US 5,507,741 AGranted

Ophthalmic method for laser surgery of the cornea

OwnerFrancis A. L'Esperance, Jr.inventor

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Abstract

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.

Claims7

Dependent claims

The method of making a precharacterized accessory for use in the path of delivery of an ultraviolet laser beam to perform a curvature-changing sculpture of the anterior surface of a cornea, wherein the accessory comprises a plane-parallel plate of substrate material that is transparent to ultraviolet radiation, and an ablatable membrane layer carried by said plate for expendable use in providing a predetermined ablative sculpture of the optically used central area of the anterior surface of the cornea, said membrane being opaque to ultraviolet radiation and having a central circular area of varying thickness which is a function of radius between central inner and radially outer limits of the circular area, the thickness ranging from zero at one of said limits to maximum at the other of said limits, said membrane being of such maximum thickness within said circular area as to require, for a given intensity of ultraviolet radiation, a predetermined total exposure to achieve total ablation of said maximum thickness, said predetermined total exposure being that which is predetermined to achieve a given maximum stroma-penetration depth for a given sculpturing recurvature of the anterior surface of a cornea exposed to ultraviolet radiation via transmission through said plate;

which method comprises preparing said plate with a uniformly thick membrane layer on one plane surface thereof, the material of said membrane layer being opaque to ultraviolet radiation, and exposing a central area of said layer to selective ultraviolet radiation and attendant ablative photodecomposition in a volumetric removal of membrane material and with full depth penetration at one locality within said central area, and essentially zero depth penetration at another locality within said central area, such that a predetermined thickness profile is established between said localities.

The method of making a precharacterized accessory for use in the path of delivery of an ultraviolet laser beam to perform a curvature-changing sculpture of the anterior surface of a cornea, wherein the accessory comprises a substrate having a flat surface which is a reflector of ultraviolet radiation, and an ablatable membrane layer carried by said surface for expendable use in providing a predetermined ablative sculpture of the optically used central area of the anterior surface of the cornea, said membrane being opaque to ultraviolet radiation and having a central elliptical area of varying thickness which is a function of radius between central inner and radially outer limits of the elliptical area, the thickness ranging from zero at one end of said limits to maximum at the other of said limits, said membrane being of such maximum thickness within said elliptical area as to require, for a given intensity of ultraviolet radiation, a predetermined total exposure to achieve total ablation of said maximum thickness, said predetermined total exposure being that which is predetermined to achieve a given maximum stroma-penetration depth for a given sculpturing recurvature of the anterior surface of a cornea exposed to ultraviolet radiation via transmission via reflection from said surface;

which method comprises preparing said plate with a uniformly thick membrane layer on said flat surface, the material of said membrane layer being opaque to ultraviolet radiation, and at an acute angle of incidence directionally exposing a central area of said layer to selective ultraviolet radiation and attendant ablative photodecomposition in a volumetric removal of membrane material and with full depth penetration at one locality within said central area, and essentially zero depth penetration at another locality within said central area, such that a predetermined thickness profile is established between said localities, and said angle of incidence being such in relation to the major:minor axis relation of said elliptical area as to determine a circular beam section in the reflection from said elliptical area.

Dependencies are inferred from the claim text.

Facts

Application: 07/146,045Filed 20 Jan 1988 · division
Priority: 17 Nov 1983
Granted: 16 Apr 1996
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

B23K 26/08
Working by laser beam, e.g. welding, cutting or boring: devices involving relative movement between laser beam and workpiece
A61F 9/00804
For photoablation: refractive treatments
A61F 9/009
Using laser: auxiliary devices making contact with the eyeball and coupling in laser light, e.g. goniolenses
B23K 26/082
Devices involving relative movement between laser beam and workpiece: scanning systems, i.e. devices involving movement of the laser beam relative…

Family

Serial552,983Parent of this continuation-in-part · filed 17 Nov 1983
Serial742,225Parent of this continuation-in-part · filed 6 Jun 1985
Serial778,801Parent of this continuation-in-part · filed 23 Sep 1985
Serial891,285Parent of this continuation-in-part · filed 31 Jul 1986
Serial74,580Parent of this division · filed 17 Jul 1987
US 4,732,148 AParent of this continuation-in-part
US 5,507,741 AThis patent

From the US filing history. Foreign family members aren’t listed.