Abstract
Purpose: :
The objective of this study was to determine whether dry eye is associated with alterations in corneal innervation and sensitivity.
Methods: :
20 healthy volunteers (10 younger than 60 years and 10 60 years or more) and 21 patients with dry eye (10 with non–Sjögren dry eye and 11 with Sjögren–related dry eye) were examined by confocal microscopy (Confoscan model P4, Tomey AG, Erlangen–Tennenlohe, Germany) and non–contact Belmonte's esthesiometry.
Results: :
As regards the number and density of subbasal nerves, a statistically significant difference (p<0.001) was found between healthy subjects and patients with dry eye. A statistically significant difference was also found between the 2 groups with respect to the density of the superficial epithelial cells (p<0.001) and anterior stromal cells (p<0.05). The mechanical, chemical and thermal corneal sensitivity was found to be significantly different between healthy subjects and patients with dry eye (p<0.001). It was observed that the dry eyes with a lower corneal sensitivity had a lower number of subbasal nerves. Moreover, we found that corneal sensitivity correlates with certain clinical parameters such as Schirmer's testing and rose bengal staining (p<0.01).
Conclusions: :
The use of confocal microscopy and esthesiometry allow the detection of the presence of corneal neuropathy in patients with dry eye. The demonstration of such alteration in corneal innervation in patients with dry eye opens the way for possible new lines of treatment for this disease.
Keywords: cornea: tears/tear film/dry eye • cornea: epithelium • cornea: stroma and keratocytes