33 results about "Corneal vertex" patented technology

A method and apparatus for imaging within the eye is provided whereby a component of eye position is detected using optical imaging data. Tracking eye position over time and correctly registering imaging data for scan locations or using eye position to detect decentration achieves improved imaging. In one embodiment, essentially perpendicular B-scans are imaged sequentially and the corneal arc within each B-scan is analyzed to determine the vertex of the eye. The eye vertex is tracked over pairs of perpendicular B-scans to determine eye motion. In another embodiment, the decentration in the Pachymetry map is removed by correcting for the misalignment of the center of the Pachymetry map and the actual location of the corneal vertex.

Methods and systems for determining whether an image is of a left eye or a right eye may be used to enhance laser eye surgery systems and techniques. Methods generally involve locating an iris center and / or pupil center on an image of the eye, locating a corneal vertex and / or at least one reflection on the image, and determining whether the image is of a left eye or a right eye, based on the location of the corneal vertex and / or reflection(s) relative to the iris center and / or pupil center. Systems include a laser emitting a beam of an ablative light energy and a computer processor having a computer program for determining whether the image is of a left eye or a right eye, based on a location of the corneal vertex and / or reflection(s) relative to the iris center and / or pupil center.

Methods and systems for determining whether an image is of a left eye or a right eye may be used to enhance laser eye surgery systems and techniques. Methods generally involve locating an iris center and / or pupil center on an image of the eye, locating a corneal vertex and / or at least one reflection on the image, and determining whether the image is of a left eye or a right eye, based on the location of the corneal vertex and / or reflection(s) relative to the iris center and / or pupil center. Systems include a laser emitting a beam of an ablative light energy and a computer processor having a computer program for determining whether the image is of a left eye or a right eye, based on a location of the corneal vertex and / or reflection(s) relative to the iris center and / or pupil center.

Disclosed is a method for determining the position of the eye rotation center of a subject's eye including: providing a geometric model of an eye, the eye being modeled with one sphere for the sclera and one ellipsoid for the cornea of the eye, the position of the eye rotation center being the distance between a center of the sclera and an apex of the cornea and being determined based on a set of personal parameters including a first geometric dimension of the eye, each personal parameter distinct from the position of the eye rotation center; determining a value of each personal parameter; and determining a first approximate value of eye position rotation center based on the geometric model using the personal parameters. Also disclosed is a method for calculating a personalized ophthalmic lens for the eye using such center, as well as a device implementing this method.

The invention provides a method and system for segmenting a cornea structure from an OCT (Optical Coherence Tomography) cornea image, and relates to the technical field of biomedical images. The method comprises the steps of scaling the OCT cornea image; determining the horizontal coordinate of the vertex of a cornea and the initial longitudinal coordinate of the vertex of each layer of the cornea; determining initial interfaces in a circle fitting mode; performing boundary expansion on the initial interface of each layer of the cornea according to the set neighborhood width to obtain annularregions of interest; obtaining rectangular regions of interest; respectively performing inverse processing of average grayscale difference processing and flattening processing on the rectangular regions of interest to obtain modified interfaces; respectively performing an Hough transform circle fitting operation on each modified interface based on a principle that the perpendicular bisector passesthe center of a circle to obtain the center and radius of each layer of the cornea; and respectively performing Kalman filtering of horizontal projectile motion on the modified interface of each layer of the cornea. The speed and accuracy of OCT cornea image for segmenting each layer of the cornea are improved according to the invention.

The invention discloses an OCT (Optical Coherence Tomography) system for measuring the optical path value of an axis oculi and a method. The system comprises an OCT system light source, an optical fiber coupler, a detection system, a control system, a sample arm component, a reference arm component, a cornea before-and-back position alignment component and an outer eye camera component, wherein the outer eye camera component is used for monitoring an iris of eyes under test, and an operator controls the sample arm component to adjust a corneal vertex to the main optical axis of the OCT system according to the iris; the control system is used for judging the distance from the corneal vertex to an eye objective lens, and the distance from the corneal vertex to the eye objective lens is adjusted to meet the requirement on work of the system by means of the before-and-back adjustment of the sample arm component controlled by the control system; an optical path adjusting component adjusts the optical path of the sample arm component, and thus fundi of different human eyes are matched with the optical path of a reflector of a reference arm of the system to realize the OCT imaging of the fundi; the optical path value LEye of the axis oculi of the human eye can be measured according to the formula: LEye=LRDK1toEc+S+hRetinal. According to the OCT system for measuring the optical path value of the axis oculi and the method, the corneal vertex is accurately positioned, and by combining with the fundus OCT imaging technology, the test result of the optical path value of the axis oculi of the human eye is more accurate.

The invention discloses a method for accurate alignment of a corneal vertex. The method comprises the steps that (1), the pupil of a tested person is found through iris imaging, and the center of the pupil is adjusted to be nearby the center rendezvous point of a plurality of scanning lines of a scanning device; (2), the scanning device scans the pupil of the tested person, a computer processing scanning data, and then a pupil OCT is obtained; (3), the computer computes the distance L between a center reflection column in the pupil OCT and the center line of the pupil OCT; (4), the amount of movement of the head of the tested person or the scanning device is computed according to the scanning angle theta of the scanning lines and the distance L, the head of the tested person or a probe of the scanning device is moved, and the corneal vertex of the tested person is made to accurately align with a main optical axis of a system light path. The method has the advantages that the accurate alignment of the corneal vertex is achieved, the adjusting method is simple and rapid and can be divided into automatic adjusting or semi-automatic adjusting, the adjusting modes are various, and operation is easier.

The invention is directed to a system for determining the refractive properties of an eye. The system includes a wavefront measurement device for measuring the refractive properties of the eye. The system is configured to have at least one measurement mode assigned to children, wherein the system has an input device configured to switch the system into one of the at least one measurement mode assigned to children. The system is further configured to alter at least one of a group including a default pupillary distance, a default cornea vertex distance, a default position of the wavefront measurement device, a default position and / or direction of a measurement ray of the wavefront measurement device, a default position of a forehead and chin rest assembly of the system and a fixation target when the system is switched into the one of the at least one measurement mode assigned to children.