Differential contributions of impaired corneal sensitivity and reduced tear secretion to corneal epithelial disorders.

BACKGROUND/AIMS: To determine the possible roles of impaired corneal sensitivity and reduced tear secretion in various types of corneal epithelial disorders. METHODS: A total of 99 patients (179 eyes) with corneal epithelial disorders classified as persistent epithelial defects (PED), corneal erosion, or superficial punctate keratopathy (SPK) and 115 individuals (230 eyes) without apparent ocular surface disorders (controls) were enrolled in a prospective study. Corneal sensitivity was measured with a Cochet-Bonnet esthesiometer, and tear secretion was measured by the Schirmer test in each subject. RESULTS: Corneal sensitivity of eyes in the PED and corneal erosion groups was significantly lower than that in the control group. Schirmer test values for eyes in the SPK group were significantly reduced compared with those in the control group. CONCLUSION: A loss of corneal sensitivity may contribute to the development of PED and corneal erosion, whereas reduced tear secretion may be a contributing factor for SPK. Both results indicate the importance of corneal sensory innervation to the maintenance of corneal integrity.