摘要:
Balanced pH, hyperosmotic, hypoosmotic, or isoosmotic gels are ideal vehicles for drug delivery. They are especially suited for topical body cavity or injection application of drugs or diagnostic agents; for drug or diagnostic agent delivery to the eye of a mammal; as protective corneal shields; or as ablatable corneal masks useful in laser reprofiling of the cornea. The compositions without the addition of a drug or diagnostic agent are useful as medical devices, for instance, in separating surgically or otherwise injured tissue as a means of preventing adhesions.
摘要:
A method of analyzing astigmatism is disclosed which enables surgeons to ascertain what surgery may be required subsequent to initial surgery to achieve the preoperative aim of the initial surgery. The method includes determining a preoperative astigmatism, defining an aimed astigmatism and determining an achieved astigmatism following initial surgery. The astigmatism values are initially determined in a zero to 180 degree range and are doubled to convert them to a 360 degree range. An aimed induced astigmatism vector, a surgically induced astigmatism vector and a difference vector are calculated. Magnitudes and angles of the vectors can be calculated to provide astigmatism magnitude values and angle values for modifying parameters of future surgery for improved performance of future surgery and for statistical analysis. The method also provides a rationale for determining a treatment parameter when spectacle and corneal astigmatism do not coincide.
摘要:
The invention contemplates an inventory of disposable elements adapted for selective placement in the path of laser-beam delivery to the cornea. Each of the disposable elements carries a membrane which is opaque to the laser beam and which is designedly subject to ablation when exposed to the laser beam, the thickness of the membrane being a precharacterized function of local area such that a given laser-beam course of exposure will require greater or lesser time to locally ablate the membrane and thus permit laser-beam exposure past the membrane and into correspondingly localized ablating impingement with the cornea. Stated in other words, varying-spot size at the cornea is achieved by a time-release function of the membrane, on a predetermined area-controlled basis that is designed to achieve the diopter change specifically identified with each particular selectable element.
摘要:
A thin, pliable mat to enhance visualization of corneal topography during rastostereography or videokeratoscopy. The mat is approximately 20 microns or less in thickness and constructed from hydrophobic material. In one preferred embodiment, the mat has a pattern etched thereon. In an alternative embodiment, a pattern is projected onto the mat. For rastostereography the pattern is a grid. For videokeratoscopy the pattern is concentric circles. The mat conforms to the surface of the cornea and the pattern is analyzed using conventional technology to determine corneal topography.
摘要:
A method of using rastophotogrammetry and Placido-disc videokeratoscopy in ophthalmological surgery to calibrate a surgical laser wherein the effect of laser ablation on various substrates is measured by performing rastophotogrammetry or Placido-disc videokeratoscopy on the substrate before and after laser ablation to determine whether there is a uniform ablation and no unwanted effects created by the laser. The substrate can be calibration block, an intraoccular lens implant, a contact lens, an artificial cornea, or cornea.
摘要:
A method and system for reshaping Bowman's membrane, which lies directly below the anterior epithelial surface of the cornea, to provide correction of refractive errors in the eye by photoablation of selective regions of the Bowman's membrane without substantial penetration into the stroma of the eye is disclosed including a laser and a beam-shaping mask, disposed between the laser and the surface of the cornea, which imposes a defined ablation profile upon the Bowman's membrane by laser radiation. The system can also include a feedback control for measuring the effectiveness of the laser during operation and for controlling the laser such that the reprofiling operation is substantially confined to the Bowman's membrane throughout the procedure. The beam-shaping mask can include either an aperture e.g., a beam-shaping stop means alone or in combination with a beam-shaping window, or an mask which is erodible or otherwise graded in its absorptive capacity to present a predefined profile of resistance to the laser radiation.
摘要:
Balanced pH, thermo-irreversible gels comprising a polyoxyalkylene compound and an ionic polysaccharide are ideal materials for the formation of a protective contact lens over the cornea of the eye of a mammal.
摘要:
The invention contemplates controlled ablation of the cornea, using ultraviolet laser radiation, wherein irradiated flux density and exposure time are so controlled as to achieve desired depth of the ablation. Sculpturing action results from precharacterized distribution of flux density across the cross-section of laser-beam projection, in the context of beam size, at cornea incidence, to match the area to be ablated, and the duration of exposure determines the extent of curvature change. Illustrative techniques and situations are disclosed, for myopia correction, for hyperopia correction, and for astigmatism correction.
摘要:
An apparatus and process for applying a synthetic lenticule to the cornea of a human eye is disclosed, the process also contemplating selective reprofiling of the lenticule while it is in place over the cornea. The process involves securing the lenticule over the cornea with an adhesive, thus leaving the visual axis of the eye undisturbed or with the peripheral edge thereof being retained by a peripheral slit. A laser delivery system is used to reprofile the lenticule if necessary for refining the refractive power of the lenticule.