Dry Eye Exacerbation in Patients Exposed to Desiccating Stress under Controlled Environmental Conditions – Accepted Manuscript

Abstract: Purpose: To determine if controlled environmental conditions can induce acute exacerbations of signs and symptoms in dry eye and asymptomatic subjects.Design: Prospective cross-sectional study.Methods: Nineteen patients with dry eye and 20 asymptomatic controls were exposed to controlled low humidity (5% relative humidity, desiccating environment) for 2 hours in our Controlled Environmental Research Laboratory at the University of Valladolid. The patients completed the Single-Item Score Dry Eye Questionnaire and the following diagnostic tests were performed before and after exposure: tear osmolarity, phenol red thread test, conjunctival hyperemia, fluorescein tear-break-up time (T-BUT), Schirmer test, and ocular surface vital staining. Sixteen molecules in the tears samples were analyzed by multiplex bead analysis.Results: After exposure, the patients and controls had a significant (P≤0.003) increase in corneal staining (from 0.68±0.15 to 1.16±0.14 and 0.50±0.15 to 1.30±0.19, respectively), significantly decreased (P≤0.01) fluorescein T-BUT values (from 2.78±0.56 to 1.94±0.24 seconds and 2.81±0.24 to 2.13±0.19 seconds, respectively), and significantly increased (P≤0.03) matrix metallopeptidase-9 tear levels (from 10,054.4±7,326.6 to 25,744.5±13,212.4 and 10,620.5±4,494.3 to 16,398.7±5,538.3 pg/ml, respectively). In the control group, the epidermal growth factor tear levels decreased significantly (P=0.007) (from 1,872.1±340.7 to 1,107.1±173.6 pg/ml), and the interleukin-6 levels significantly (P<0.001) increased (from 29.6±5.8 to 54.3±8.3 pg/ml) after exposure.Conclusion: Adult patients with mild-to-moderate dry eye and asymptomatic subjects of similar ages can develop acute exacerbation in an environmental chamber that resembles the sudden worsening that patients with dry eye experience daily.