Persistent Link:
http://hdl.handle.net/10150/202971
Title:
INTERFEROMETRIC CHARACTERIZATION OF TEAR FILM DYNAMICS
Author:
Primeau, Brian Christopher
Issue Date:
2011
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. When a contact lens is on worn, the tear film covers the contact lens as it would a bare cornea, and is affected by the contact lens material properties. Tear film irregularity can cause both discomfort and vision quality degradation. Under normal conditions, the tear film is less than 10 microns thick and the thickness and topography change in the time between blinks. In order to both better understand the tear film, and to characterize how contact lenses affect tear film behavior, two interferometers were designed and built to separately measure tear film behavior in vitro and in vivo. 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 in vivo interferometer is a similar system, with additional modules included to provide capability for human testing. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or videokeratometry and provides better sensitivity and resolution than shearing interferometry methods. The in vitro 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. This dissertation discusses the design of this interferometer along with analysis methods used. Example measurement results of different contact lens are presented highlighting the capabilities of the instrument. This dissertation also provides the in vivo interferometer design, along with the considerations that must be taken when designing an interferometer for on-eye diagnostics. Discussions include accommodating eye movement, design of null optics for a range of ocular geometries, and laser emission limits for on-eye interferometry in general.
Type:
text; Electronic Dissertation
Keywords:
Interferometry; Metrology; Optical systems; Tear film; Optical Sciences; Contact Lens; Corneal topography
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Optical Sciences
Degree Grantor:
University of Arizona
Advisor:
Greivenkamp, John E.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleINTERFEROMETRIC CHARACTERIZATION OF TEAR FILM DYNAMICSen_US
dc.creatorPrimeau, Brian Christopheren_US
dc.contributor.authorPrimeau, Brian Christopheren_US
dc.date.issued2011-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. When a contact lens is on worn, the tear film covers the contact lens as it would a bare cornea, and is affected by the contact lens material properties. Tear film irregularity can cause both discomfort and vision quality degradation. Under normal conditions, the tear film is less than 10 microns thick and the thickness and topography change in the time between blinks. In order to both better understand the tear film, and to characterize how contact lenses affect tear film behavior, two interferometers were designed and built to separately measure tear film behavior in vitro and in vivo. 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 in vivo interferometer is a similar system, with additional modules included to provide capability for human testing. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or videokeratometry and provides better sensitivity and resolution than shearing interferometry methods. The in vitro 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. This dissertation discusses the design of this interferometer along with analysis methods used. Example measurement results of different contact lens are presented highlighting the capabilities of the instrument. This dissertation also provides the in vivo interferometer design, along with the considerations that must be taken when designing an interferometer for on-eye diagnostics. Discussions include accommodating eye movement, design of null optics for a range of ocular geometries, and laser emission limits for on-eye interferometry in general.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectInterferometryen_US
dc.subjectMetrologyen_US
dc.subjectOptical systemsen_US
dc.subjectTear filmen_US
dc.subjectOptical Sciencesen_US
dc.subjectContact Lensen_US
dc.subjectCorneal topographyen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineOptical Sciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorGreivenkamp, John E.en_US
dc.contributor.committeememberSchwiegerling, Jamesen_US
dc.contributor.committeememberLiang, Rongguangen_US
dc.contributor.committeememberGreivenkamp, John E.en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.