Purpose: To evaluate the relationship between the in vivo confocal microscopic (IVCM) morphology of subbasal corneal nerves, corneal sensitivity, and clinical parameters in patients with non-Sjögren dry eye disease (NSDD).

Methods: Forty-three patients with NSDD and 14 healthy age- and sex-matched control subjects were included. Each patient underwent an evaluation of ocular surface disease symptoms using the Ocular Surface Disease Index (OSDI); tear film break-up time (TBUT); corneal and conjunctival staining (Oxford scale); the Schirmer test; corneal sensation testing using the Cochet-Bonnet esthesiometer; and corneal subbasal nerve analysis with IVCM. One eye of each subject was included in the study.

Results: Mean corneal sensitivity was significantly lower in the NSDD group as compared with the control group (P = 0.014). Corneal subbasal nerves showed significant changes in NSDD patients as compared with normal subjects: lower density (P < 0.001); increased tortuosity (P < 0.001); number of beadings (P < 0.001); and width (P = 0.041). In patients with NSDD, corneal subbasal nerve density was correlated to age (r = -0.352, P = 0.021); the Oxford scale (r = -0.486, P = 0.01); and central corneal sensitivity (r = 0.383, P = 0.041). The maximum length of nerve fibers within a frame (MaxL) was correlated to the OSDI (r = -0.265, P = 0.019) and the Oxford scale (r = -0.307, P = 0.039). In multivariate analysis after adjustment for age, corneal subbasal nerve density remained correlated to the Oxford score (P < 0.001). The Oxford score was also correlated to central corneal sensitivity (r = -0.304, P = 0.042).

Conclusions: NSDD patients have both structural and functional alterations of subbasal corneal nerves and these changes are related to the severity of dry eye.