초록 ▼

Low energy, ultra-short (femptosecond) pulsed laser radiation is applied to the patient's eye in one of a number of patterns such that the exposed ocular tissue is ablated or excised through the process of optical breakdown or photodisruption in a very controlled fashion. The process can be gentle e

Low energy, ultra-short (femptosecond) pulsed laser radiation is applied to the patient's eye in one of a number of patterns such that the exposed ocular tissue is ablated or excised through the process of optical breakdown or photodisruption in a very controlled fashion. The process can be gentle enough that the invention makes possible the performance of a number of surgical procedures that in the past could not have been performed at all, such as capsulorhexis, or were performed in a fashion that provided less than an ideal result or excessive trauma to the ocular tissue. Such latter applications include the making of incisions for corneal transplantation, radial and arcuate keratotomy, and intrastromal cavitation. Using the laser inside the eye allows the surgeon to perform glaucoma operations such as trabeculoplasty and iridotomy, cataract techniques such as capsulectomy, capsulorhexis and phacoablation, and vitreoretinal surgery, such as membrane resection. The various procedures are accomplished by controlling energy flux or irradiance, geometric deposition of beam exposure and exposure time.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method for performing a lamellar keratectomy on tissue of a cornea, whereby a partial thickness lamellar disc of tissue is freed from surrounding corneal tissue, said method comprising the steps of:generating a pulsed laser beam by a pulsed laser apparatus, said beam

[ What is claimed is:] [1.]1. A method for performing a lamellar keratectomy on tissue of a cornea, whereby a partial thickness lamellar disc of tissue is freed from surrounding corneal tissue, said method comprising the steps of:generating a pulsed laser beam by a pulsed laser apparatus, said beam having pulses having a duration in a range of about 10 femptoseconds to about 2 picoseconds;said pulses having an energy density at a point of interaction in a material of less than 5 .mu.J/(10 .mu.m).sup.2 ;said pulses having a wavelength transmissive in eye tissue;Wherein the wavelength is in one of a group of ranges consisting of about 400 nm to about 1900 nm, about 2.1 .mu.m to about 2.8 .mu.m, and longer than about 3.1 .mu.m;said beam having up to approximately 100,000 pulses per second;wherein a lasing medium of the pulsed laser apparatus is a broad gain bandwidth laser;wherein the lasing medium of the pulsed laser apparatus uses lasing ions such as titanium, chromium or neodymium (for example, Ti.sub.3 :Al.sub.2 O.sub.3, Cr:LiSrAlF.sub.6, Nd:YLF, or similar lasers);focusing the laser pulses at a selected interaction point in the material;wherein the selected interaction point has a diameter in a range of about 1 .mu.m to about 30 .mu.m;positioning the laser pulses within a selected portion of the material;determining a position of the laser pulses within the material;controlling the diameter of the laser pulses;determining the diameter of the laser pulses;controlling the intensity of the laser pulses;determining the intensity of the laser pulses;controllably blocking the laser pulses from the material;directing the laser beam to a selected start position within the cornea;scanning a laser spot through the corneal tissue in a predetermined manner such that the lamellar disc of the tissue to be removed is outlined and freed from the surrounding corneal tissue by ablating scanned tissue along a path scanned; reby an edge shape of the partial thickness lamellar disc is varied as desired for specific applications by altering the path of the scanning spot as it traverses from within the cornea to finally exit the cornea anteriorly.