In vitro interferometric characterization of dynamic fluid layers on contact lenses

Brian C. Primeau, John E. Greivenkamp, John J. Sullivan

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

3 Scopus citations


The anterior refracting surface of the eye when wearing a contact lens is the thin fluid layer that forms on the surface of the contact lens. Under normal conditions, this fluid layer is less than 10 microns thick. The fluid layer thickness and topography change over time and are affected by the material properties of the contact lens, and may affect vision quality and comfort. An in vitro method of characterizing dynamic fluid layers applied to contact lenses mounted on mechanical substrates has been developed using a phase-shifting Twyman-Green interferometer. This interferometer continuously measures light reflected from the surface of the fluid layer, allowing precision analysis of the dynamic fluid layer. Movies showing this fluid layer behavior can be generated. The fluid behavior on the contact lens surface is measured, allowing quantitative analysis beyond what typical contact angle or visual inspection methods provide. The interferometer system has measured the formation and break up of fluid layers. Different fluid and contact lens material combinations have been used, and significant fluid layer properties have been observed in some cases. The interferometer is capable of identifying features in the fluid layer less than a micron in depth with a spatial resolution of about ten microns. An area on the contact lens approximately 6 mm wide can be measured with the system. This paper will discuss the interferometer design and analysis methods used. Measurement results of different material and fluid combinations are presented.

Original languageEnglish (US)
Title of host publicationDimensional Optical Metrology and Inspection for Practical Applications
StatePublished - 2011
EventDimensional Optical Metrology and Inspection for Practical Applications - San Diego, CA, United States
Duration: Aug 22 2011Aug 23 2011

Publication series

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


OtherDimensional Optical Metrology and Inspection for Practical Applications
Country/TerritoryUnited States
CitySan Diego, CA


  • Contact lens
  • 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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