Abstract: A polarimeter system that averages multiple retardance measurement samples to cancel the effects of system birefringence in the diagnostic path. The retardance measurement errors arising from system birefringence have a symmetry that repeats over each complete cycle of optical signal rotation cycle. This symmetry is such that averaging the four retardance measurements collected over one complete rotation cycle cancels the effects of system birefringence, leaving a mean retardance measurement free of residual polarization bias. Apparatus is provided for determining the birefringence, thickness, and fiber orientation of the nerve fiber layer at the fundus of the eye by measuring the polarization bias induced in a return beam of polarized light that is reflected at the ocular fundus from an incident beam of a known polarization state. A corneal polarization compensator cancels the birefringent effects of the cornea and other portions of the eye anterior to the fundus.

Abstract: Apparatus is provided for determining the topography, thickness, and fiber orientation of the nerve fiber layer at the fundus of the eye by measuring the polarization shift induced in a return beam of polarized light which is reflected at the ocular fundus from an incident beam of a known polarization state. A corneal polarization compensator effectively cancels the birefringent effects of the cornea and other portions of the eye anterior to the fundus, so that clinically meaningful results are produced. A method for directing a measurement beam into the eye is also disclosed.

Abstract: The magnitude and axial orientation of birefringence of the anterior and the posterior segments of the human eye are determined. The anterior segment includes essentially the combined birefringence of the cornea and the crystalline lens, and the posterior segment includes regions at the fundus. The optical axis and the magnitude of the birefringence of the anterior segment is first determined, then the birefringence of the posterior segment is nulled by a variable retarder. The birefringence of the posterior segment is then determined without interference of the birefringence of the anterior segment. The apparatus and method are applicable to the measurement of the birefringence of the retinal nerve fiber layer at the peripapillary region and the birefringence of the Henle fiber layer at the macular region of the retina.

Abstract: An apparatus is disclosed for generating data representative of a three-dimensional distribution of the light backscattering potential of a transparent or semi-transparent object such as a human eye. The apparatus includes an interferometer, both the reference beam and measurement beam of which are directed toward the object and reflected by respective reference and measurement sites thereof, such that axial motion of the object during measurement affects both beams equally. The measurement beam is raster scanned transversely across each measurement site for which data is obtained. Also, the frequency of one of the beams is shifted by a non-moving frequency shifter, such that the reflected beams combine and are modulated by a heterodyne heat frequency, which is detected when the object path difference is matched with the interferometer path difference.

Abstract: An apparatus is disclosed for generating data representative of a three-dimensional distribution of the light backscattering potential of a transparent or semi-transparent object such as a human eye. The apparatus includes an interferometer, both the reference beam and measurement beam of which are directed toward the object and reflected by respective reference and measurement sites thereof, such that axial motion of the object during measurement affects both beams equally. The measurement beam is raster scanned transversely across each measurement site for which data is obtained. Also, the frequency of one of the beams is shifted by a non-moving frequency shifter, such that the reflected beams combine and are modulated by a heterodyne beat frequency, which is detected when the object path difference is matched with the interferometer path difference.

Abstract: An apparatus for separating an image of a target into a directly scattered component and a multiply scattered component by providing a stationary field stop having a first region and associated detector confocal to a point on the target. During a first interval, a light source directs a first beam to the target and the directly scattered component is selected by the first region. During a second interval, the light source directs a second beam to the target and the multiply scattered component us selected by the first region and its associated detector. Alternatively, a light source directs a first beam to the target and the directly scattered component is selected by the first region of the field stop and its associated detector, while the second region and its associated detector select for multiply scattered light.

Abstract: An apparatus is disclosed for generating data representative of a three-dimensional distribution of the light backscattering potential of a transparent or semi-transparent object such as a human eye. The apparatus includes an interferometer, both the reference beam and measurement beam of which are directed toward the object and reflected by respective reference and measurement sites thereof, such that axial motion of the object during measurement affects both beams equally. The measurement beam is raster scanned transversely across each measurement site for which data is obtained. Also, the frequency of one of the beams is shifted by a non-moving frequency shifter, such that the reflected beams combine and are modulated by a heterodyne beat frequency, which is detected when the object path difference is matched with the interferometer path difference.

Abstract: An apparatus is disclosed for generating data representative of a three-dimensional distribution of the light backscattering potential of a transparent or semi-transparent object such as a human eye. The apparatus includes an interferometer, both the reference beam and measurement beam of which are directed toward the object and reflected by respective reference and measurement sites thereof, such that axial motion of the object during measurement affects both beams equally. The measurement beam is raster scanned transversely across each measurement site for which data is obtained. Also, the frequency of one of the beams is shifted by a non-moving frequency shifter, such that the reflected beams combine and are modulated by a heterodyne beat frequency, which is detected when the object path difference is matched with the interferometer path difference.

Abstract: Apparatus is provided for determining the topography, thickness, and fiber orientation of the nerve fiber layer at the fundus of the eye by measuring the polarization shift induced in a return beam of polarized light which is reflected at the ocular fundus from an incident beam of a known polarization state. A corneal polarization compensator effectively cancels the birefringent effects of the cornea and other portions of the eye anterior to the fundus, so that clinically meaningful results are produced. A method for directing a measurement beam into the eye is also disclosed.

Abstract: Apparatus is provided for determining the topography, thickness, and fiber orientation of the nerve fiber layer at the fundus of the eye by measuring the polarization shift induced in a return beam of polarized light which is reflected at the ocular fundus from an incident beam of a known polarization state. A corneal polarization compensator effectively cancels the birefringent effects of the cornea and other portions of the eye anterior to the fundus, so that clinically meaningful results are produced.