Device and method for correcting astigmatism by laser ablation

• US 6,409,718 B1
• Filed: 02/03/1998
• Issued: 06/25/2002
• Est. Priority Date: 02/03/1998
• Status: Expired due to Fees

• Current Assignee: Lasersight Technologies Inc. (Xianding Weng)
• Original Assignee: Lasersight Technologies Inc. (Xianding Weng)
• Inventors: Tang, Fuqian
• Primary Examiner(s): Dvorak, Linda C. M.
• Assistant Examiner(s): FARAH, AHMED M
• Application Number:
  US09/017,680
• Time in Patent Office: 1,603 Days
• Field of Search: 606/4, 606/5, 606/6, 606/10, 606/11, 606/12, 128/898
• US Class Current: 606/5
• CPC Class Codes: A61F 2009/00872 Cornea
• CPC Class Codes: A61F 2009/00897 Scanning mechanisms or algorithms
• CPC Class Codes: A61F 9/008 using laser
• CPC Class Codes: A61F 9/00802 for photoablation

Abstract

A method for correction of a simple astigmatism of a corneal surface of an eye is provided. The method provides a laser operable to produce a pulsed output laser beam. A scanning mechanism is positioned to operatively receive the pulsed output laser beam of the laser and operable to control the scanning of the pulsed output laser beam over a target surface to be ablated. A computer system is operatively connected to the scanning mechanism for control thereof with the computer system operable to determine a desired configuration of an ablation to be performed on the target surface and to define a boundary associated with the ablation. The computer system is further operable to determine the number of layers required to be ablated to achieve the desired configuration of the ablation and a boundary and a scanning pattern associated with each layer with the computer system and the scanning mechanism operable with one another to ablate the target surface in a series of layers the number of which corresponds to the number determined such that the resultant ablation on the target surface corrects the simple astigmatism.

Claims

1. A method for correcting astigmatism in an eye, said method comprising:

scanning an ablating laser beam in a predetermined pattern across an ablation zone of said eye to form a cylindrical-shaped ablation in a cornea of said eye; and

over ablating a transition region in each end of said cylindrical-shaped ablation.

2. The method for correcting astigmatism in an eye according to claim 1, wherein:

said over ablating forms a trough in each end of said cylindrical-shaped ablation.

3. The method for correcting astigmatism in an eye according to claim 1, wherein:

said over ablating is performed with said scanning said ablating laser beam in said predetermined pattern.

4. The method for correcting astigmatism in an eye according to claim 1, wherein:

said over ablating is performed subsequent to said scanning said ablating laser beam in said predetermined pattern.