Relation between corneal innervation with confocal microscopy and corneal sensitivity with noncontact esthesiometry in patients with dry eye

PURPOSE. An alteration in corneal innervation has been described in dry eye associated with diabetes mellitus, contact lens use, and LASIK. The purpose of this study was to evaluate whether dry eye not related to Sjogren's syndrome (NSDE) and dry eye related to primary Sjogren's syndrome (PSDE) are associated with an alteration of the corneal nerves and sensation. METHODS. Twenty-one patients with dry eye (10 NSDE and 11 PSDE) and 20 healthy volunteers were studied. Healthy volunteers were divided into two groups: one younger than 60 years (N < 60) and the other 60 years of age or older (N < 60). The study of the epithelium, stroma, and subbasal corneal nerves was performed with a confocal microscope. Mechanical, chemical, and thermal sensation was evaluated using the Belmonte noncontact esthesiometer. RESULTS. A statistically significant decrease in the number and density of subbasal nerves (P < 0.0001) and the density of superficial epithelial cells (P < 0.0001) was observed in dry eyes. The number and density of subbasal nerves was higher in the N < 60 group. A significant decrease was found with respect to mechanical, chemical, and thermal sensitivity (P < 0.0001). Sensibility was better in the healthy eyes. A strong correlation was found between the density of superficial epithelial cells and the nerves and between the number and density of subbasal nerves and sensation (P < 0.001). CONCLUSIONS. The use of confocal microscopy and noncontact esthesiometry allow the detection of the presence of corneal neuropathy in patients with dry eye.