title: Influence of a controlled environment simulating an in-flight airplane cabin on dry eye disease.
abstract: OBJECTIVE
  To evaluate symptoms, signs, and the levels of 16 tears inflammatory mediators of dry eye (DE) patients exposed to an environment simulating an in-flight air cabin in an environmental chamber.
  
  
  METHODS
  Twenty DE patients were exposed to controlled environment simulating an in-flight airplane cabin (simulated in-flight condition [SIC]) of 23°C, 5% relative humidity, localized air flow, and 750 millibars (mb) of barometric pressure. As controls, 15 DE patients were subjected to a simulated standard condition (SSC) of 23°C, 45% relative humidity, and 930 mb. A DE symptoms questionnaire, diagnostic tests, and determination of 16 tear molecules by multiplex bead array were performed before and 2 hours after exposure.
  
  
  RESULTS
  After SIC exposure, DE patients became more symptomatic, suffered a significant (P ≤ 0.05) decrease in tear stability (tear break up time) (from 2.18 ± 0.28 to 1.53 ± 0.20), and tear volume (phenol red thread test), and a significant (P ≤ 0.05) increase in corneal staining, both globally (0.50 ± 0.14 before and 1.25 ± 0.19 after) and in each area (Baylor scale). After SSC, DE patients only showed a mild, but significant (P ≤ 0.05), increase in central and inferior corneal staining. Consistently, tear levels of IL-6 and matrix metalloproteinase (MMP)-9 significantly increased and tear epidermal growth factor (EGF) significantly decreased (P ≤ 0.05) only after SIC.
  
  
  CONCLUSIONS
  The controlled adverse environment conditions in this environmental chamber can simulate the conditions in which DE patients might be exposed during flight. As this clearly impaired their lacrimal functional unit, it would be advisable that DE patients use therapeutic strategies capable of ameliorating these adverse episodes.
authors: Institute for Applied OphthalmoBiology (IOBA), University of Valladolid, Valladolid, Spain.
authors: Marisa
authors: M
authors: Tesón
authors: María J
authors: MJ
authors: González-García
authors: Alberto
authors: A
authors: López-Miguel
authors: Amalia
authors: A
authors: Enríquez-de-Salamanca
authors: Vicente
authors: V
authors: Martín-Montañez
authors: María Jesús
authors: MJ
authors: Benito
authors: María Eugenia
authors: ME
authors: Mateo
authors: Michael E
authors: ME
authors: Stern
authors: Margarita
authors: M
authors: Calonge
mesh_terms: D000368:Aged; D000401:Aircraft; D001273:Atmosphere Exposure Chambers; D003315:Cornea / Q000473:pathology; D015352:Dry Eye Syndromes / Q000209:etiology* / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D004780:Environment, Controlled; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006813:Humidity; D008297:Male; D008875:Middle Aged; D013666:Tears / Q000378:metabolism