochet-Bonnet esthesiometer (Luneau Ophthalmologia) and a CS4 confocal microscope (Nidek Technologies) in both the affected and contralateral eyes of 10 patients with herpes zoster keratitis, as well as in 10 normal eyes of 5 subjects. Corneal sensation and confocal images of the subbasal nerve plexus were obtained centrally. Two masked observers reviewed the confocal images in regards to corneal nerve morphology, including the total number of nerves, number of main nerve trunks, total length of nerves per image, nerve interconnections, branching pattern, and tortuosity. Based on corneal sensation, eyes of HZO patients were stratified into normal (corneal sensation >5.5 cm), mild (corneal sensation >2.5 cm and ≤5.5 cm), and severe (corneal sensation≤2.5 cm) groups.
Results::
Total nerve count and total nerve length in HZO eyes were significantly lower than normal eyes (p<0.001). In HZO subgroups, total nerve count as well as total nerve length correlated strongly with corneal sensation (p<0.005). However, other corneal nerve characteristics, including branching, interconnection, and tortuosity did not show a significant correlation with the severity of loss of corneal sensation.
Conclusions::
The significant decrease in total number of subbasal nerve fibers, as well as total nerve length in HZO eyes strongly correlates with the decrease in corneal sensation. In vivo confocal microscopy reveales HZO-induced alterations of subbasal nerve morphology and thus enables a direct comparison of corneal sensory innervation and sensitivity.
Keywords: microscopy: confocal/tunneling • varicella zoster virus • innervation: sensation