Abstract
Purpose :
It was observed that dry eye disease (DED) patients have morphological changes in the corneal nerve. The purpose of present study was to clarify the correlation between morphological changes of the corneal sub-basal nerve, subjective symptoms and ocular surface evaluation.
Methods :
Forty-three DED patients and 16 healthy subjects in Japan between the ages of 20-64 years old were selected on the basis of subjective symptoms (DEQ-5, OSDI, NOP, and VAS questionnaires) and on the basis of ophthalmological examinations (tear breakup time-TBUT; superficial punctate keratitis-SPK). Exclusion criteria consisted of the followings: having a combination of autoimmune diseases, Stevens-Johnson syndrome, a history of ophthalmic surgery, glaucoma, and ocular surface infectious disease. Additional exclusion criteria included use of eye drop medicine except for artificial tears and contact lenses. Corneal sub-basal nerves were observed using confocal laser scanning microscopy (HRT-3 with Rostock Cornea Module). Nerve lengths and densities were analyzed with ACCMetrix and CCMetrx as image analysis system to extract and quantify nerve fibers.
Results :
TBUT in DED [4.57 ± 1.99 sec (mean ± SD)] was significantly lower compared to healthy adults (8.40 ± 2.02 sec), and pain tolerance capacity in DED (44.1 ± 15.3 mm) was significantly lower than healthy adults (35.9 ± 11.4 mm). The number of branch points on the main fibers per 1 mm2 (Nerve Branch Density (CNBD)) in DED (21.3 ± 13.6) was significantly increased compared to healthy adults (14.6 ± 7.31). The total number of branch points per 1 mm2 (Nerve Fiber Total Branch Density (CTBD)) in DED (45.0 ± 28.3) was significantly increased compared to healthy subjects (28.6 ± 14.7). CNBD and CTBD were also positively correlated with TBUT, but not correlated with pain tolerance.
Conclusions :
The positive correlation between the TBUT (hallmark marker for DED) and the number of nerve branches suggested that morphological alterations in corneal nerves are also a characteristic of DED. These morphological alterations may be a cause or result of DED. A limitation of the present study was the relatively small number of patients.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.