192 results about "Corneal surface" patented technology

A system and method for eye gaze tracking in human or animal subjects without calibration of cameras, specific measurements of eye geometries or the tracking of a cursor image on a screen by the subject through a known trajectory. The preferred embodiment includes one uncalibrated camera for acquiring video images of the subject's eye(s) and optionally having an on-axis illuminator, and a surface, object, or visual scene with embedded off-axis illuminator markers. The off-axis markers are reflected on the corneal surface of the subject's eyes as glints. The glints indicate the distance between the point of gaze in the surface, object, or visual scene and the corresponding marker on the surface, object, or visual scene. The marker that causes a glint to appear in the center of the subject's pupil is determined to be located on the line of regard of the subject's eye, and to intersect with the point of gaze. Point of gaze on the surface, object, or visual scene is calculated as follows. First, by determining which marker glints, as provided by the corneal reflections of the markers, are closest to the center of the pupil in either or both of the subject's eyes. This subset of glints forms a region of interest (ROI). Second, by determining the gaze vector (relative angular or Cartesian distance to the pupil center) for each of the glints in the ROI. Third, by relating each glint in the ROI to the location or identification (ID) of a corresponding marker on the surface, object, or visual scene observed by the eyes. Fourth, by interpolating the known locations of each these markers on the surface, object, or visual scene, according to the relative angular distance of their corresponding glints to the pupil center.

A method of designing a multifocal ophthalmic lens with one base focus and at least one additional focus, capable of reducing aberrations of the eye for at least one of the foci after its implantation, comprising the steps of: (i) characterizing at least one corneal surface as a mathematical model; (ii) calculating the resulting aberrations of said corneal surface(s) by employing said mathematical model; (iii) modelling the multifocal ophthalmic lens such that a wavefront arriving from an optical system comprising said lens and said at least one corneal surface obtains reduced aberrations for at least one of the foci. There is also disclosed a method of selecting a multifocal intraocular lens, a method of designing a multifocal ophthalmic lens based on corneal data from a group of patients, and a multifocal ophthalmic lens.

A disposable stabilization and applanation device for reconfiguring the cornea of an eye for ophthalmic laser surgery, includes an applanation lens that is disposed in a particular spatial position with respect to an incident laser beam. The applanation lens is inserted into the central opening of an attachment ring and applanates the eye in response to pressure from a lens cone. The attachment ring is coupled to the eye and includes a skirt which surrounds the applanation lens and extends outwardly therefrom to define a chamber. The skirt is formed with a groove which defines a suction channel between the attachment ring skirt and the corneal surface of an eye. A vacuum source is connected and fluid communication with the suction channel and is selectively activated to create a partial vacuum in the channel.

A method for treating presbyopia by performing ablative photodecomposition of the corneal surface. The offset image of a variable aperture, such as a variable width slit and variable diameter iris diaphragm, is scanned in a preselected pattern to perform ablative sculpting of predetermined portions of a corneal surface. The scanning is performed to ablate an optical zone sized to match the patient pupil with a peripheral transition zone outside the pupil. The shape of the ablated optical zone is different from the shape of the final optical correction on the anterior surface of the cornea. The optical zone corrects for near-vision centrally and far-vision peripherally. A movable image displacement mechanism enables radial displacement and angular rotation of the profiled beam exiting from the variable aperture. The method enables wide area treatment with a laser having a narrower beam than the treatment area, and can be used in the treatment of many conditions in conjunction with presbyopia such as hyperopia, hyperopic astigmatism and irregular refractive aberrations.

A method for the simultaneous measurement of the anterior and posterior corneal surfaces, corneal thickness, and optical aberrations of the eye. The method employs direct measurements and ray tracing to provide a wide range of measurements for use by the ophthalmic community.

A display device is mounted on and/or inside the eye. The eye mounted display contains multiple sub-displays, each of which projects light to different retinal positions within a portion of the retina corresponding to the sub-display. The projected light propagates through the pupil but does not fill the entire pupil. In this way, multiple sub-displays can project their light onto the relevant portion of the retina. Moving from the pupil to the cornea, the projection of the pupil onto the cornea will be referred to as the corneal aperture. The projected light propagates through less than the full corneal aperture. The sub-displays use spatial multiplexing at the corneal surface. Various electronic devices interface to the eye mounted display.

A method for correcting the refractive error in a cornea of an eye, including the steps of positioning an inlay on the surface of the cornea, the inlay having a first surface and a second surface, and the second surface being adjacent the surface of the cornea. Energy is applied to the inlay to ablate a portion of the first surface of the inlay by an amount adapted to correct the refractive error in the eye. The inlay is removed from the surface of the cornea, and the cornea is separated into a first corneal surface and a second corneal surface, the first corneal surface facing in a posterior direction of the eye and the second corneal surface facing in an anterior surface of the eye. The inlay is then positioned adjacent at least one of the first corneal surface and the second corneal surface.

A video Keratometer/Pachymeter comprising an array of illuminated points disposed in concentric circles around the optical axis of a television camera for definition of corneal surface contour by a method similar to the well know Placido, except that the isolated point ring format provides unambiguous back ray trace information to eliminate errors inherent in the prior art, in combination with a projected pattern of discrete points to elicit Tyndall images for definition of both anterior and posterior corneal surface by triangulation using multiple television cameras viewing the reflected and Tyndall images, substraction of a view of the eye with neither pattern superimposed as well as each pattern in sequence for isolation of the data containing points from the general clutter of background pictorial information.

Methods and systems for treating presbyopia involve ablating a corneal surface of a first eye of a patient to enhance vision of near objects through a central zone of the first eye and ablating a second eye of the patient to enhance vision of near objects through a peripheral zone of the second eye. The optical power of the first eye is increased in the central zone, while the optical power of the second eye is increased in the peripheral zone. In the first eye, a peripheral zone is used primarily for distance vision. In the second eye, a central zone is used primarily for distance vision. Systems include a laser device and a processor for directing the laser device to ablate the two eyes of the patient.

A system for applying therapy to an eye includes an applicator having a conducting element configured to direct energy from an energy source to an application end of the conducting element, where the application end has at least one eye contact portion. A positioning system positions the at least one eye contact portion in stable engagement with the eye surface. The conducting element is disposed within a housing for the applicator and at least one adjustment system is employed to move the conducting element relative to the housing. The at least one adjustment system enables controlled movement of the conducting element and the at least one eye contact portion against the corneal surface. In particular embodiments, sufficient contact between the applicator and the cornea is determined by causing applanation of the cornea. In other embodiments, at least one measurement device is employed to determine when sufficient contact has been established.

A method of smoothing irregular corneal surfaces and removing protuberances from corneal surfaces by photoablative eximer laser keratectomy is provided. Collagen compositions for use in making collagen modulators useful in photoablative procedures are described. These compositions are applied to irregular corneal surfaces in sufficient amounts to at least fill in depressions or other irregularities on a corneal surface and are converted into a modulator, as a gel or polymerized film, prior to photoablation. The collagen modulators facilitate the photoablative smoothing of irregular corneal surfaces and protect adjacent corneal tissue from undesired photoablation.

A combination of a confocal scanning laser ophthalmoscope and external laser sources is used for microphotocoagulation purposes. An opto-mechanical linkage device and beamsplitter is used to align the pivot point of the Maxwellian view of the scanning laser ophthalmoscope with the pivot point of non-scanning external laser beams. The same pivot point is necessary to minimize wavefront aberrations and to enable precise focussing of a therapeutic laser beam on the retina. An AOM and/or two-dimensional AOD can be inserted in the pathway of the Gaussian therapeutic beam to control intensity and spatial pattern of small and short-duration pulses. The location of the external laser beam on the retina is determined with the help of two synchronized detectors and image processing. One detector is used to localize moving fiducial landmarks of the retina. A second detector is used to locate on the retina the external laser aiming beam. Two different confocal apertures are used. Polarizing the aiming beam is necessary to further reduce unwanted reflections from the anterior corneal surface.

In a control program, according to which a laser-beam spot is guided, while being controlled with respect to position and time, over a cornea to be corrected photorefractively, so as to ablate a predetermined ablation profile therefrom, the effect of the angle between the laser earn and the corneal surface on the energy density of the laser-beam spot incident on the corneal surface and/or on the fraction of the laser-beam energy incident on the corneal surface which is reflected away, is taken into account when generating the control program.

Described herein are designs of intracorneal inlays to produce desired shapes of the cornea's anterior surface for correcting vision impairments. In an exemplarily embodiment, a thickness profile is defined by a difference between a desired post-operative anterior corneal surface that corrects a patient's vision impairment and the patient's pre-operative anterior corneal surface. An inlay is then dimensioned to substantially have the same thickness profile. When implanted in the patient's cornea, the thickness profile of the inlay is substantially transferred to the anterior corneal surface through the intervening corneal tissue, thereby producing the desired post-operative anterior corneal surface.

A laser-based method and apparatus for corneal surgery. The present invention is intended to be applied primarily to ablate organic materials, and human cornea in particular. The invention uses a laser source which has the characteristics of providing a shallow ablation depth (0.2 microns or less per laser pulse), and a low ablation energy density threshold (less than or equal to about 10 mJ/cm.sup.2), to achieve optically smooth ablated corneal surfaces. The preferred laser includes a laser emitting approximately 100-50,000 laser pulses per second, with a wavelength of about 198-300 nm and a pulse duration of about 1-5,000 picoseconds. Each laser pulse is directed by a highly controllable laser scanning system. Described is a method of distributing laser pulses and the energy deposited on a target surface such that surface roughness is controlled within a specific range. Included is a laser beam intensity monitor and a beam intensity adjustment means, such that constant energy level is maintained throughout an operation. Eye movement during an operation is corrected for by a corresponding compensation in the location of the surgical beam. Beam operation is terminated if the laser parameters or the eye positioning is outside of a predetermined tolerable range. The surgical system can be used to perform surgical procedures including removal of corneal scar, making incisions, cornea transplants, and to correct myopia, hyperopia, astigmatism, and other corneal surface profile defects.

A system for applying therapy to an eye selectively applies coolant to the corneal surface to minimize heat-related damage to the corneal surface during thermokeratoplasty. Embodiments may include an energy source, a conducting element, a coolant supply, and at least one coolant delivery element. The conducting element is operably connected to the energy source and extends from a proximal end to a distal end. The conducting element directs energy from the energy source to the distal end, which is positionable at the eye. The coolant delivery elements are in communication with the coolant supply and are operable to deliver a micro-controlled pulse of coolant to the distal end.

An apparatus for generating cut surfaces in the cornea of an eye in order to correct ametropia is provided, said apparatus comprising a laser unit, which can focus pulsed laser radiation into the cornea and move it therein in order to generate cut surfaces, and a control unit, which controls the laser unit for generating cut surfaces such that a predetermined lenticle to be removed is separated from the surrounding corneal material in the cornea by at least one cut surface, and that at least two mutually spaced apart cut surfaces are formed as opening cuts, each extending from the lenticle to the anterior corneal surface, the position and shape of the opening cuts being selected such that the opening cuts contribute to the correction of the ametropia of the eye or do not counteract the correction of the ametropia of the eye.

Disclosed is an optical coherence biological measurer. Parameters including corneal thicknesses, anterior chamber depths, lens thicknesses and visual axis lengths of eyes are obtained in once measurement by the aid of optical coherence measurement technology. The optical coherence biological measurer comprises a short coherence interferometry system detecting by the aid of balance, a retina splitimage focusing system, a visual axis aligning system with double fixation lamps, an optical length variable system, an eye positioning system and an auxiliary focusing system. The eye positioning system images the surface of a cornea and positions an eye, a system optical axis matches with an visual axis of the eye by the aid of the visual axis aligning system with the double fixation lamps, detecting light is respectively focused on a retina, a vitreous body and the cornea by an optical length and focus linkage device, simultaneously, optical length compensation of reference light is realized, the optical length variable system is used for realizing scanning measurement for return light signals of the retina, the vitreous body and the cornea, and the visual axis length, the vitreous bodythickness, the anterior chamber depth and the corneal thickness are calculated by the aid of output signals of a balance photoelectric detector.