Other

Irvision, Inc.

Paul R Yoder, Jr

Carl F Knopp

Hanna J Hoffman

William B Telfair

A surgical technique for removing corneal tissue with scanned infrared radiation is disclosed which utilizes short mid-infrared laser pulses to provide a tissue removal mechanism based on photospallation. Photospallation is a photomechanical ablation mechanism which results from the absorption of incident radiation by the corneal tissue. Since photospallation is a mechanical ablation process, very little heat is generated in the unablated adjacent tissue. The disclosed surgical system includes a scanning beam delivery system which allows uniform irradiation of the treatment region and utilizes low energy outputs to achieve controlled tissue removal. A real-time servo-controlled dynamic eye tracker, based on a multiple-detector arrangement, is also disclosed which senses the motion of the eye and provides signals that are proportional to the errors in the lateral alignment of the eye relative to the axis of the laser beam. Temporal and frequency discrimination are preferably utilized to distinguish the tracking illumination from the ambient illumination and the surgical laser beam.

Method and apparatus for removing corneal tissue with infrared laser

The invention relates to a method and apparatus for uniquely and unambiguously aligning a patient's visual line of sight (LOS) to the optical axis of an ophthalmic instrument such as may be used for laser surgery or diagnostics. By the method of the invention, two alignment targets are imaged at different distances along the optical axis of the ophthalmic instrument. Viewing along the optical axis, a patient moves his or her eye until the two imaged targets are in alignment. When the two imaged targets are viewed in alignment by the patient, the patient's LOS is precisely aligned with the optical axis of the apparatus. By relying on the patient's ability to self-align, this technique ensures that measurements are taken within a reproducible reference frame that is unique to each patient but independent of the type of machine used. The invention is applicable to many instruments and procedures which require precise tracking and positioning of the eye, especially ocular laser surgery devices and various diagnostic instruments employed in tissue imaging or surface topography measurements.

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Norwalk, CT, United States of America

Paul R Yoder, Jr