Abstract: The invention provides an apparatus and method for scanning, imaging and treating the retina of an eye. The apparatus (10) comprises a source of collimated light (14), a two-dimensional scanning device (16) having two axes of rotation (16a, 16b), wherein the axes of rotation (16a, 16b) are orthogonal and substantially planar, and wherein the source of collimated light (14) and the two-dimensional scanning device (16) combine to provide a two-dimensional collimated light scan from a point source (22). The apparatus (10) further comprises a scan transfer device (18), wherein the scan transfer device (18) has two foci (18a, 18b) and the point source (22) is provided at a first focus point (18a) of the scan transfer device (18) and an eye (12) is accommodated at a second focus point (18b) of the scan transfer device (18), and wherein the scan transfer device (18) transfers the two-dimensional collimated light scan from the point source (22) into the eye (12).

Abstract: The invention provides an apparatus and method for illuminating, imaging and treating the retina of an eye. The apparatus (10) comprises at least one light source (16), wherein the at least one light source (16) is adapted to provide collimated light (20) from a plurality of point sources (22), and wherein each point source (22) lies on an arc (18), and wherein the at least one light source (16) is configured to direct collimated light (20) from each point source (22) along the radius (24) of the arc (18) towards a center point (26) of the arc (18), and wherein, in use, the apparatus (10) is arranged such that the center point (26) of the arc (18) is substantially coincident with the pupillary point (40) of the eye (14), such that collimated light (20) is transmitted from the point source (22) through the pupillary point (40) of the eye (14) to illuminate the retina (12).

Abstract: A method of determining a geometrical measurement of a retina of an eye, comprising obtaining a two dimensional representation of at least a portion of the retina of the eye (34), deriving a geometrical remapping which converts the two dimensional representation of the retinal portion to a three dimensional representation of the retinal portion (36), using one or more coordinates of the two dimensional representation of the retinal portion to define the geometrical measurement to be taken of the retina on the two dimensional representation (38), using the geometrical remapping to convert the or each coordinate of the two dimensional representation of the retinal portion to an equivalent coordinate of the three dimensional representation of the retinal portion (40), and using the or each equivalent coordinate of the three dimensional representation of the retinal portion to determine the geometrical measurement of the retina of the eye (42).

Abstract: A method of determining a measurement of at least one cell type in an eye, comprising (i) obtaining a map of the cell type in the eye, (ii) obtaining a representation of the retina of the eye, (iii) matching the eye cell type map to the representation of the retina of the eye, (iv) defining a region of interest on the representation of the retina of the eye, (v) calculating a size of the region of interest on the representation of the retina of the eye, (vi) using the matched eye cell type map and the size of the region of interest to determine a measure of the cell type in the region of interest of the retina of the eye.

Abstract: An image processing apparatus uses first and second digital vascular image data to register two images. The two images may be from different imaging modes. The first and second images are processed with a two-dimensional, directional filter (500) that has the effect of producing clusters of orthogonally adjacent image data points in which the magnitude of an intensity gradient between each orthogonally adjacent image data point is less than a predetermined value. Subsequently, common clusters are identified between the first and second image data using a corner detecting algorithm (600). The directional filter produces “stepping” features, where vascular features would otherwise appear with smooth edges. These numerous features are identified by the corner detecting algorithm and can be used (1000) for registering common clusters between the first and second image data. The filter may be a rotating Gabor filter matched to vascular features in the images.

Abstract: A laser scanning ophthalmoscope obtains images of a retina. An image is processed by (i) mapping an image along a one dimensional slice; (ii) computing a wavelet scalogram of the slice; (iii) mapping ridge features from the wavelet scalogram; repeating steps (i), (ii) and (iii) for one or more mapped image slices. The mapped ridge features from the slices are superimposed. Textural information is derived from the superimposed mapped ridge features. The analysis can be tuned to detect various textural features, for example to detect image artifacts, or for retinal pathology classification.

Abstract: A method of reducing jitter error in a laser scanning system adapted to produce a scanned image including a number of lines of an object. The method includes the steps of providing a reference object arranged such that the scanned image produced by the laser scanning system includes a reference image of the reference object, processing the reference image to calculate an error arising from non-repeatable displacement of the lines of the reference image, and adjusting at least one operating parameter of the laser scanning system in response to the calculated error.

Abstract: A laser scanning system adapted to produce a scanned image including a number of lines of an object. A method includes the steps of providing a reference object arranged such that the scanned image produced by the laser scanning system includes a reference image of the reference object, processing the reference image to calculate an error arising from non-repeatable displacement of the lines of the reference image, and adjusting at least one operating parameter of the laser scanning system in response to the calculated error.

Abstract: The invention provides a method of reducing jitter error in a laser scanning system (1) adapted to produce a scanned image comprising a number of lines of an object (18). The method comprising the steps of providing a reference object (22) arranged such that the scanned image produced by the laser scanning system (1) includes a reference image (24) of the reference object (22); processing the reference image (24) to calculate an error arising from non-repeatable displacement of the lines of the reference image (24); and adjusting at least one operating parameter of the laser scanning system (1) in response to the calculated error.

Abstract: An embodiment of the invention provides an apparatus and a method. An intensity gradient between first and second optical image data of an optical image produced by an optical scanning device is determined. The first optical image data is a first optical image pixel and the second optical image data is a second optical image pixel. An intensity gradient image comprising a plurality of intensity gradient image pixels is determined, each intensity gradient image pixel representing the magnitude of an intensity gradient. One or more anomalies in the optical image in dependence on the magnitude of the intensity gradient being greater than or equal to a threshold value is identified.

Abstract: An image processing apparatus uses first and second digital vascular image data to register two images. The two images may be from different imaging modes. The first and second images are processed with a two-dimensional, directional filter (500) that has the effect of producing clusters of orthogonally adjacent image data points in which the magnitude of an intensity gradient between each orthogonally adjacent image data point is less than a predetermined value. Subsequently, common clusters are identified between the first and second image data using a corner detecting algorithm (600). The directional filter produces “stepping” features, where vascular features would otherwise appear with smooth edges. These numerous features are identified by the corner detecting algorithm and can be used (1000) for registering common clusters between the first and second image data. The filter may be a rotating Gabor filter matched to vascular features in the images.

Abstract: An alignment apparatus and method is disclosed, for ensuring correct alignment of a patient's eye with respect to an ophthalmic or optometric instrument. Graphical objects are provided which represent an ideal and an actual position of the eye, and provide for easy and intuitive feedback to an eye care professional operating the instrument on the alignment position of the patient.

Abstract: A method of identifying anomalies in images produced using an imaging device (70). The method comprises receiving (10), (12) first and second pluralities of candidate anomalies, the candidate anomalies being identified in subsequent images produced with an imaging device. A constellation match (14), (16), (18), (19) is carried out between the first and second pluralities of candidate anomalies to identify a correlation therebetween, represented by a constellation match value. A plurality of constellation match values is determined with a different relative x-y shift between the first and second pluralities of candidate images. If a good correlation is found at a particular x-y shift then the candidate anomalies are common between the first and second images, which is indicative of the first and second images including anomalies.

Abstract: A scanning laser ophthalmoscope (SLO) for imaging the retina of an eye comprises a source (12) of collimated light, a scanning device (14, 16, 1328, 1319), a scan transfer device (20) and a detector (1310). The scan transfer device has a first focus (16) at which an apparent point source is provided and a second focus (24) at which an eye (524, 1324) may be accommodated. The scan transfer device transfers a two-dimensional collimated light scan from the apparent point source into the eye. An optical coherence tomography (OCT) system (900) is combined with the SLO, the OCT system providing OCT reference and sample beams. The OCT sample beam (902) propagates along the same optical path as of the SLO collimated light through the scan transfer device. An aberration compensator (1204, 1316) automatically compensates for systematic aberrations and/or changes in wavefront introduced by scanning elements and the scan transfer device as a function of scan angle.

Abstract: The present invention provides a scanning ophthalmoscope for scanning the retina of an eye and a method of scanning the retina of an eye. The ophthalmoscope (10) comprises a source of collimated light (12), a first scanning element (14), a second scanning element (16) and a scan relay device (18) having two foci (18a, 18b). The source of collimated light (12), the first and second scanning elements (14, 16) and the scan relay device (18) combine to provide a two-dimensional collimated light scan (21) from an apparent point source (19).

Abstract: This disclosure is directed to systems and methods for determining a correction for distortion in eye representations of an ophthalmoscope. A digital model of an optical system including the ophthalmoscope and a model eye may be constructed. The digital model may be transmitted to a ray tracing system. A ray may be passed through the optical system onto a surface of the model eye. A measurement of the ray at the surface of the model eye, with distortion, may be calculated and an angular position of a horizontal scanning element and an angular position of a vertical scanning element can be determined. Using the horizontal scanning angle and vertical scanning angle, a measurement of the ray at the surface of the model eye, without distortion, may be calculated and compared to the measurement with distortion to determine a correction for distortion in eye representations of the ophthalmoscope.

Abstract: A scanning laser ophthalmoscope for scanning the retina of an eye is provided comprising a light source emitting a beam of light, scan relay elements, wherein the light source and the scan relay elements provide a two-dimensional scan of the light beam which is transferred from an apparent point source at a pupillary point of the eye to the retina of the eye, and a static aberration correction element (30) which has a shape defined to provide correction of aberrations of at least some of the scan relay elements and a location within the ophthalmoscope chosen to provide correction of aberrations of at least some of the scan relay elements, which location maintains transfer of the beam of light from the apparent point source at the pupillary point of the eye to the retina of the eye. The present solution further provides an aberration correction element and a method of determining a shape of the aberration correction element.

Abstract: A method of determining a geometrical measurement of a retina of an eye, comprising obtaining a two dimensional representation of at least a portion of the retina of the eye (34), deriving a geometrical remapping which converts the two dimensional representation of the retinal portion to a three dimensional representation of the retinal portion (36), using one or more coordinates of the two dimensional representation of the retinal portion to define the geometrical measurement to be taken of the retina on the two dimensional representation (38), using the geometrical remapping to convert the or each coordinate of the two dimensional representation of the retinal portion to an equivalent coordinate of the three dimensional representation of the retinal portion (40), and using the or each equivalent coordinate of the three dimensional representation of the retinal portion to determine the geometrical measurement of the retina of the eye (42).

Abstract: A method of determining a correction for distortion in eye representations of an ophthalmoscope comprising (i) constructing an optical description of a system comprising the ophthalmoscope and a model eye, (ii) passing a ray through the system onto a surface of the model eye, (iii) calculating an actual measurement of the ray at the surface, (iv) determining a horizontal scanning angle and a vertical scanning angle of the system for the ray, (v) calculating an expected measurement of the ray at the surface using the horizontal scanning angle and vertical scanning angle of the system, (vi) repeating steps (ii) to (v) for a plurality of further rays, and (vii) comparing the actual measurements of the rays at the surface with corresponding expected measurements of the rays at the surface to determine the correction for distortion in eye representations of the ophthalmoscope.

Abstract: An embodiment of the invention provides an apparatus and a method. An intensity gradient between first and second optical image data of an optical image produced by an optical scanning device is determined. The first optical image data is a first optical image pixel and the second optical image data is a second optical image pixel. An intensity gradient image comprising a plurality of intensity gradient image pixels is determined, each intensity gradient image pixel representing the magnitude of an intensity gradient. One or more anomalies in the optical image in dependence on the magnitude of the intensity gradient being greater than or equal to a threshold value is identified.