LenSx Laser System Operators Manual Rev B Feb 2011

LenSx® Laser System Operator’s Manual

The information contained in this document is the confidential and proprietary property of Alcon LenSx, Inc. (LenSx). Any reproduction, dissemination, or distribution of this document in whole or in part without prior written permission of LenSx is strictly prohibited. While every effort has been made to ensure the accuracy of information provided in this document, please note that the information, figures, illustrations, tables, specifications, and schematics contained herein are subject to change without notice. Please direct all inquiries regarding this manual or for service assistance to Alcon LenSx, Inc., 33 Journey, Aliso Viejo, California 92656. Telephone (949) 360-6010 (in the United States) LenSx and the LenSx logo are registered trademarks of Alcon LenSx Inc. ©2011 LenSx Lasers, Inc. All rights reserved. No portion of this manual may be reproduced or transmitted in any form or by any means without the express prior written consent of LenSx.

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Table of Contents TABLE OF CONTENTS ... III 1

LENSX® LASER SYSTEM ...1 1.1 INDICATIONS FOR USE ... 1 1.2 SUMMARY DESCRIPTION ... 1 1.3 CONTRAINDICATIONS ... 1 1.4 COMPLICATIONS ... 2

2

WARNINGS AND PRECAUTIONS...4 2.1 WARNINGS ... 4 2.1.1 Unauthorized Use of the Laser ... 5 2.1.2 Electrical ... 5 2.1.3 Eye Safety and Nominal Optical Hazard Distance ... 5 2.1.4 Mechanical/Motion ... 6 2.1.5 Combustion/Fire ... 6 2.1.6 Environmental/Chemical ... 6 2.1.7 Sterilization/Biological Contamination ... 7 2.1.8 Emergency Off ... 7 2.2 PRECAUTIONS ... 7 2.2.1 General ... 7 2.2.2 Patient Selection... 7 2.2.3 Surgical Procedure... 7 2.2.4 Power Failure or Emergency Off... 7 2.3 SAFETY FEATURES ... 8 2.3.1 Key Switch ... 8 2.3.2 Laser Enabling ... 8 2.3.3 Laser Emission Indicator ... 8 2.3.4 Protective Housing and Safety Interlock ... 8 2.3.5 Labels... 8 2.3.6 Safety Shutter Monitor ... 9 2.3.7 Footswitch Control ... 9 2.3.8 Remote Interlock Connector ... 9 2.3.9 Emergency OFF Switch ... 9 2.3.10 Laser Cooling System ... 9 2.3.11 Manual Gantry Lift ... 10 2.3.12 Patient Interface RFID ... 10 2.3.13 Console Footbrake ... 10 2.4 DEVICE ELECTRICAL CLASSIFICATION ... 10

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SYSTEM DESCRIPTION ... 11 3.1 INTRODUCTION ... 11 3.2 SYSTEM OVERVIEW ... 11 3.2.1 Femtosecond Laser Engine ... 13 3.2.2 Energy Monitor... 13 3.2.3 Delivery System ... 13 3.2.4 Video Microscope ... 13 3.2.5 Optical Coherence Tomography (OCT) Imaging Device ... 14

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3.2.6 Patient Interface... 14 3.2.7 Surgeon Controls ... 15 3.2.8 System Electronics ... 15 3.2.9 Console Chassis ... 16 3.3 PROCEDURE OVERVIEW... 16 3.3.1 Pre-Operative Steps ... 17 3.3.2 Anterior Capsulotomy ... 17 3.3.3 Phacofragmentation ... 18 3.3.4 Combined Treatments ... 18 3.3.5 Post-Operative Steps ... 18 4

CONTROLS, INDICATORS AND DISPLAYS ... 19 4.1 DISPLAY PANEL & KEYBOARD ... 19 4.2 SURGICAL DISPLAY ... 19 4.2.1 Video Microscope ... 19 4.2.2 Optical Coherence Tomography (OCT) Device ... 19 4.3 DELIVERY SYSTEM PANEL... 20 4.3.1 Joystick ... 20 4.3.2 Delivery System Touch Screen ... 20 4.3.3 Applanation Indicator... 20 4.3.4 Illumination and Microscope Focus ... 20 4.3.5 Fixation Light ... 21 4.4 SYSTEM POWER ... 21 4.4.1 Main Input Switch ... 21 4.4.2 Key Switch ... 21 4.4.3 Emergency off switch ... 21 4.5 FOOTSWITCH ... 21 4.6 SOFTWARE CONTROLS ... 21 4.6.1 System Startup ... 21 4.6.2 Procedure Programming Window ... 22 4.6.3 System Checks ... 22 4.6.4 User Registration ... 22 4.6.5 Shutdown ... 22 4.6.6 About ... 22 4.7 ACCESSORIES & DETACHABLE PARTS ... 23

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SYSTEM REQUIREMENTS ... 24 5.1 ELECTRICAL ... 24 5.2 ENVIRONMENTAL ... 24

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PROCEDURE GUIDE ... 25 6.1 PREPARATION AND TREATMENT PLANNING ... 25 6.2 START UP & PROCEDURE SELECTION ... 25 6.2.1 Programming the Lens Pattern ... 29 6.2.2 Programming the Capsulotomy Pattern ... 30 6.2.3 Programming the Primary Incision Pattern... 30 6.2.4 Programming the Secondary Incision Pattern... 32 6.2.5 Programming the Arcuate Incision Patterns ... 32 6.2.6 Combining Patterns ... 33

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6.2.7 Completing Pattern Selection ... 34 6.3 PREPARING THE PATIENT INTERFACE ... 35 6.4 DOCKING ... 36 6.5 PATTERN POSITIONING... 38 6.5.1 Overview... 38 6.5.2 Video Microscope, OCT Image Guides and Pattern Graphics ... 39 6.5.3 Limbus Centration ... 39 6.5.4 Primary and Secondary Incision Alignment ... 40 6.5.5 Lens Alignment ... 41 6.5.6 Capsule Depth Adjustment ... 42 6.5.7 Lens Depth Adjustment ... 45 6.5.8 Corneal Primary and Secondary Incisions Thickness Adjustment ... 47 6.5.9 Arcuate Incision Thickness Adjustments ... 49 6.6 CONFIRMATION ... 50 6.7 TREATMENT ... 51 6.8 PROCEDURE COMPLETION ... 53 7

CALIBRATION AND ALIGNMENT ... 54 7.1 ENERGY CALIBRATION ... 54 7.2 BEAM STEERING... 54

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SERVICE AND MAINTENANCE ... 55 8.1 TRANSPORT AND STORAGE ... 55

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TROUBLE SHOOTING ... 56

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LABELS... 58 10.1 CONSOLE LABELS ... 58

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SYSTEM SPECIFICATIONS ... 60

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WARRANTY INFORMATION ... 61

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ABBREVIATIONS AND TERMS ... 62 13.1 GENERAL ABBREVIATIONS... 62 13.2 TERMS ... 62 13.3 SYMBOLS ... 62

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NOMINAL OPTICAL HAZARD DISTANCE (NOHD) ... 63

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DECLARATION OF COMPLIANCE ... 66

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1 LenSx® Laser System 1.1 Indications for Use The LenSx® Laser is indicated for use in patients undergoing cataract surgery for removal of the crystalline lens. Intended uses in cataract surgery include anterior capsulotomy, phacofragmentation, and the creation of single plane and multi-plane arc cuts/incisions in the cornea, each of which may be performed either individually or consecutively during the same procedure.

1.2 Summary Description The LenSx® Laser creates incisions through tightly focused femtosecond laser pulses that cut tissue with micron-scale precision. The incision is achieved by contiguously placed microphotodisruptions scanned by a computer-controlled delivery system. The LenSx® Laser System should only be operated by a physician trained in its use. The LenSx® Laser delivery system employs one sterile disposable LenSx® Laser Patient Interface consisting of an applanation lens and suction ring. The Patient Interface is intended for singleuse, only. Refer to the Instruction for Use supplied with the LenSx® Laser Patient Interface for preparation and application instructions for the patient interface. The physician should base patient selection criteria on professional experience, published literature, and educational courses. Adult patients should be scheduled to undergo cataract extraction.

1.3 Contraindications Contraindications for the anterior capsulotomy, phacofragmentation of the lens using the LenSx® Laser include the following: • • • • • • •

Corneal disease that precludes applanation of the cornea or transmission of laser light at 1030 nm wavelength Descemetocele with impending corneal rupture Corneal opacity that would interfere with the laser beam Presence of blood or other material in the anterior chamber Hypotony, glaucoma, or the presence of a corneal implant Poorly dilating pupil, such that the iris is not peripheral to the intended diameter for the capsulotomy Conditions which would cause inadequate clearance between the intended capsulotomy depth and the endothelium (applicable to capsulotomy only)

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• • • •

Residual, recurrent, active ocular or eyelid disease, including any corneal abnormality (for example, recurrent corneal erosion, severe basement membrane disease) A history of lens or zonular instability Any contraindications to cataract or keratoplasty surgery This device is not intended for use in pediatric surgery.

Contraindications for corneal incisions using the LenSx® Laser include the following: • • • • • •

Previous corneal incisions that might provide a potential space into which the gas produced by the procedure can escape Corneal thickness requirements that are beyond the range of the system Corneal opacity that would interfere with the laser beam Hypotony, glaucoma, or the presence of a corneal implant Residual, recurrent, active ocular or eyelid disease, including any corneal abnormality (for example, recurrent corneal erosion, severe basement membrane disease) This device is not intended for use in pediatric surgery.

Potential contraindications are not limited to those included in this list.

1.4 Complications Possible complications resulting from anterior capsulotomy, phacofragmentation, or creation of a partial thickness or full-thickness cut or incision include: • • • • • • • • •

Capsulotomy, phacofragmentation, or cut or incision decentration Interrupted capsulotomy, fragmentation, or corneal incision procedure Capsular tear Corneal abrasion or defect Pain Infection Bleeding Damage to intraocular structures Anterior chamber fluid leakage, anterior chamber collapse

In the case of an incomplete or interrupted capsulotomy, the procedure may be immediately repeated with a slightly larger diameter to complete the capsulotomy. In the case of an incomplete or interrupted fragmentation or partial thickness or full-thickness arc cut/incision, the procedure can be repeated at a slightly different position using the centration feature.

Cataract removal should be performed after anterior capsulotomy with the LenSx® Laser. In the initial clinical protocol using the LenSx®, cataract removal was begun within 30 minutes after the laser procedure. In previous studies using the Nd:YAG laser to perform anterior

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capsulotomy, anterior chamber inflammation and elevated intraocular pressure were noted when cataract surgery was delayed from one hour to up to one day following laser treatment.1, 2 The Nd:YAG laser requires 100 times more energy per pulse than femtosecond lasers to induce photodisruption. Potential complications are not limited to those included in this list. These complications may be surgically or medically managed using currently accepted techniques for cataract or keratoplasty procedures.

1

Woodward PM. Anterior Capsulotomy using a neodymium YAG laser. Ann Ophthalmol: 16:534-9, 1984. 2 Szweda E. Preoperative anterior capsulotomy using YAG laser in cataract extraction by the envelop method. Klin Oczna: 93: 334-6, 1991.

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2 Warnings and Precautions 2.1 Warnings The LenSx® Laser is indicated for use in patients undergoing cataract surgery for removal of the crystalline lens. Intended uses in cataract surgery include anterior capsulotomy, phacofragmentation, and the creation of single plane and multi-plane arc cuts/incisions in the cornea, each of which may be performed either individually or consecutively during the same procedure. United States Federal Law restricts this device to sale and use by or on the order of a physician or licensed eye care practitioner. United States Federal Law restricts the use of this device to practitioners who have been trained in the operation of this device. The performance of surgical procedures, operation of controls, or any other adjustments other than those specified herein may result in hazardous conditions for both patients and personnel. While the risk of fire is extremely low, the LenSx® Laser should not be operated in the presence of flammable anesthetics, volatile substances, or oxygen flow lines. WARNING: Do not use cell phones or pagers of any kind in the same room as the LenSx® Laser. The LenSx® Laser complies with 47 CRF 15 Federal Communication Commission Rules for radio frequency devices. Changes or modifications not expressly approved by Alcon LenSx Inc. can void the operator’s authority to operate this radio frequency device. Only trained LenSx representatives should perform unpacking, installation, and servicing of the LenSx® Laser. Covers are not to be removed by anyone other than LenSx personnel. Accidental contact with the high voltage electrical circuits in the interior of the LenSx® Laser console may result in serious injury or death. Ocular exposure to collimated beams contained in the console interior can produce retinal damage. Surgical lasers must meet requirements established by the Food and Drug Administration (FDA) Center for Devices and Radiological Health and international standards and regulations for surgical lasers. Specific controls are required that prevent accidental exposure of laser energy to the eye and skin from both direct and reflected laser beams. In addition, precautions must be taken in the surgical area to prevent fire and electrical hazards. Improper use of the LenSx® Laser may result in patient corneal trauma, infection, complications, or mechanical trauma to either patient or personnel. All warnings, labeling and instructions must be observed.

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2.1.1 Unauthorized Use of the Laser When not in use, the master key should be removed from the LenSx® Laser and kept in a secure location to prevent use of the laser by unauthorized personnel. Once the console is switched ON, password protection is required to access any laser functions.

2.1.2 Electrical High voltage electrical circuits are accessible if the console panels are removed. Only trained LenSx service representatives should attempt to open the console panels. Serious injury or death may occur while contacting electrical circuits in the unit interior. Tools are required to remove the console panels. Panels should not be removed by anyone other than LenSx service personnel. While the LenSx® Laser requires 120VAC, 60Hz, 10A electrical service, the system is configurable for the following input voltages: 100VAC/12A, 120V/10A, 220-240V/7A, and 50/60Hz. The line voltage should be tested prior to laser installation and must be within specified limits for proper operation of the unit. An interlock connection allows the use of safety interlock switches on the operating suite doors that automatically place the laser in STANDBY mode when the suite door(s) is opened. The area around the LenSx® Laser and the footswitch should be kept dry. The laser should not be operated if there is any leakage of water from the console. A LenSx service representative should be contacted immediately. If the unit power cord is frayed or otherwise damaged, do not use unit until cord has been replaced. A tripping hazard exists if the AC power cord is not protected from foot traffic. Care must be taken to avoid accidental unplugging of the LenSx® Laser during treatment.

2.1.3 Eye Safety and Nominal Optical Hazard Distance The NOHD is defined according to American National Standards Institute Z136.1-2007, “American National Standard for Safe Use of Lasers”. The NOHD is computed in terms of the Maximum Permissible Exposure (MPE) allowed onto the eye. For the LenSx® Laser the NOHD calculated using this standard is short due to the small pulse energies emitted by the laser. The most conservative NOHD for a direct beam exposure from the LenSx® Laser is 106 cm (See Appendix 2). This means that only the patient operative eye will be exposed to laser radiation exceeding the MPE. The practical consequence is that operators and support personnel are not at risk of optical radiation during normal and routine operation of the laser. Any service operation requiring the removal of any covers or shields on the console will require eyewear of OD ≥ 5 at a wavelength

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of 1030 nm. Only authorized LenSx service representatives should attempt to remove console covers or to service the LenSx® Laser. Standard laser safety protocol requires that a warning sign be placed on the door of the room when the laser is in use, to warn personnel of laser usage in progress before they enter the controlled area. The door should be closed during the operation of the laser. Removing the console covers increases the risk of eye injury. Only trained LenSx service representatives should remove the console covers or attempt servicing of the LenSx® Laser. An interlock connection allows the use of safety interlock switches on the operating suite door(s) that automatically disables laser emission when the surgical suite door(s) is opened. The Patient Interface disposable cannot be reused or re-sterilized; the LenSx® Laser will not be operable with a previously used Patient Interface.

2.1.4 Mechanical/Motion The LenSx® Laser console is stable and mobile within an operating room. No significant tipping or rolling hazard exists once the console is placed in the locked position for surgery. Only trained personnel should move the console. If the console must be moved for any reason, a LenSx service representative should be contacted. When installed, a footbrake at the back of the unit prevents the console from rolling. The footbrake must be engaged during treatment. Removing the console covers is a potential mechanical hazard. This operation should be performed only by trained LenSx service representatives. After docking is complete, the user should not move the delivery system until patient is disengaged from the system.

2.1.5 Combustion/Fire Although the possibility of combustion is remote, flammable anesthetics should not be used with the LenSx® Laser. Oxygen lines and flammable materials should be kept clear of the immediate area surrounding the laser aperture.

2.1.6 Environmental/Chemical No hazardous gases or chemicals are used in the LenSx® Laser.

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2.1.7 Sterilization/Biological Contamination The LenSx® Laser is used with the LenSx® Laser Patient Interface. This sterile assembly cannot be reused and should be disposed of as medical waste.

2.1.8 Emergency Off In the event of an emergency, the LenSx® Laser should be immediately shut down by pressing the red emergency OFF button located at top center on the front panel. If the LenSx® Laser is shut down (by pressing the Emergency Off button or by a loss of power), the patient may be removed from under the delivery system by lowering the bed or by actuating the manual gantry lift located at the base of the delivery system gantry.

2.2 Precautions 2.2.1 General The Patient Interface will increase intraocular pressure during the procedure. Care must be taken to minimize applanation times. Incomplete applanation may result in non-uniform or incomplete incisions.

2.2.2 Patient Selection •

• •

Patients must be able to lie flat and motionless in a supine position. Patient must be able to understand and give an informed consent. Patients must be able to tolerate local or topical anesthesia. Patients with elevated IOP should use topical steroids only under close medical supervision.

2.2.3 Surgical Procedure Full thickness cuts or incisions should be performed with instruments and supplies on standby to seal the eye in case of anterior chamber collapse or fluid leakage. Surgical treatment should be halted if the OCT image is poor or disrupted. During use, the user should not move, shake or bump the delivery system after docking is completed until patient is disengaged from the system.

2.2.4 Power Failure or Emergency Off In the event of power failure or initiation of the Emergency Off button, remove the patient interface tube from the vacuum port to release the eye from suction. Grasp the delivery system objective and raise it 1 to 2 inches to safely remove the patient from the surgical field.

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The Manual Gantry Lift, located at the base of the gantry, allows the user to lift the unpowered gantry if additional patient clearance is needed. Alternatively, the patient bed may be lowered to provide clearance.

2.3 Safety Features The LenSx® Laser complies with all performance standards specified by the Center for Devices and Radiological Health of the U.S. Food and Drug Administration and international standards for surgical lasers, and includes the following safety features:

2.3.1 Key Switch The laser console can be turned ON only with the appropriate master key that controls the master switch. The key ON switch is located at the bottom center of the front panel of the laser console. When the master key is turned ON, power is available to the instrument. The master key cannot be removed when switched to the ON position, and the laser will operate only with the key in place.

2.3.2 Laser Enabling When the key switch turns on the system power, a Login window appears. Login prevents unauthorized use. Following successful login, laser operation is disabled while the microprocessor checks for basic fault conditions and the system stabilizes. After this period, the Procedure window will appear on the Display Panel.

2.3.3 Laser Emission Indicator Laser emission is indicated by a red LASER EMISSION indicator on the Display Panel.

2.3.4 Protective Housing and Safety Interlock The LenSx® Laser has a protective housing that prevents unintentional access to laser radiation. This housing should be opened only by a qualified LenSx representative.

2.3.5 Labels Appropriate warning labels are mounted in specified locations on the laser system to indicate conditions under which the user could be subjected to laser radiation (See Section 10).

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2.3.6 Safety Shutter Monitor Dual safety shutters, closed unless the system is in the TREATMENT mode, prevent laser radiation from exiting the instrument. Shutter status is continuously monitored. Should a malfunction occur (i.e. a safety shutter opens in the absence of a footswitch press) the laser console is disabled and a messaged is displayed. The LenSx® Laser cannot be re-enabled until the fault condition has been cleared.

2.3.7 Footswitch Control The footswitch is housed in an industrial grade enclosure and cannot be activated unless the LenSx® Laser has completed all steps in preparation for laser incision. Position switches in the housing are arranged such that the footswitch pedal position is redundantly monitored.

2.3.8 Remote Interlock Connector The system is equipped with an outlet for the interlocking of room doors. A message on the system display appears when the remote interlock is not connected properly or has been broken by some action, such as the opening of an operating room door. LenSx representatives should be contacted for assistance in establishing a remote interlock.

2.3.9 Emergency OFF Switch The emergency OFF switch is a red button located on the front panel of the console. When pressed, the emergency off switch shuts off the main system power. This control should be used only in the event of an emergency. If the LenSx® Laser is shut down (by pressing the Emergency Off button or by a loss of power), the patient may be removed from under the delivery system by lowering the bed or by actuating the manual gantry lift located at the base of the delivery system gantry. To restart the system after the emergency off switch is actuated, twist the red emergency off button until it disengages; turn the key switch to the OFF position and return it to the ON position. The system will then reboot normally. Follow the System Startup instruction in section 4.6.1.

2.3.10

Laser Cooling System

The LenSx® Laser uses an internal re-circulating cooling system whose fluid levels are checked during preventive maintenance. Coolant levels are automatically monitored by the system and if a low coolant error occurs, a message is displayed. An authorized LenSx service representative should be called if a coolant error occurs.

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2.3.11

Manual Gantry Lift

The manual gantry lift allows the user to raise the gantry mechanism up using a manual screw. The manual lift knob is found at the base of the gantry a few inches above the floor. When the system is unpowered, the knob is free to turn.

2.3.12

Patient Interface RFID

Each LenSx® Laser Patient Interface is instrumented with an RFID tag. The RFID tag authenticates the Patient Interface for use with the LenSx® Laser and prevents reuse or use by unauthorized patient interfaces.

2.3.13

Console Footbrake

When the laser system is installed, a footbrake at the back of the unit prevents the console from rolling. The footbrake must be engaged during treatment.

2.4 Device Electrical Classification • • •

Protection against electric shock: Protection against electric shock Patient Applied Part: Mode of Operation:

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Class I Equipment Type BF Continuous Operation

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3 System Description 3.1 Introduction The LenSx® Laser System uses focused femtosecond laser pulses to create incisions and separates tissue in the lens capsule, crystalline lens and cornea. Individual photodisruption locations are controlled by repeatedly repositioning the laser focus. The light pulse is focused into a sufficiently small spot in order to achieve photodisruption of the tissue inside the focus. A tiny volume of tissue, a few microns in diameter, is photodisrupted at the laser focus. The surgical effect is produced by scanning thousands of individual pulses per second to produce a continuous incision or tissue separation. The location of the tissue photodisruption is controlled by moving the focus of the laser beam to the desired surgical target location. A computer-controlled scanning system directs the laser beam throughout a three-dimensional pattern to produce an incision. The laser pulses are delivered through a sterile, disposable applanation lens and suction ring assembly that contacts the cornea and fixes the eye with respect to the delivery system.

3.2 System Overview The LenSx® Laser is a CDRH CFR 1040 class 3B and a IEC 60825-1 class 3R laser system for ocular surgery consisting of the following components: • • • • •

a laser source to produce femtosecond laser pulses; an aiming device to localize specific targets in the eye; an optical delivery system to precisely deliver laser pulses to desired targets in the eye; computer controllers to perform clinical procedures; a disposable patient interface optically coupling the eye to the optical delivery system in order to prevent eye movement.

The LenSx® Laser is a stand-alone unit requiring no external water or gas connections. The device console houses the laser source, power supplies, control electronics, cooling system, beam delivery device, optical coherence tomography (OCT) device, video microscope and computers. The console itself is designed for use in a medical setting meeting US and international standards (ETL) for electromagnetic emissions for medical devices. The laser beam and all collateral radiation are completely enclosed inside the console. The Key ON switch and Emergency Off button are located on the front panel of the console where they are easily identified and accessed. The LenSx® Laser System is shown in Figure 3-1.

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Figure 3-1: LenSx® Laser System An all-solid-state laser source produces a kHz pulse train of femtosecond pulses. The amplified pulse train is routed through a beam monitoring assembly comprised of energy monitors, an energy attenuator and the primary safety shutter. An optical articulated arm directs laser light to the delivery system where a second shutter controls the beam. Computer controlled scanning mirrors direct the light through a beam expander and through a focusing objective onto a spot at pre-determined depth within the eye. An optical coherence tomography (OCT) imaging device and a video camera microscope (VM) are used to localize specific targets and to view the patient’s eye. The LenSx® Laser System uses a sterile disposable patient interface that attaches to the distal end of the focusing objective. The patient interface is lowered to the eye until it contacts the eye. Suction then holds the eye in position. Once parameters for the desired procedure are selected using the software interface, the procedure is initiated by pressing the footswitch. Although the system computer controls the laser operation during the incision and laser pulse positioning, the procedure may be stopped at any time by releasing the footswitch. The following sections briefly describe the major components outlined in Figure 3-1.

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3.2.1 Femtosecond Laser Engine Consistent with well-established femtosecond laser principles, the laser engine uses a conventional amplified laser design in which pulses with sufficient bandwidth are generated by an oscillator, amplified to higher energies, and finally compressed in time to femtosecond pulse duration. The oscillator produces femtosecond laser pulses of nanojoule energy. These pulses are temporally expanded by a pulse “stretcher” and are then directed into a diode-pumped regenerative amplifier where the pulse energy is increased as the pulse completes a number of round-trips within the amplifier cavity. When the pulse energy reaches microjoule energies, the pulse is switched out of the amplifier cavity. Amplified pulses are routed to a grating compressor to temporally compress the pulses back to the femtosecond range.

3.2.2 Energy Monitor The beam of compressed pulses from the laser then enters the energy monitoring assembly. A computer controlled energy attenuator adjusts the beam energy to programmed levels and energy monitors verify the beam energy. A primary shutter, that is normally closed when not energized, controls the release of the beam from the energy monitor. Electronic hardware closes the shutters in the event that the energy monitors report an unexpected or out-oftolerance pulse.

3.2.3 Delivery System The delivery system focuses the beam of laser pulses onto a focus spot at a programmed location. Upon exiting the energy monitor, the beam enters an articulated arm that terminates at the delivery system. A second shutter at the delivery system controls the laser beam through the delivery system. The beam then enters a set of computer controlled scanning mirrors that scan the beam into a beam-expanding telescope. Each scanned position of the beam corresponds to an X, Y location in the focal plane of the focusing objective. The Z position of the focused laser spot is computer controlled by optical zoom lenses located in the beam expander. The entire delivery system is mounted on a motorized gantry attached to the system console to allow the user to position the delivery system. The alignment of the beam through the delivery system is automatically verified before each procedure. Users can also request that an alignment check be performed using the Beam Steering selection in the System Checks menu.

3.2.4 Video Microscope The delivery system includes a Surgical Display that provides a video microscope view of the surgical field at all times. Illumination of the field is controlled with an internal electronic controller and a touch screen interface mounted on the console. The video image provides the

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surgeon with surgical details such as the position of the pupil. The surgeon observes the video image to adjust and verify the position of the surgical patterns during programming and performance of the procedure.

3.2.5 Optical Coherence Tomography (OCT) Imaging Device The Surgical Display also includes an optical coherence tomography (OCT) based imaging device that assists in localizing specific target locations. The OCT consists of a low power visible wavelength light source that is scanned throughout the transparent structures of the anterior chamber of the eye. Light scattered from ocular structures and surfaces within the eye is analyzed to produce cross sectional images of the eye’s anterior segment. Various sectioned images may be produced, including a wide field line scan of the anterior chamber, magnified cross sections of the cornea at the points of planned incisions, and circle and line scans of the lens and capsule. The surgeon uses these OCT images to adjust and verify the position and orientation of the selected surgical patterns.

3.2.6 Patient Interface The LenSx® Laser uses a sterile, disposable Patient Interface (Figure 3-2). The Patient Interface is comprised of an applanation lens, suction ring and tubing. The suction ring and curved applanation lens are integrated into a single piece and mounted on the laser delivery system. The Patient Interface is mounted onto the distal end of the laser focusing objective and serves as a sterile barrier between the patient and the laser. Tubing is connected to a filter and to a vacuum port on the laser system. The Patient Interface also contains an integrated passive Radio Frequency Identification (RFID) device. The RFID is sensed by a reader located inside the LenSx® Laser System console. The lens is lowered onto the patient’s eye until the cornea is applanated; suction is then activated.

Figure 3-2: LenSx® Laser Patient Interface – (1) Interface Cone and gripper; (2) tubing; (3) filter and RFID; (4) vacuum port.

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Using the gantry joystick and visualization via the video microscope, the curved applanation cone (that is attached to the laser delivery system) is lowered to make contact onto the eye. The applanation force indicator is in the yellow or green zone when adequate applanation force is achieved, allowing the surgeon to apply suction via touch screen activation of an internal pump to fixate the eye. Graphical overlay software tools (reference to a live video image of the eye on the graphical user interface) are used to adjust the centration of the programmed cutting pattern to the desired position. When the procedure is completed, suction is released and the focusing objective is lifted, removing the applanation lens from the surface of the eye. The applanation lens and tubing are then disposed.

3.2.7 Surgeon Controls The surgeon controls the LenSx® Laser primarily by a console interface comprised of two display monitors (the Display Panel and Surgical Display), a keyboard, a touch pad and a trackball. Parameters for photodisruption pattern and system information are entered at the console interface. The system software allows the surgeon to select pattern parameters and to prepare the laser for treatment. Directly next to the console interface are the master key switch, which is used to start the system, and the emergency OFF switch. Other important surgeon controls include an X, Y, & Z joystick that actuate the motorized gantry supporting the delivery system. The joystick is used to align the delivery system over the patient and to make contact with the patient eye. A small touch screen is used to control the utilities associated with the delivery system, including the illumination controls, docking controls and video microscope focusing controls. A footswitch allows the surgeon to start and stop laser treatment. The surgeon initiates laser treatment by first navigating the software interface until the system is READY and starts the treatment by pressing the footswitch. The surgeon can interrupt the procedure at any time by releasing the footswitch. After interruption, the surgeon restarts the procedure by pressing and holding down the footswitch again. The laser will continue the treatment until the programmed pattern is complete.

3.2.8 System Electronics The LenSx® Laser console can be configured for 100V, 120V, 220-240V, 50/60Hz operation. AC to DC converters supply system electronics, laser diodes and thermoelectric coolers with low voltage DC current. The maximum power draw is less than 1.2 kW. Electronic sensors monitor the position of the patient interface when mounted onto the delivery system. If the applanation lens is unlocked or out of position, hardware sends an error 80-0001

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