59 results about "Anterior cornea" patented technology

A pre-formed intrastromal corneal insert for use in treating Keratoconus and similar dystrophies and methods of using the same. An intrastromal insert of the present invention comprises a biocompatible polymer and may be used to adjust corneal curvature, thereby correcting vision abnormalities caused by disease or other surgical procedures. The insert may be comprised of a circular or semi-circular ring shape or a portion of a ring, or “arc”, encircling the anterior cornea within the frontal circumference of the cornea. The insert may be used in multiples to form complete arcs or to form constructs of varying thicknesses. The insert of the present invention possesses a cross section that results in a low scattering level of light.

The present invention discloses a method for characterizing ectatic diseases of the cornea by computing a mean curvature map of the anterior or posterior surfaces of the cornea and fitting the map to a Gaussian function to characterize the surface features of the map. Exemplary ectatic disease that may be characterized include keratoconus and pellucid marginal degeneration. Also disclosed are a system for diagnosing ectatic disease of the cornea and a computer readable medium encoding the method thereof.

“Universal improvement” of vision is achieved by effectively changing the shape of the anterior refracting surface of the cornea to an ideal “turtleback” shape, on which is imposed the necessary curvature adjustment to achieve correction of distance vision. In accordance with one embodiment, the cornea is actually formed to the turtleback shape through corneal surgery, preferably laser ablation surgery. In accordance with a second embodiment, a contact lens with the desired distance corrected ideal turtleback shape on its anterior surface is positioned over the cornea.

The invention provides a corneal thickness measuring method based on subdivision of pulses, which belongs to an ultrasonic thickness measuring method. Measurement precision of the corneal thickness measuring method can achieve the micrometer level. Subdivision of pulse is realized by the aid of phase shift of a transmitted pulse, an ultrasonic signal which is reflected back is received, the frontwall and the rear wall of a cornea are judged, a single measurement result is calculated, a next transmitted pulse shifts by a subdivided phase of a pi phase, an ultrasonic signal which is reflected back is received, a current measurement result is obtained, and after total transmitted pulses shift by the pi phase, a last measurement result is obtained. Accurate distances from two sides of the cornea to an ultrasonic sensor are calculated according to the phases corresponding to the maximum values of all the subdivision results, and the final cornea thickness value is obtained by means of subtracting the two accurate distances. If subdivided steps are N, measurement precision is 1 / N of semi-wavelength. The corneal thickness measuring method has the advantages that the ultrasonic thicknessmeasuring method is realized by the aid of subdivision of pulses, the measurement precision can achieve the micrometer level. Resolution ratio of the method is high, center frequency of a probe does not need to be too high, and the corneal thickness measuring method is easy to be popularized.

Methods of correcting vision for presbyopia, including remodeling a stroma with a laser to create an intracorneal shape, where the corneal shape includes a central region with a thickness that is about 50 microns or less measured from an extension of a shape of a peripheral region of the corneal shape, wherein remodeling a portion of the stroma increases a curvature of a central portion of the anterior surface of the cornea with a central elevation change for near vision.

A method of selecting a toric lens by taking into consideration the magnitude and orientation of the posterior cornea and / or the location of the incision axis is described. The magnitude and orientation of the posterior cornea can be calculated as a function of the measured pre-operative orientation of the steep meridian of the anterior cornea.

The present disclosure describes an orthokeratology lens for myopia control, the orthokeratology lens having an inner surface configured to alter the distribution of epithelial cells on the anterior surface of the cornea, and an outer surface opposite the inner surface, the inner surface from the center outward A basal arc area, an inversion area, and a fitting area are continuously formed. The basal arc area is configured to be an aspherical shape in which epithelial cells on the front surface of the cornea migrate from the central portion of the cornea to the mid-peripheral portion of the cornea. The basal arc area has a central area and a surrounding area. A peripheral area of ​​the central area, the radius of curvature of the central area is smaller than the radius of curvature of the peripheral area, the inversion area is configured to have a shape to receive the corneal anterior surface epithelial cells migrating from the central portion of the cornea to the mid-peripheral portion of the cornea, and the fitting area has The site that contacts and locates the cornea. According to the present disclosure, it is possible to provide an orthokeratology lens for myopia control with an aspherical surface design to facilitate the formation of an effective myopic defocus amount.

Provided are systems and methods for correcting a corneal surface irregularity surface in a subject. The system generally comprises a infrared laser, for example, and infrared laser and a laser control unit, a corneal contacting unit, a gel solidifying unit and an electronic device tangibly storing algorithms to operate the units. In the methods, a polymerizable or thermo-reversible gel or polymerized resin is applied to the anterior corneal surface and solidified as a layer over the cornea. A first correcting cut is lasered into the stroma of an applanated cornea, the gel layer is then removed and a second correcting cut is lasered in the stroma of the applanated cornea. The lenticule formed intrastromaly by the first and second correcting cuts is removed such that the cornea has a corrected corneal curvature.