An interferometer for tear film measurement with sub-micron resolution

A method, comprising:

• obtaining, with an interferometry system, a point-by-point scan of a corneal surface of an eye, the point-by-point scan including at least an interference signal;
• obtain a large field-of-view of a cornea of an eye from an objective lens with a curved focal plane matched to a curvature of a corneal surface;
• performing motion correction on the point-by-point scan;
• filtering noise from the interference signal;
• separating a tear film lipid layer signal and a precorneal tear film signal from the filtered interference signal;
• determining a best fit frequency for the tear film lipid layer signal and the precorneal tear film signal;
• and
• determining a thickness of the tear film lipid layer and a thickness of the precorneal tear film based at least in part on the best fit frequency.

A system, comprising:

• an interferometry system;
• a computing device, comprising a processor and a memory;
• and
• machine-readable instructions stored in the memory which, when executed by the processor, cause the computing device to at least:
• obtain an interference signal from a corneal surface of an eye using the interferometry system;
• obtain a large field-of-view of the corneal surface from an objective lens with a curved focal plane matched to a curvature of the corneal surface;
• filter noise from the interference signal to produce a deduction signal;
• separate a tear film lipid layer signal and a precorneal tear film signal from the deduction signal;
• determine a respective best fit frequency for both of the tear film lipid layer signal and the precorneal tear film signal;
• and
• determine a thickness of the tear film lipid layer and a thickness of the precorneal tear film based at least in part on the respective best fit frequencies.