95 results about "Corneal curvature" patented technology

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.

The invention relates to devices and methods for selecting IOLs for implantation and eye models useful with the methods. One method comprises the steps of determining the axial eye length, the pupil size at a desired light level; the desired postoperative refraction; determining an aspheric representation of the corneal curvature and determining the location of the plane of fixation of the IOL following implantation.

A corneal-scleral orthokeratology contact lens is formed of rigid gas permeable material with uniform arc lengths in the treatment area even when the corneal curvature varies and asymmetric blends or splines called minor zones, where the portion of the blend or spline is shorter toward the lens center and broader toward the lens edge, and relieve the treatment area of all centering responsibility, transferring it to the limbal-scleral region. The method of determining the total sagittal height of an eye at a given chord diameter to predetermine exact fitting parameters and predict unaided visual outcome trial lenses, with exact chord and sagittal height values used to match the sagittal height of an eye, the sagittal value may be obtained from some ocular topographers. A computer program can easily take the sagittal information and design an optimum lens.

Combined equipment for non-contacting determination of axial length (AL), anterior chamber depth (VKT) and corneal curvature (HHK) of the eye are also important for the selection of the intraocular lens IOL to be implanted, particularly the selection of an intraocular lens IOL to be implanted, preferably with fixation of the eye by means of a fixating lamp and/or illumination through light sources grouped eccentrically about the observation axis.

An ophthalmic method for determining a relationship between aphakic ocular power and estimated effective lens position (ELP) of an intraocular lens (IOL) to be implanted in a patient's eye. The method can be used to determine an estimate of the ELP of an IOL given the aphakic ocular power of the patient's eye, for example, without measurement of the corneal curvature or axial length of the patient's eye. The estimate of ELP can then be used to determine a suitable value of optical power for the IOL to be implanted in the patient's eye.

A method and apparatus for adjusting corneal curvature of the eye comprising an adjustable corneal arcuate segment or segments which is implantable into the cornea. The arcuate segment is a flexible hollow shell composed of a synthetic or a natural material, with an annular chamber that is filled with a predetermined amount of a biocompatible material. The corneal curvature is adjusted by removing or augmenting the predetermined amount of biocompatible material contained in the arcuate segment.

A method for stabilizing collagenous eye tissues by nitrite and nitroalcohol treatment. The topical stiffening agent contains sodium nitrite or a nitroalcohol in a buffered balanced salt solution and can be applied to the surface of the eye on a daily basis for a prolonged period. Application of the solution results in progressive stabilization of the corneal and scleral tissues through non-enzymatic cross-linking of collagen fibers. The compounds can penetrate into the corneal stroma without the need to remove the corneal epithelium. In addition, ultraviolet light is not needed to activate the cross-linking process. The resulting stabilization of corneal and scleral tissues can prevent future alterations in corneal curvature and has utility in diseases such as keratoconus, keratectasia, progressive myopia, and glaucoma.

Examples of systems and methods for determining a limbic boundary of an iris of an eye are provided. Properties of the corneal bulge can be computed from eye images. An intersection of the corneal bulge with the eye surface (e.g., sclera) can be determined as the limbic boundary. The determined limbic boundary can be used for iris segmentation or biometric applications. A head mounted display can include a camera that images the eye and a processor that analyzes the eye images and determines the limbic boundary.

A method for modifying the curvature of a live cornea to correct a patient's vision. The live cornea is first separated into first and second opposed internal surfaces. Next, a laser beam or a mechanical cutting device can be directed onto one of the first and second internal surfaces, or both, if needed or desired. The laser beam or mechanical cutting device can be then used to incrementally and sequentially ablate or remove a three-dimensional portion of the cornea for making the cornea less curved. An ocular material is then introduced to the cornea to modify the curvature. The ocular material can be either a gel or a solid lens or a combination thereof. In one embodiment, a pocket is formed in the central portion of the cornea to receive an ocular material. In another embodiment, a plurality of internal tunnels are formed in the cornea to receive the ocular material. The ocular material can be either a fluid such as a gel or a solid member. In either case, the ocular material is transparent or translucent, and can have a refractive index substantially the same as the intrastromal tissue of the cornea or a different refractive index from the intrastromal tissue of the cornea.

Surgical apparatus for inserting a plastic, split end, adjusting ring into the stroma of the cornea of the eye wherein the adjusting ring includes, as a part thereof, a dissecting head to part the stroma and provide a pathway for the adjusting ring as the ring is rotated. The ends of the adjusting ring are moved to change the shape of the cornea to a desired shape in accordance with the desired visual correction after which the ends of the adjusting ring are fixably joined to maintain the desired shape.

Methods and apparatus can fit coverings to treat eyes. The covering can be identified so as to provide improved flow of tear liquid under the covering. The covering can be identified based on an inner corneal curvature and an outer corneal curvature and one or more of a limbus sag height or a conjunctival sag height. The covering may form a chamber when placed on the eye to pump tear liquid under at least a portion of the covering. The covering may comprise an outer portion with rigidity to resist movement on the cornea and an inner portion to contact the cornea and provide an environment for epithelial regeneration. The covering may comprise a material having high oxygen permeability, for example silicone, with a wettable coating disposed on at least an upper surface of the coating.

A corneal topography analysis system includes: an input unit for inputting corneal curvature data; and an analysis unit that determines plural indexes characterizing topography of the cornea based on the input corneal curvature data, the analysis unit further judges corneal topography from features inherent in predetermined classifications of corneal topography using the determined indexes and a neural network so as to judge at least one of normal cornea, myopic refractive surgery, hyperopic refractive surgery, corneal astigmatism, penetrating keratoplasty, keratoconus, keratoconus suspect, pellucid marginal degeneration, or other classification of corneal topography.

An auto refracto-keratometer not only produces a black-and-white image for observing the alignment of eyes to be examined using an infrared illumination light but also has a color observation optical system for observing a condition of eyes to be examined using color-illumination light. The auto refracto-keratometer comprises an infrared optical system for examining an alignment and corneal curvature of eyes to be examined; a fogging optical system for relaxing accommodation of the eyes; a measuring optical system for measuring refractive power of the eyes; and a color observation optical system having a visible light source for emitting at least one visible light to the eyes and a 2-dimensional imaging device for detecting image of visible light reflected by the eyes.

The present invention provides apparatus and techniques for performing prolate shaped corneal reshaping using an ellipsoid corneal modeler. In accordance with the principles of the present invention, an ellipsoid corneal modeler is implemented with the well behaved conicoid, combined with a modeled surface which can be used for astigmatic treatments. An ellipsoid corneal modeler includes an ellipsoid fitter which utilizes two radii of curvature, asphericity (Q), and a surface rotation about the pupil center (roation of theta), yielding the equation: <math-cwu id="MATH-US-00001"> <number>1</number> $\begin{array}{cc}\frac{x^2}{R_x}+\frac{y^2}{R_y}+\frac{z^z}{\left(\frac{2R_x{R}_y}{\left(1+Q\right)R_x+R_y}\right)}=\frac{2R_x{R}_y}{\left(1+Q\right)R_x+R_y}& \left(5\right)\end{array}$ <mathematica-file id="MATHEMATICA-00001" file="US20020115988A1-20020822-M00001.NB"/> <image id="EMI-M00001" wi="216.027" he="30.9582" file="US20020115988A1-20020822-M00001.TIF" imf="TIFF" ti="MF"/> </math-cwu> Moreover, a conversion is provided to convert between measurements obtained by a keratometer, and apical radii. In a further embodiment provided by the present invention, conversion is made possible between radii measurements obtained clinically (e.g., using a keratometer) and radii measurements at the apex, i.e., keratometric to apical radius conversion.

The present invention relates to an intrastromal corneal device for reshaping the curvature of the cornea comprising a substantially circular structure having a convex surface provided with openings for biological exchange between the layers of the cornea, said substantially circular structure comprising the shape of a circular segment or of a spherical/aspheric cap provided or not with a central opening. Said device further comprises means for promoting the reshaping of the cornea, so that it assumes a curvature closer to the intended curvature, thus providing a significant reduction of visual disturbances caused by corneal ectatic conditions such as keratoconus.

The invention relates to a device for measuring corneal curvature. The device for measuring the corneal curvature comprises a double ring measurement light source, an image acquisition system and an image process and control system. The double ring measurement light source comprises an inner ring point light source and an outer ring measurement light source, wherein the inner ring point light source emits point-shaped focus light spots to the cornea of an eye, and the outer ring measurement light source emits ring-shaped measurement light to the cornea of the eye. The image acquisition system collects and detects the point-shaped focus light spot image and ring-shaped image reflected by the cornea. The image process and control system obtains the gray level change rate K of different point-shaped light spots of the point-shaped focus light spot image detected by the image acquisition system, confirms whether the detected eye is measured within an allowable range, compensates the ring-shaped image and guides the compensation direction if the eye is not measured within the allowable range and computes the corneal curvature of the detected eye according to the radius R of the compensated ring-shaped image. The invention further provides a method for measuring the corneal curvature with the device. The method for measuring the corneal curvature is simple, and an operator can find the best measurement position quickly as long as the operator follows the guide of an instrument output device.

The invention relates to a corneal curvature measuring device based on a telecentric light path system. The corneal curvature measuring device is composed of an objective lens device, a light spot collimation device, a target ring illuminating device, a target ring device, a monitoring beam splitter device, a monitoring system device and a base board. The objective lens device comprises an objective lens fixing base, an objective lens cone and an objective lens. The light spot collimation device comprises a light spot collimation lens cone, a light source circuit board, a light emitting diode, a diffuser, a small aperture and a collimation lens. The target ring illuminating device comprises a target ring illuminating circuit board and at least three illuminating light emitting diodes. The target ring device comprises a target ring fixing support, a target ring and a target ring protection piece. The monitoring beam splitter device comprises a monitoring beam splitter base and a monitoring beam splitter. The monitoring system device comprises a monitoring fixing support, a monitoring lens cone, a monitoring lens and an aperture pressing cylinder. According to the corneal curvature measuring device, the measuring accuracy of the corneal curvature and the focusing speed of a full-automatic computer optometry unit are greatly improved.