Dry eye symptom severity and persistence are associated with symptoms of neuropathic pain

Objective: Studies of patients with non-ocular pain suggest that it is therapeutically useful to identify those with features of neuropathic pain. No data is available, however, on whether this approach has similar utility in dry eye. The purpose of this study was to determine whether severity and persistence of dry eye symptoms associate with self-reported symptoms of neuropathic ocular pain (NOP). Methods Design: Cohort study. Participants/setting: 102 men seen in the Miami Veterans Affairs eye clinic. A baseline evaluation was performed consisting of the dry eye questionnaire 5 (DEQ5) and ocular surface evaluation. Patients were contacted ≥2 years later to repeat the DEQ5 and complete questionnaires that further characterised their eye pain. Main outcome measure: The relationship between dry eye symptom severity and persistence (DEQ5) and additional measures of ocular pain (NOP). Results: Of 102 patients with variable dry eye symptoms, 70 reported at least mild symptoms on both encounters (DEQ5≥6). Fifty-four of 70 (77%) reported ≥1 NOP feature, and the number of NOP features correlated moderately with dry eye symptoms at both encounters (r=0.31-0.46, p<0.01). Patients with any symptom of NOP had higher dry eye symptom scores at both encounters (p<0.05), but similar ocular surface parameters. Hypersensitivity to wind and photoallodynia were associated with having mild or greater symptoms on both encounters (OR 3.4, 95% CI 1.2 to 10.0, p=0.02; OR 15.6, 95% CI 2.0 to 123, p=0.009, respectively). Conclusions: NOP features are common in patients with symptomatic dry eye and these features correlate with symptom severity and persistence.