title: A novel, dynamic, in vivo, non-contact method of measuring oxygen depletion rate of the anterior eye.
abstract: OBJECTIVE
  Despite the importance of oxygen measurements, techniques have been limited by their invasive nature and small corneal area of assessment. The aim of this study was to assess a non-contact way of measuring oxygen uptake of the whole anterior eye.
  
  
  METHODS
  The device consisted of a goggle with an oxygen sensitive material on the inner surface. As the output is affected by temperature, a second probe was inserted into the goggle to compensate. The goggle was positioned over the eye on 10 subjects (mean age 30.5±5.0 years, 3:2 male:female) to assess the oxygen depletion of the unrestricted, blinking eye. Measurements were taken over a 3 min period. The volume contained within the goggle and bone structure of individual eyes was measured by water volume displacement and the output corrected to O(2)% reduction/cm(3) over a 30s period. To check the discriminatory ability of the device, measurements were taken in open-eye and closed-eye conditions, along with on the subjects' skin (cheek) for comparisons.
  
  
  RESULTS
  The oxygen depletion measure over 30s was on average 3.10±1.51 O(2)%cm(3) during open eye condition, significantly more than during closed eye conditions (1.26±1.52 O(2)%cm(3)). The skin (control) showed a negligible oxygen uptake (0.19±0.33 O(2)%cm(3)). The results demonstrated good repeatability with a mean standard deviation of around 0.4 O(2)%cm(3) (equating to 11%).
  
  
  CONCLUSIONS
  The technique demonstrated a non-invasive, non-contact method of measuring consumption of oxygen within the goggle (oxygen depletion rate) and showed good within-visit repeatability.
authors.affiliation: Ophthalmic Research Group, School of Life Sciences, Aston University, Birmingham B4 7ET, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Cardall
authors.forename: Shehzad A
authors.initials: SA
authors.lastname: Naroo
authors.forename: James S
authors.initials: JS
authors.lastname: Wolffsohn
mesh_terms: D000328:Adult; D003261:Contact Lenses; D003315:Cornea / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009885:Ophthalmology / Q000295:instrumentation; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*
chemical_list: D010100:Oxygen