Dynamic measurement of the corneal tear film with a twyman-green interferometer

Jason D. Micali, John E. Greivenkamp, Brian C. Primeau

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


An interferometer for measuring dynamic properties of the in vivo tear film on the human cornea has been developed. The system is a near-infrared instantaneous phase-shifting Twyman-Green interferometer. The laser source is a 785 nm solidstate laser; the system has been carefully designed and calibrated to ensure that the system operates at eye safe levels. Measurements are made over a 6 mm diameter on the cornea. Successive frames of interferometric height measurements are combined to produce movies showing both the quantitative and qualitative changes in the topography of the tear film surface and structure. To date, measurement periods of up to 120 seconds at 28.6 frames per second have been obtained. Several human subjects have been examined using this system, demonstrating a surface height resolution of 25 nm and spatial resolution of 6 μm. Examples of features that have been observed in these in preliminary studies of the tear film include: post-blink disruption, evolution, and stabilization of the tear film; tear film artifacts generated by blinking; tear film evaporation and break-up; and the propagation of foreign objects in the tear film. This paper discusses the interferometer design and presents results from in vivo measurements.

Original languageEnglish (US)
Title of host publicationInterferometry XVII
Subtitle of host publicationAdvanced Applications
EditorsErik L. Novak, Christophe Gorecki, Peter J. de Groot, Cosme Furlong
ISBN (Electronic)9781628412314
StatePublished - 2014
EventInterferometry XVII: Advanced Applications - San Diego, United States
Duration: Aug 18 2014Aug 20 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherInterferometry XVII: Advanced Applications
Country/TerritoryUnited States
CitySan Diego


  • Contact lens
  • Corneal topography
  • Fluid layer
  • Interferometry
  • Tear film

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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