Patent ID: 8057463
Filing Date: 2011-11-15
Classification: A61F,G02B

Abstract:
1. A method for scanning, with a laser scanner system having a controller and a laser scanner, a focal point of a laser along a desired scan pattern so as to incise an optical tissue of an eye of a patient in an ophthalmic surgical procedure, the method comprising: receiving, with the controller, an input of the desired scan pattern and a scan rate or spot separation input by a user into the controller; calculating with the controller a directed scan pattern from the desired scan pattern and the scan rate or spot separation input using an error correction factor, wherein the error correction factor characterizes focal positioning errors, the errors associated with mechanical lag of the laser scanner, wherein the errors are characteristically introduced by the laser scanner and vary with the scan rate or spot separation, and wherein the error correction factor is determined by scanning a plurality of scans of a given scan pattern at differing scan rates or differing spot separations, measuring corresponding focal point positioning errors in each of the plurality of scans of the given scan pattern, and performing a linear regression to determine the error correction factor as a function of the scan rate or spot separation, respectively, wherein the error correction factor ‘ε transmitting movement control signals to the laser scanner to scan a focal point of a laser beam along a first axis and along a second axis transverse to the first axis per the directed scan pattern, wherein the control signals are transmitted by the controller to the laser scanner; and scanning the laser scanner in response to the control signals such that the focal point actually scans in a targeted scan pattern, the targeted scan pattern being different from the directed scan pattern such that the system mitigates distortion of the scan pattern geometry associated with the positioning errors in the first axis before the laser beam is directed to the tissue and wherein the targeted scan pattern more closely approximates the desired scan pattern than does the directed scan pattern.