Abstract: An ophthalmic system for use in performing angular measurements in relation to a patient's eye. The ophthalmic system can include an optical angular measurement device that can provide angular indicia by, for example, projecting an image of an angular measurement reticle onto a patient's eye or by superimposing an image of an angular measurement reticle onto an image of the patient's eye. The ophthalmic system can include an optical refractive power measurement device for providing desired angular orientations for ocular implants or for incisions. The ophthalmic system can be used, for example, to align a toric intraocular lens to a desired angular orientation.

Abstract: Methods and systems for obtaining an ocular aberration measurement of an eye of a patient are provided. Exemplary techniques involve obtaining a first induced metric for the eye that corresponds to a first accommodation state of the eye, obtaining a second induced metric for the eye that corresponds to a second accommodation state of the eye, and determining a natural metric of the eye based on the first and second induced metrics. An induced metric may include a pupil size or a spherical aberration. Techniques can also include determining a target metric for the eye base on the natural metric, determining whether an actual metric of the eye meets the target metric, obtaining an ocular aberration measurement of the eye if the actual metric meets the target metric, and determining a treatment for the eye based on the ocular aberration measurement.

Abstract: A vision testing system comprises a image wavefront modulator, eye tracking system, focusing system using a spherical concave mirror, and a patient station. In various embodiments, the image wavefront modulator and the patient's eyes are positioned off axis with respect to the optical axis of the focusing mirror. Thus, optical elements in the wavefront modulator may automatically adjust to correct for aberrations introduced by the focusing system. Moreover, the optical elements may also be used to automatically correct for magnification errors introduced by movement of the patient within the patient testing station. Furthermore, the eye tracking system may be used to determine the errors introduced by movement of the patient eyes. Finally, the wavefront modulator may be used to produce an image on the patient's retina that accurately emulates an image that result if the patient was looking through a spectacle lens of a particular design during various gaze angles.

Abstract: Vision testing methods and apparatuses are disclosed, the methods including measuring the modulation to a wavefront of light imparted by a contact lens, determining the wavefront modulation necessary to emulate the optical properties of the lens as worn on a patient's eye, generating a static or dynamic image viewable by a patient, modulating the wavefront of the image remote from the patient to attain the wavefront necessary to emulate the optical properties of the lens as worn on a patient's eye, and relaying the wavefront to a plane nearby, on, or within the patient's eye.

Abstract: System and methods for testing and/or training a subject's vision and coordination abilities are provided. More specifically, the method may include testing various aspects of the subject's vision and coordination abilities, such as eye-hand coordination, split attention, reaction time, body coordination, etc. By using various tests, an efficient examination may be administered. In accordance with the invention, an individual may be subjected to such a method of testing and/or training at a unitary center capable of presenting such tests to the individual, receiving input from the individual, and processing the received input. Such a unitary test center may further be configurable, so that the tests administered may vary based on the needs of the individual. The received input may then, for example, be used to compute data related to the user's vision and coordination abilities, both overall and for each individual test.

Abstract: An ophthalmologic apparatus includes a first changing unit configured to change a size of an aperture of a diaphragm arranged in an optical path connecting a subject's eye and a light source and in a position conjugate with a pupil of the subject's eye, and a second changing unit configured to, if a signal for instructing the first changing unit to change the size of the aperture from a first size to a second size smaller than the first size is output to the first changing unit, change an amount of light of a fixation target image projected onto the subject's eye from a first light amount to a second light amount smaller than the first light amount.

Abstract: Apparatus for testing a subject's visual field includes a data processor, which can be provided by a general purpose computer, coupled to a pupil tracking system. The data processor is programmed to cause targets to be displayed at different locations on a display screen and to determine from the pupil tracking system whether the subject's pupil has moved in response to display of each target. In some embodiments, the pupil tracking system comprises an infrared camera.

Abstract: The invention relates to a system and method for measuring light diffusion in the eyeball or eye region, by recording and processing retinal images. The inventive system includes a double-pass ophthalmoscopic system having means for correcting low-order aberrations. Said system can be used to record images of the plane of the retina on a CCD camera, the outer part of said images containing information relating to ocular scattering. The aforementioned images can be used to obtain the objective scattering index (OSI), providing the ratio between the energy on the outer part of the image and the energy in the central part, or, alternatively, the modulation transfer function (MTF) area can be used for this purpose once the low frequencies have been filtered. According to the inventive method, the low-order aberrations are corrected before a retinal image or a temporal sequence of retinal images is captured and recorded.

Abstract: A surgical microscopy system comprises microscopy optics for generating an image of an eye under surgery. A pattern generator generates a pattern to be superimposed with the image. An eye-tracker is provided for tracking a position of the superimposed pattern with respect to the image in case of a movement of the eye. The superimposed pattern comprises pattern elements that are equally distributed on first and second circles of different sizes, in order to give assistance when placing a suture during a corneal transplant. The superimposed pattern may also provide an assistance for orientating a toric intra-ocular lens.

Abstract: In one embodiment a wavefront sensor is configured to measure real time aberration values of a wavefront returned from the eye of a patient while an image of the eye of the patient is being viewed by a surgeon during an on-going vision correction procedure and for providing an output signal indicating real time aberration values and a display, coupled to the wavefront sensor, is configured to show a dynamic display indicating the real time aberration values to the surgeon and configured to be viewed by the surgeon while also viewing the image of the eye of the patient during the on-going vision correction procedure.

Abstract: The aim of the present invention is to propose a diagnostic device for detecting a layer boundary which facilitates the determination of layer thicknesses in the human eye.

Abstract: An opthalmologic apparatus changes the wavelength of index light, which is projected on an eye to be examined, by selecting the light emission of a visible LED and an infrared LED, and changes the position of a split unit along an optical axis based on the selection.

Abstract: A method for noninvasive analysis of a retina includes exposing the retina to one or more first sets of at least three illumination light signals. The at least three illumination light signals each have a different wavelength. The method also includes optically collecting a reflected light signal for each of the at least three illumination light signals of the one or more first sets. Each of the reflected light signals is a portion of the respective illumination light signal reflected by the retina. The method further includes detecting the reflected light signals of the one or more first sets as a function of intensity. The method still further includes determining a first opsin density using the detected intensity of each of the reflected light signals of the one or more first sets.

Abstract: Aberration-induced vision symptoms are determined by obtaining at least one wave aberration of an eye, calculating at least one point-spread function from the wave aberration, convolving the point-spread function of eye with at least one specially designed image for night vision diagnosis, and determining at least one aberration-induced vision symptom of the tested eye from the convolved images. The specially designed images are for vision diagnosis of aberration-induced glare, halo, ghost image, and starburst. The invention methods for specifying aberration-induced symptoms allow to find an optimized refractive corrections of defocus and astigmatism and to reduce vision symptoms caused by aberrations in the eye.

Abstract: An automated ophthalmic system is disclosed that is utilized to examine the eyes of a subject. A refraction system measures a refractive error of each eye and identifies a lens to correct the refractive error detected. A display presents one or more of an optotype, a chart, a test and a function to the subject to ascertain the refractive error. An interface device receives a voltage signal from the refraction system, converts the voltage signal into one or more ASCII characters, and communicates the one or more ASCII characters to the display to present the one or more of an optotype, a chart, a test and a function.

Abstract: In order to measure a cornea with the aid of a projection (S11) of a two-dimensional reference pattern onto the cornea and of a detection (S12) of the reflection pattern reflected by the cornea by virtue of the reference pattern, a plurality of different reflection images of one or more reflection patterns reflected by the cornea are stored (S13). For points on the cornea a phase value of the reflection pattern is respectively calculated on the basis of intensities respectively measured in the stored reflection images at a pixel corresponding to the relevant point. At least one measured geometrical value of the cornea is calculated (S2) on the basis of the calculated phase value. The measurement of the cornea on the basis of a plurality of different reflection images of one or more reflection patterns reflected by the cornea enables a continuous measurement of the cornea in which corresponding pixels are acquired and evaluated for each point on the cornea.

Abstract: A method of creating a statistical model for use in predicting vision correction prescriptions for patients is disclosed. The method comprises obtaining a plurality of wavefront aberration measurements from a plurality of patient's eyes, obtaining a plurality of visual acuity measurements from the plurality of patients, applying values associated with the plurality of wavefront measurements to an input layer of a statistical model, applying values associated with the plurality of visual acuity measurements to an output layer of the statistical model, and generating a plurality of weight values associated with respective nodes of the statistical model based on the applied values associated with the plurality of wavefront measurements and corresponding values associated with the plurality of visual acuity measurements.

Abstract: A pattern-generating intraocular probe is provided that includes a cannula including a diffractive optical element (DOE), the DOE being patterned such that an on-axis illumination of the DOE produces an emitted beam forming a linear pattern; and a handpiece connected to a proximal of the cannula.

Abstract: An apparatus and method is disclosed that enables an existing handheld eye imaging device to do direct measurement on images taken from the patient eye. In a preferred embodiment, a reticle is arranged in the handheld eye imaging device so that a reticle image is superimposed on the object image. In addition to allowing the user to make measurements, the reticle superimposed eye image can also be used to align the eye with the handheld eye imaging device, be used for registering images taken at different times, and also be used for finding previously recorded points on the images for comparison purposes.

Abstract: The present invention generally provides improved devices, systems, and methods for measuring characteristics of at least one eye, and particularly for measuring the physiological changes in eyes under different viewing conditions. An exemplary embodiment provides a pupilometer which measures any changes in location of a pupil center with changes in viewing distances. As the eye often moves significantly during viewing, the pupil center location will often be measured relative to a convenient reference of the eye such as an outer iris boundary. Pupil size may also be recorded, and the measurements from both eyes of a patient may be taken simultaneously. Exemplary embodiments may be configured so as to allow the vergence angle between the eyes to vary with differing viewing distances, regardless of whether one or both eyes are being measured.

Abstract: Provided are systems operable to effect a temporary change in a modulation transfer function (MTF) of a target imaging system. The systems include a light source operable to produce light for transient propagation onto at least a portion of the target imaging system, a power source in operative communication with the light source and configured to effect the production of light from the light source, and a transmission unit in operative communication with the light source and configured to propagate the produced light onto at least a portion of the target imaging system. The propagated light is configured for absorbance by the portion of the target imaging system; the absorbance causes an increase in temperature and a change in a refractive index profile of at least the portion of the imaging system. The change in refractive index profile produces a temporary change in the MTF of the imaging system.

Abstract: The present solution is directed to the orientation of an eye for diagnostic and/or therapeutic purposes, wherein the line of sight need not coincide with the optical axis of the examination apparatus or treatment apparatus. The invention includes a fixating light source for generating a positionable fixating mark, a device for coupling this fixating mark into a beam path of an ophthalmological apparatus whose imaging optics project the fixating mark on the eye to be examined and/or treated, and a control unit by which the image of the fixating mark can be displayed at different distances and angular positions with respect to the optical axis of the ophthalmological apparatus so that the eye to be examined and/or treated is oriented to this fixating mark by foveal focusing and occupies a defined position with respect to the optical axis of the ophthalmological apparatus.

Abstract: Methods and systems for obtaining an ocular aberration measurement of an eye of a patient are provided. Exemplary techniques involve obtaining a first induced metric for the eye that corresponds to a first accommodation state of the eye, obtaining a second induced metric for the eye that corresponds to a second accommodation state of the eye, and determining a natural metric of the eye based on the first and second induced metrics. An induced metric may include a pupil size or a spherical aberration. Techniques can also include determining a target metric for the eye base on the natural metric, determining whether an actual metric of the eye meets the target metric, obtaining an ocular aberration measurement of the eye if the actual metric meets the target metric, and determining a treatment for the eye based on the ocular aberration measurement.

Abstract: An arrangement for carrying out a surgical treatment of an eye includes a diagnostic instrument which is adapted to register eye-structure data. A data processing unit is adapted to generate, on the basis of the eye-structure data registered by the diagnostic instrument, a structural image that contains at least one mapping of a characteristic eye structure and also at least one positional marking arranged relative to the mapping of the characteristic eye structure. An image-data fade-in device is adapted to fade the structural image generated by the data processing unit into an image generated by a surgical microscope during the implementation of a surgical treatment of the eye.

Abstract: The invention relates to an ophthalmic analysis system and a method for measuring a geometry of an eye to be examined using the ophthalmic analysis system that comprises a first interferometric analysis system and a second non-interferometric analysis system. The first analysis system is used for obtaining measured data on optical boundary surfaces of the eye located on a measurement axis, and measured data describing relative distances, and the second analysis system is used for obtaining at least one set of image data on optical boundary surfaces located on the measurement axis. A processing device of the ophthalmic analysis system processes the measured data and the set of image data and corrects the set of image data using the measured data.

Abstract: Process and system for determining the topography of bioelectric response signals of a visual system including a patient's retina, optical nerve or a projection thereof at the level of the central cortex, following visual stimulation through a surface arranged in front of the patient's eye. An image which comprises a plurality of cells is displayed as stimuli, each cell being activated or deactivated according to a corresponding digital time function represented by a cyclical succession of binary m-sequences of duration (T) formed from a plurality of activation symbols (N). Symbols N have a duration (Ts), and the m-sequences of the various cells are obtained cyclically from a mother m-sequence. The process determines the total bioelectric response of the visual system. The response associated with each cell is determined by the total response of the visual system using a cross-correlation with a suitable translated version of a mother m-sequence.

Abstract: A method for measuring the dynamic behavior of an optical system is aimed at rendering the dynamic behavior of the optical system objectively detectable. To this end, the optical system to be measured is stimulated by stimuli whereby causing it to react, and the reaction is detected by means of a wave front analysis.

Abstract: Methods and systems for image registration implementing a feature-based strategy that uses a retinal vessel network to identify features, uses an affine registration model estimated using feature correspondences, and corrects radial distortion to minimize the overall registration error. Also provided are methods and systems for retinal atlas generation. Further provided are methods and systems for testing registration methods.

Abstract: With some ophthalmological instruments, the patient to be examined or treated needs to gaze in a defined direction. Accordingly, the operator needs the most objective possible information as to whether the patient actually fixates the fixating target or when this may no longer be the case. The invention makes it possible to monitor fixation economically with a short reaction time and with high accuracy. Monitoring of the fixation of an eye is accomplished in an economical manner with a short reaction time and high accuracy through spectroscopic detection of fixation, particularly by identifying a reflection at the fovea or foveola based on different reflectance factors compared to the rest of the retina.

Abstract: Provided is a hybrid laser ophthalmoscope comprising a laser light source, a LED light source, and a holographic diffuser, wherein the holographic diffuser is configured to shape a beam of light into a Maxwellian ring.

Abstract: An opthalmological measurement apparatus (1) is proposed which comprises a first measurement system and a second measurement system. The first measurement system comprises a first light projection system for projection of a first light beam (2) through a cross-sectional part (4) of an eye (3). In addition, the first measurement system comprises image detection means, arranged in the Scheimpflug configuration with respect to the first light beam (2), for detection and storage of a cross-sectional image (30A) of at least one subregion of the cross-sectional part (4) which is illuminated by the first light projection system, from a first position outside the first light beam (2). The second measurement system comprises a second light projection system for projection of a second light beam onto the eye (3), and comprises a wavefront detector (19) for determination and storage of a wavefront profile of the second light beam reflected by the eye (3).

Abstract: An eye examination device has a fundus observation system and an optical stimulation system. The optical stimulation system has an optical targeting subsystem and an optical stimulation subsystem, wherein the optical stimulation system is structured to be used to provide light stimulation to a portion of a fundus of an eye targeted by the optical targeting subsystem in conjunction with observations made with the fundus observation system.

Abstract: Provided is an ophthalmologic apparatus capable of measuring a refractive state in a state where a pupil diameter dimension varies with respect to an eye to be examined, the ophthalmologic apparatus including a measurement optical system capable of measuring distribution of an optical characteristic within a pupil diameter of the eye to be examined, the ophthalmologic apparatus including a visible light illuminator for illuminating the eye to be examined with visible light along an optical axis of the measurement optical system. The visible light illuminator is configured to be capable of changing an illuminating light intensity in a range including at least from a light intensity capable of exposing the eye to be examined to brightness equivalent to that, in a nighttime environment to a light intensity capable of exposing the eye to be examined to brightness equivalent to that in a daytime environment.

Abstract: An ophthalmologic imaging apparatus that captures a fundus image of a subject's eye includes a first extraction unit configured to extract, from a first fundus image photographed with a first light quantity, an image of a first area having intensity not less than predetermined intensity and an image of a second area other than the first area, a second extraction unit configured to extract an image of an area corresponding to the first area from a second fundus image photographed with a second light quantity based on the light quantity of the first area, a third extraction unit configured to extract an image of an area corresponding to the second area from a third fundus image photographed with a third light quantity based on the light quantity of the second area, and an image combining unit configured to combine the images extracted by the second and the third extraction units.

Abstract: Example embodiments include a dynamic wavefront sensor, a controllable wavefront offsetting element and a controller that controls the controllable wavefront offsetting element to offset selected non-plane wave aberration components in order to allow remaining non-plane wave aberration components to be more efficiently detected and measured.

Abstract: A fundus camera includes an optical path splitting unit arranged between a focusing unit and an imaging unit. The splitting unit has characteristics adapted to reflect light of a visible light region and to transmit near-infrared light. The splitting unit retreats from an optical path when a still fundus image is photographed. A quick-return mirror having such characteristics is used as the splitting unit. When near-infrared illumination light having a wavelength of about 850 nm is used, such light can be incident upon the imaging unit without loss of the amount of light. Visible light output from an internal fixation target is projected onto a subject's eye. A cornea diaphragm and a crystalline lens diaphragm are used for observing a fundus with invisible light. Each of the cornea diaphragm and crystalline lens diaphragm can be changed to another one having a different diameter.

Abstract: Provided herein are methods and systems to screen for subjects at risk for retinal-associated eye diseases or to monitor the progression/regression thereof. Generally, the method comprises simultaneously or sequentially displaying to a potentially at-risk individual targets of parallel and nonparallel lines, obtaining an orientation discrimination threshold based on the subject's selections and correlating an increase in the threshold compared to that of a normal control or to a previous threshold measured for the subject as indicative of risk for a retinal-associated eye disease or a progression of the eye disease. Also provided are program storage devices and computer program products effective to store instructions or source code to perform the methods.

Abstract: A non-contact ultrasonic tonometer for measuring intraocular pressure of an examinee's eye, in non-contact manner by use of an ultrasonic wave comprises: a probe including a vibrator for making the ultrasonic wave incident on the examinee's eye and a sensor for detecting the ultrasonic wave reflected from the examinee's eye; and an observation optical system for observing an anterior segment of the eye, wherein the probe is placed in an optical path of the observation optical system, and the observation optical system forms an image of the anterior segment through a surrounding region of the probe.

Abstract: An ophthalmic apparatus includes: a fundus observation optical system for observing a fundus; a target presenting device including a scanning member for two-dimensionally scanning a visible laser beam emitted from a laser source, the device being configured to control emission of the laser source during two-dimensional scanning by the scanning member to project predetermined target on the fundus under observation through the fundus observation optical system; and control means to change an irradiation diameter of the laser beam by inserting/removing an optical member into/from an irradiation optical path of the laser beam or moving the optical member in an axial direction and to change resolution of the target by changing each scan range of the laser beam by the scanning member according to the changed irradiation diameter of the laser beam. Accordingly, in the ophthalmic apparatus used in close and face-to-face position to an examinee, the size and shape of a target to be presented can be easily set.

Abstract: An eye refractive power measurement apparatus measures both eye refractive powers in cases where a pupil is small and large in diameter with ease. This apparatus includes: a measuring optical system causing an imaging device to capture a ring-shaped image based on measurement light reflected from a fundus of an examinee's eye; a light deflecting member arranged at a position, which is not conjugated with a pupil of the examinee's eye, on an optical path of the measuring optical system; a rotor causing the light deflecting member to rotate about an optical axis of the measuring optical system; and an eccentricity amount changer changing an amount of eccentricity of the measurement light, which is rotated eccentrically on a surface of the pupil, with respect to a center of the pupil, in order to change a region, where the measurement light passes, on the surface of the pupil.

Abstract: An ophthalmological measuring device for determining geometric structures in an eye includes an optical, triangulating measurement system for determining at least one geometric reference in the eye by triangulation, and an optical, interferometric measurement system for determining geometric detailed structures in the eye by optical interferometry. The measuring device is designed to position the geometric detailed structures determined by the interferometric measurement system on the basis of the at least one geometric reference in the eye determined by the triangulating measurement system.

Abstract: A vision testing system and method to assess vision function. In one embodiment, the vision testing system comprises: (1) a display; (2) a computer coupled to the display and configured to provide dynamic images, each including a substantially constant fixed point of fixation; and (3) a human input device coupled to the computer, wherein responses from a test subject are fed back to the computer to assess the test subject's vision function.

Abstract: An ocular light stimulus apparatus provides the ocular fundus of an examinee's eye under examination with observation light to observe the ocular fundus and provides localized background light and stimulus light to a retina of the ocular fundus to perform biological examination through use of a bioelectrical signal from the retina. The ocular light stimulus apparatus has a ring slit and a photographic stop. Each of the ring slit and the photographic stop is disposed in a position substantially conjugate with the anterior ocular segment of the eye to be examined so that the ocular fundus of the eye is irradiated with the ocular fundus observation light via the ring slit and is irradiated with the stimulus light and the background light via the photographic stop.

Abstract: An eye measurement system may include a target that moves transverse to an optical path from the target to eye, so as to relax accommodation of the lens of the eye. The target may move transverse to the optical path on a display. The patient may be fogged while the target moves transverse to the optical path, and the target may become smaller such that the patient perceives the target to be moving away from the patient. A pupil camera may measure eye position that can be correlated with the position of the target on the display to determine that the patient has maintained fixation on the moving target. A visible measurement light beam may be pulsed subsequent to and/or during motion of the target that relaxes accommodation of the eye so as to avoid visual interference of the measurement light beam with the target on the display.

Abstract: A solution for attaining high-precision and reproducible measurements during opthalmological biometry and imaging includes an illumination unit for producing a fixation marker, a device for transmitting the light of the produced fixation marker into the eye, a measurement device and a control unit. The illumination unit includes a device for the targeted change of the beam direction of the produced fixation marker. A camera for the detection of the line of vision of the eye is connected to the control unit. The control unit determines the sufficient congruity between detected line of vision and displayed beam direction of the produced fixation marker and, in dependence of the degree of probability of the congruity, triggers a measurement. The suggested arrangement is applicable for opthalmological diagnostic devices, which exhibit a camera and a measuring system, whereby measurements can be taken in all areas of the eye.

Abstract: A device for swept-source optical coherence domain reflectometry (SS OCDR) on moveable samples, particularly human eyes, for obtaining A-scans, having a measuring range according to the sample length and having a laser light source which can be adjusted by a main wave number k0 and at least one receiver for the light dissipated from the sample, wherein the sample is illuminated on the sample surface by a measurement beam having a diameter D by way of a coupling device. The light source has a spectral line width of ?k<168 m?1 and the adjustment of the light source is carried out in ?<44 s/(D*k0).

Abstract: The present invention proposes a human eye adaptive optical visual perception training apparatus, comprising: a human eye wave aberration measurement sub-system for measuring the human eye wave aberration of a person to be tested; a human eye wave aberration correction sub-system for driving and controlling the wavefront corrector to correct the human eye wave aberration of the person to be tested based on the measured human eye wave aberration of the tested person; and a visual perception training sub-system for processing and displaying sighting targets of different spatial frequencies and different contrasts, and presenting the sighting targets to the tested person, to conduct a human eye visual function measurement process and a visual perception training process. The apparatus according to the present invention is capable of several functions including eye aberration correction, visual function measurement, visual perception training.

Abstract: A cognitive function training unit including an eye-target showing unit for showing a movable eye-target on a display disposed in front of the subject's eye, an eye movement measuring unit for measuring a position and/or movement of the subject's eye, and a judgment unit for judging whether or not the subject can fixedly look at or follow the eye-target based on the position and/or the movement of the eye-target shown on the display and the position and/or the movement of the subject's eye measured by the eye movement measuring unit, and the eye-target showing unit shows the eye-target repeatedly while changing the position and/or the movement of the eye-target according to a judgment result of the judgment unit. Therefore, it is possible to show a suitable eye-target according to a symptom of a patient, whereby it is possible to conduct training efficiently.

Abstract: An eye measurement system may include a target that moves transverse to an optical path from the target to eye, so as to relax accommodation of the lens of the eye. The target may move transverse to the optical path on a display. The patient may be fogged while the target moves transverse to the optical path, and the target may become smaller such that the patient perceives the target to be moving away from the patient. A pupil camera may measure eye position that can be correlated with the position of the target on the display to determine that the patient has maintained fixation on the moving target. A visible measurement light beam may be pulsed subsequent to and/or during motion of the target that relaxes accommodation of the eye so as to avoid visual interference of the measurement light beam with the target on the display.

Abstract: An optical measurement apparatus comprises an optical system. The optical system comprises a source and an image capture device. The source is arranged to generate, when in use, a beam of electromagnetic radiation. Further, the optical system is arranged to direct the beam of electromagnetic radiation to a location to be measured. The optical measurement apparatus also comprises a feedback arrangement arranged to receive a reflected beam from the location to be measured and to provide feedback information in response to receipt of the reflected beam, the feedback information being indicative of degree of alignment of the location to be measured with the optical system.