Other

Cylite Pty Ltd

Alcon, Inc.

Grant Andrew Frisken

Steven James Frisken

Trevor Bruce Anderson

Armin Georg Segref

Apparatus and methods are presented for non-contact in-vivo measurement of one or more properties of a cornea or tear film with spatial resolution. In certain embodiments the cornea/tear film is probed at substantially normal incidence with a converging array of beamlets from a multi-wavelength optical source, and the reflected light analysed interferometrically to generate a time sequence of pachymetry maps. Thickness variations arising from differences between the external and intraocular pressure, e.g. from the ocular pulse or externally applied pressure changes, are measured and analysed to obtain information on a biomechanical response of the cornea. In preferred embodiments the time variation in tear film thickness is measured and subtracted to yield normalised pachymetry data for the biomechanical analysis. In certain embodiments the apparatus is configured to measure the dynamics and profile of the tear film, using either converging or substantially parallel arrays of beamlets.

Apparatus and method for in-vivo measurement of corneal biomechanical response

Methods and apparatus are provided for optical coherence metrology or tomography across an extended area of an eye with improved registration. At least two optical coherence tomograms are acquired, with each tomogram containing data from regions of an anterior surface of the eye that are at least partially overlapping, and data from one or more deeper structures such as the retina or the anterior or posterior lens surfaces. The tomograms are then processed to register the data from the overlapping portions of the anterior surface regions, thereby registering the data from the deeper structures. In certain embodiments the reference arm of the apparatus comprises a compound reflector having at least two axially separated reflective surfaces for applying differential delays to different portions of the reference beam. The depth of field of the apparatus is thereby extended to enable measurement of eye length. In certain embodiments eye length measurements at a number of angles of incidence provide information on total eye shape.

Optical coherence metrology and tomography with improved registration

Methods and apparatus are presented for obtaining high-resolution 3-D images of a sample over a range of wavelengths, optionally with polarisation-sensitive detection. In preferred embodiments a spectral domain OCT apparatus is used to sample the complex field of light reflected or scattered from a sample, providing full range imaging. In certain embodiments structured illumination is utilised to provide enhanced lateral resolution. In certain embodiments the resolution or depth of field of images is enhanced by digital refocusing or digital correction of aberrations in the sample. Individual sample volumes are imaged using single shot techniques, and larger volumes can be imaged by stitching together images of adjacent volumes. In preferred embodiments a 2-D lenslet array is used to sample the reflected or scattered light in the Fourier plane or the image plane, with the lenslet array suitably angled with respect to the dispersive axis of a wavelength dispersive element such that the resulting beamlets are dispersed onto unique sets of pixels of a 2-D sensor array.

High resolution 3-D spectral domain optical imaging apparatus and method

Method and systems are presented for analysing a wavefront using a spectral wavefront analyser to extract optical phase and spectral information at a two dimensional array of sampling points across the wavefront, wherein the relative phase information between the sampling points is maintained. Methods and systems are also presented for measuring an eye by reflecting a wavefront of an eye and measuring the wavefront at a plurality of angles to provide a map of the off-axis relative wavefront curvature and aberration of the eye. The phase accuracy between wavelengths and sample points over a beam aperture offered by these methods and systems have a number of ocular applications including corneal and anterior eye tomography, high resolution retinal imaging, and wavefront analysis as a function of probe beam incident angle for determining myopia progression and for designing and testing lenses for correcting myopia.

Ocular metrology employing spectral wavefront analysis of reflected light

Methods and apparatus are presented for obtaining high-resolution 3-D images of a sample over a range of wavelengths, optionally with polarization-sensitive detection. In preferred embodiments a spectral domain OCT apparatus is used to sample the complex field of light reflected or scattered from a sample, providing full range imaging. In certain embodiments structured illumination is utilized to provide enhanced lateral resolution. In certain embodiments the resolution or depth of field of images is enhanced by digital refocusing or digital correction of aberrations in the sample. Individual sample volumes are imaged using single shot techniques, and larger volumes can be imaged by stitching together images of adjacent volumes. In preferred embodiments a 2-D lenslet array is used to sample the reflected or scattered light in the Fourier plane or the image plane, with the lenslet array suitably angled with respect to the dispersive axis of a wavelength dispersive element such that the resulting beamlets are dispersed onto unique sets of pixels of a 2-D sensor array.

Method and systems are presented for analyzing a wavefront using a spectral wavefront analyzer to extract optical phase and spectral information at a two dimensional array of sampling points across the wavefront, wherein the relative phase information between the sampling points is maintained. Methods and systems are also presented for measuring an eye by reflecting a wavefront of an eye and measuring the wavefront at a plurality of angles to provide a map of the off-axis relative wavefront curvature and aberration of the eye. The phase accuracy between wavelengths and sample points over a beam aperture offered by these methods and systems have a number of ocular applications including corneal and anterior eye tomography, high resolution retinal imaging, and wavefront analysis as a function of probe beam incident angle for determining myopia progression and for designing and testing lenses for correcting myopia.

Interferometry-based methods and apparatus are presented for analyzing one or more wavefronts from a sample, in which the sample wavefronts are interfered with two or more reference wavefronts to produce two or more interferograms in a sufficiently short time period for the interferograms to be captured in a single exposure of an image capture device such as a CCD array. Each interferogram has a unique carrier frequency dependent on the angle between a respective pair of sample and reference wavefronts. In certain embodiments multiple sample and/or reference wavefronts are generated using scanning mirrors, while in other embodiments utilizing multi-wavelength beams multiple sample and/or reference wavefronts are generated with wavelength dispersive elements. The methods and apparatus are suitable for measuring aberrations at one or more positions on the retina of an eye.

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Mitcham, Australia

Grant Andrew Frisken