Discordant Dry Eye Disease (An American Ophthalmological Society Thesis).

PURPOSE: To improve understanding of dry eye disease and highlight a subgroup of patients who have a component of central sensitization and neuropathic pain contributing to their condition.
METHODS: Prospective, cross-sectional, IRB-approved study comparing isolated dry eye disease (n=48) to fibromyalgia (positive control; n=23) and healthy (negative control; n=26) individuals with ocular surface examination, corneal confocal microscopy, quantitative sensory testing, and self-reported ocular symptoms and systemic associations. A subset of patients also underwent skin biopsy and/or brain neuroimaging. Dry eye patients were split into concordant (ie, those with dry eyes on examination) and discordant (ie, those with dry eye symptoms but normal examination) subgroups for further analysis. We hypothesized that on the systemic measures included, concordant patients would resemble healthy controls, whereas discordant patients would show evidence of centralized mechanisms similar to fibromyalgia.
RESULTS: Schirmer test and Ocular Surface Disease Index (OSDI) scores indicated significant decreases in tear production (Schirmer: healthy, 18.5±8.2 mm; dry, 11.2±5.4 mm; fibromyalgia, 14.4±7.5; P<.001) and increases in self-reported dry eye symptoms (OSDI: healthy, 1.9±3.0; dry, 20.3±17.7; fibromyalgia, 20.3±17.1; P<.001) in the dry eye and fibromyalgia patients, compared to controls. The discordant subgroup had decreased corneal nerve density and decreased visual quality-of-life scores, similar to patients with fibromyalgia. Concordant patients were more similar to healthy controls on these measures.
CONCLUSIONS: Individuals with discordant dry eye may have a central pathophysiologic mechanism leading to their eye pain symptoms, which could be an important factor to consider in treatment of chronic idiopathic dry eye.