June 2013
Volume 54, Issue 15
Free
ARVO Annual Meeting Abstract  |   June 2013
Corneal Uptake of Oxygen In Vivo During Soft Contact Lens Wear
Author Affiliations & Notes
  • Percy Lazon De La Jara
    Brien Holden Vision Institute, Sydney, NSW, Australia
    School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia
  • Sho Takatori
    Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA
  • Klaus Ehrmann
    Brien Holden Vision Institute, Sydney, NSW, Australia
  • Arthur Ho
    Brien Holden Vision Institute, Sydney, NSW, Australia
    School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia
  • Brien Holden
    Brien Holden Vision Institute, Sydney, NSW, Australia
    School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia
  • Clayton Radke
    Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA
  • Footnotes
    Commercial Relationships Percy Lazon De La Jara, AMO (F), Allergan (F); Sho Takatori, None; Klaus Ehrmann, None; Arthur Ho, None; Brien Holden, Allergan (F), AMO (I); Clayton Radke, novartis corporation (F)
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 505. doi:
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      Percy Lazon De La Jara, Sho Takatori, Klaus Ehrmann, Arthur Ho, Brien Holden, Clayton Radke; Corneal Uptake of Oxygen In Vivo During Soft Contact Lens Wear. Invest. Ophthalmol. Vis. Sci. 2013;54(15):505.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract
 
Purpose
 

Critical oxygen need of the human cornea during soft contact lens (SCL) wear has received decades of attention with polarograpy the primary in-vivo experiment. Unfortunately, classical analysis of the polarographic oxygen sensor (POS) misinterprets electrode behavior. We develop a new method to assess in-situ corneal oxygen uptake during SCL wear using a micro-polarographic Clark electrode.

 
Methods
 

After steady SCL wear and subsequent lens removal, a membrane-covered POS is immediately placed onto the cornea and transient oxygen tension recorded. A semi-logarithmic graph of oxygen tension versus time at long time is created to give corneal oxygen uptake, Jo(0). We apply our procedure to polarographic data for ten human subjects with 12 different commercial SCL during open eye.

 
Results
 

The average corneal oxygen uptake rates for ten subjects with 12 different commercial SCLs vary from 2 - 10 μL(STP)/cm2 /h at open eye. In Fig. 1, filled circles give oxygen uptake into the cornea with lens wear, Jo(0), relative to that without lens wear, Jo*(0), as a function of SCL transmissibility. The solid line corresponds to a theoretical model, which corroborates well with the experimental data. Lenses with oxygen transmissibilities around Dk/t ~ 150 hBarrer/cm have uptake rates of ~ 10 μL(STP)/cm2/h, in close agreement with our previously obtained no-lens human uptake rates of 9 - 13 μL(STP)/cm2/h at open eye (Takatori et al. IOVS. 2012; 53: 6331-6337).

 
Conclusions
 

Application of the classical procedure to our experimental data gives corneal-uptake results that are about three to five times smaller those classically reported. According to our corrected procedure, full oxygenation of the human eye, 11.3 μL/cm2 /h for the 10 subjects studied, is reached only asymptotically (see Fig. 1). That is, very high lens transmissibility is required before the lens no longer impedes oxygen transport. Conversely, 95 % anterior corneal oxygenation is achieved with a lens transmissibility of 150 hBarrer/cm.

 
 
Fig 1. Reduction of oxygen uptake into the human cornea by SCL wear at open eye, as a function of lens transmissibility.
 
Fig 1. Reduction of oxygen uptake into the human cornea by SCL wear at open eye, as a function of lens transmissibility.
 
Keywords: 477 contact lens • 635 oxygen  
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