April 2009
Volume 50, Issue 13
ARVO Annual Meeting Abstract  |   April 2009
Diffusion of Oxygen is Slower in Vitreous Gel Than in Saline in Agreement With the Stokes Einstein Equation
Author Affiliations & Notes
  • S. Gisladottir
    Department of Ophthalmology,
    University of Iceland, Reykjavik, Iceland
  • T. Loftsson
    Department of Pharmacy,
    University of Iceland, Reykjavik, Iceland
  • E. Stefansson
    Department of Ophthalmology,
    University of Iceland, Reykjavik, Iceland
    Ophthalmology, National University Hospital, Reykjavik, Iceland
  • Footnotes
    Commercial Relationships  S. Gisladottir, None; T. Loftsson, None; E. Stefansson, None.
  • Footnotes
    Support  Doktorsstyrkur Rannsóknarsjóðs HÍ; Univ. Iceland Research Fund and Helga Jónsdóttir and Sigurliði Kristjánsson Memorial Fund.
Investigative Ophthalmology & Visual Science April 2009, Vol.50, 78. doi:
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      S. Gisladottir, T. Loftsson, E. Stefansson; Diffusion of Oxygen is Slower in Vitreous Gel Than in Saline in Agreement With the Stokes Einstein Equation. Invest. Ophthalmol. Vis. Sci. 2009;50(13):78.

      Download citation file:

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

  • Supplements

Purpose: : The laws of Stokes-Einstein and Fick postulate that the rate of diffusion is inversely related to the viscosity of the medium. The viscosity of vitreous gel is greater than water. In vitrectomy the vitreous gel is removed and replaced with saline and the diffusion coefficient and the rate of transport by diffusion within the vitreous cavity is increased. We test this hypothesis in vitro using O2 as the signal molecule.

Methods: : Specially designed diffusion cells were used (PermeGear, Inc, Hellertown, PA, USA) with a middle chamber filled with either saline solution or porcine vitreous humour, separated by cellophane membranes (MWCO 12,000-14,000). The decreasing pO2 was measured in a lower chamber as oxygen diffused through vitreous humour or saline solution to an upper chamber, where pure N2 bubbled. A double layer of cellophane membranes was used as a reference, with no middle chamber. An oxygen sensor, OxyLab pO2 (Oxford Optronix Ltd., Oxford, UK) was used to measure the concentration of oxygen under standardized conditions. The diffusion coefficient of the vitreous gel and saline solution were calculated, using Fick’s law. The resistance of the membranes was subtracted in order to find the diffusion coefficient for the vitreous gel or saline solution only.

Results: : The average pO2 in the lower chamber decreased over 2 hours from 149.2±3.3 mmHg to 138.6±6.0 mmHg (n=8) with vitreous gel in the middle chamber. With saline solution in the middle chamber the pO2 dropped from 146.1±3.4 mmHg to 136.8±2.7 mmHg in 1 hour (n=8). The double membrane reference showed a decrease in pO2 from 145.2±5.8 mmHg to 136.3±5.2 mmHg in 30 minutes (n=9). The diffusion coefficient for the vitreous gel was calculated as 0.0045±0.0016 mmHg/hour*cm2 (n=8) and for the saline solution 0.020 ± 0.0055 mmHg/hour*cm2 (n=8, p=0.000, Student's t-test). According to this, oxygen diffuses about 4 times faster through physiological saline solution than vitreous gel.

Keywords: vitreous • vitreoretinal surgery • vitreous substitutes 

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.