March 2012
Volume 53, Issue 14
Free
ARVO Annual Meeting Abstract  |   March 2012
What Influences The Shear Rate Acting On Silicone Oil To Cause It To Emulsify?
Author Affiliations & Notes
  • Yau Kei J. Chan
    Eye Institute, LKS Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong
  • Theodor Stappler
    St Paul's Eye Unit, Royal Liverpool Univ Hospital, Liverpool, United Kingdom
  • David Wong
    Eye Institute, LKS Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong
  • Footnotes
    Commercial Relationships  Yau Kei J. Chan, None; Theodor Stappler, None; David Wong, None
  • Footnotes
    Support  University Development Fund in University of Hong Kong and the K.B. Woo Foundation
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 3770. doi:
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    • Get Citation

      Yau Kei J. Chan, Theodor Stappler, David Wong; What Influences The Shear Rate Acting On Silicone Oil To Cause It To Emulsify?. Invest. Ophthalmol. Vis. Sci. 2012;53(14):3770.

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

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Abstract

Purpose: : Emulsification of silicone oil is caused by the shear force generated by eye movement. In the past, we investigated the effect of shear- and extensional-viscosities of silicone oil on the shear rate. We now study the extent of silicone oil filling and the presence of indentation within the vitreous cavity.

Methods: : A model eye chamber made of surface-modified polymethymethacrylate (capacity 6ml) was driven by a stepper-motor to mimic large-amplitude eye movements (amplitude 90o, angular velocity 360o/s and a duration 300ms). Two indents made of agarose were introduced to simulate an encircling scleral buckling. Two silicone oils (1,300 and 5,000mPa.s), three volumes (3, 4 and 5ml) and two eye chambers (with and without indents) were tested. The movements of the oils inside the model chamber were captured by video recordings.

Results: : The presence of indentation significantly reduced the velocity of the oil relative to the eye chamber. The extent of fill and the viscosity also had a significant but lesser effect. The peak velocity of the oil relative to the eye chamber was recorded at 349o/s. This occurred when there was no indentation in the chamber and when it was filled with 3 ml of 1,300mPa.s oil.

Conclusions: : Of the three factors investigated, the presence of indent seemed to have the greatest influence on the shear rate. Scleral buckling and a more complete fill of an eye cavity may be as important as the use of high viscosity oils in preventing emulsification.

Keywords: vitreous substitutes • vitreoretinal surgery • eye movements 
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