title: Factors predicting the ocular surface response to desiccating environmental stress.
abstract: OBJECTIVE
  To identify factors predicting the ocular surface response to experimental desiccating stress.
  
  
  METHODS
  The ocular surfaces of both eyes of 15 normal and 10 dry eye subjects wearing goggles were exposed to a controlled desiccating environment (15%-25% relative humidity and 2-5 L/min airflow) for 90 minutes. Eye irritation symptoms, blink rate, tear meniscus dimensions, noninvasive (RBUT) and invasive tear break-up time, and corneal fluorescein and conjunctival lissamine green-dye staining were recorded before and after desiccating stress. Pre- and postexposure measurements were compared, and Pearson correlations between clinical parameters before and after desiccating stress were calculated.
  
  
  RESULTS
  Corneal and conjunctival dye staining significantly increased in all subjects following 90-minute exposure to desiccating environment, and the magnitude of change was similar in normal and dry eye subjects; except superior cornea staining was greater in dry eye. Irritation severity in the desiccating environment was associated with baseline dye staining, baseline tear meniscus height, and blink rate after 45 minutes. Desiccation-induced change in corneal fluorescein staining was inversely correlated to baseline tear meniscus width, whereas change in total ocular surface dye staining was inversely correlated to baseline dye staining, RBUT, and tear meniscus height and width. Blink rate from 30 to 90 minutes in desiccating environment was higher in the dry eye than normal group. Blink rate significantly correlated to baseline corneal fluorescein staining and environmental-induced change in corneal fluorescein staining.
  
  
  CONCLUSIONS
  Ocular surface dye staining increases in response to desiccating stress. Baseline ocular surface dye staining, tear meniscus height, and blink rate predict severity of ocular surface dye staining following exposure to a desiccating environment.
authors.affiliation: George R. Brown School of Engineering, Rice University, Houston, TX, USA.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Alex
authors.forename: Austin
authors.initials: A
authors.lastname: Edwards
authors.forename: J Daniel
authors.initials: JD
authors.lastname: Hays
authors.forename: Michelle
authors.initials: M
authors.lastname: Kerkstra
authors.forename: Amanda
authors.initials: A
authors.lastname: Shih
authors.forename: Cintia S
authors.initials: CS
authors.lastname: de Paiva
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Pflugfelder
mesh_terms: D000328:Adult; D001767:Blinking / Q000502:physiology; D003228:Conjunctiva / Q000378:metabolism*; D003315:Cornea / Q000378:metabolism*; D003890:Desiccation; D015352:Dry Eye Syndromes / Q000378:metabolism*; D005135:Eye Protective Devices; D005260:Female; D019793:Fluorescein / Q000378:metabolism; D006801:Humans; D008086:Lissamine Green Dyes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D013194:Staining and Labeling; D013312:Stress, Physiological; D011795:Surveys and Questionnaires; D013666:Tears / Q000502:physiology
chemical_list: D008086:Lissamine Green Dyes; D019793:Fluorescein
keywords: cornea; dry eye; tears