Fast absolute-reflectance method for the determination of tear film lipid layer thickness
AssigneeJohnson & Johnson Surgical Vision, Inc.
InventorsStan Huth, Denise Tran
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Abstract
A method of determining tear film lipid layer thickness. The method includes the steps of measuring a tear film aqueous plus lipid layer relative reflectance spectrum using a wavelength-dependent optical interferometer; converting the measured tear film aqueous plus lipid layer relative reflectance spectrum to a calculated absolute reflectance spectrum; and comparing the calculated absolute reflectance spectrum to a theoretical absolute lipid reflectance spectrum to determine a tear film lipid layer thickness.
Claims22
A method of determining tear film lipid layer thickness, comprising the steps of:
- measuring a tear film aqueous plus lipid layer relative reflectance spectrum using a wavelength-dependent optical interferometer;
- converting the measured tear film aqueous plus lipid layer relative reflectance spectrum to a calculated absolute reflectance lipid spectrum, wherein the calculated absolute reflectance lipid spectrum is calculated based on wavelength-dependent refractive indices for air, lipid, and aqueous phases and wherein the wavelength-dependent refractive indices for lipid are based upon a Sellmeier equation form;
- and
- comparing the calculated absolute reflectance lipid spectrum to a theoretical absolute reflectance lipid spectrum to determine a tear film lipid layer thickness.
A system for determining tear film lipid layer thickness, comprising:
- a wavelength-dependent optical interferometer;
- and
- a controller in communication with the wavelength-dependent optical interferometer, the controller configured to measure a tear film aqueous plus lipid layer relative reflectance spectrum using the wavelength-dependent optical interferometer,
- convert the measured tear film aqueous plus lipid layer relative reflectance spectrum to a calculated absolute reflectance lipid spectrum, wherein the calculated absolute reflectance lipid spectrum is calculated based on wavelength-dependent refractive indices for air, lipid, and aqueous phases and wherein the wavelength-dependent refractive indices for lipid are based upon a Sellmeier equation form, and
- compare the calculated absolute reflectance lipid spectrum to a theoretical absolute reflectance lipid spectrum to determine a tear film lipid layer thickness.
Dependencies are inferred from the claim text.