1、American National Standardfor Ophthalmics Laser Systems for Corneal ReshapingANSI Z80.11-2012ANSIZ80.11-2012ANSIZ80.11-2012Revision ofANSI Z80.11-2007American National Standardfor Ophthalmics Laser Systems forCorneal ReshapingSponsorThe Vision CouncilApproved August 9, 2012American National Standard
2、s Institute, Inc.Approval of an American National Standard requires review by ANSI that therequirements for due process, consensus, and other criteria for approval havebeen met by the standards developer.Consensus is established when, in the judgement of the ANSI Board ofStandards Review, substantia
3、l agreement has been reached by directly andmaterially affected interests. Substantial agreement means much more thana simple majority, but not necessarily unanimity. Consensus requires that allviews and objections be considered, and that a concerted effort be madetowards their resolution.The use of
4、 American National Standards is completely voluntary; theirexistence does not in any respect preclude anyone, whether he has approvedthe standards or not, from manufacturing, marketing, purchasing, or usingproducts, processes, or procedures not conforming to the standards.The American National Stand
5、ards Institute does not develop standards andwill in no circumstances give an interpretation of any American NationalStandard. Moreover, no person shall have the right or authority to issue aninterpretation of an American National Standard in the name of the AmericanNational Standards Institute. Req
6、uests for interpretations should beaddressed to the secretariat or sponsor whose name appears on the titlepage of this standard.CAUTION NOTICE: This American National Standard may be revised orwithdrawn at any time. The procedures of the American National StandardsInstitute require that action be ta
7、ken periodically to reaffirm, revise, orwithdraw this standard. Purchasers of American National Standards mayreceive current information on all standards by calling or writing the AmericanNational Standards Institute.American National StandardPublished byThe Vision Council225 Reinekers Lane, Suite 7
8、00Alexandria, VA 22314Copyright 2012 by The Vision CouncilAll rights reserved.No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of the publisher.Printed in the United States of AmericaDeveloped byThe Accredited C
9、ommittee Z80 for Ophthalmic Standards -The Vision CouncilZ80 Secretariat225 Reinekers Lane, Suite 700Alexandria, VA 22314iContentsPageForeword .iv1 Scope and purpose 12 Normative references. 13 Definitions 34 Mechanical, thermal, and environmental requirements . 54.1 Combination of different devices
10、 54.2 Materials 54.3 Resistance to transport and storage conditions. 55 Safety requirements. 65.1 Protection against contaminants 65.2 Protection against toxins and allergens . 65.3 Photobiological hazards. 65.4 Thermal hazards 65.5 Mechanical hazards. 65.6 Electrical safety 75.7 Radiation safety .
11、75.7.1 Light hazards . 75.8 Gas safety (for gas lasers). 75.9 Safety in use 75.10 System hazard analysis. 86 Optical requirements 86.1 Alignment system. 86.2 Fail safe monitoring 86.3 System calibration 87 System control and performance. 97.1 Software. 98 Clinical evaluation 98.1 Clinical investigat
12、ion plan. 98.2 Surgical procedure. 98.3 Reporting periods and evaluations 98.4 Adverse events 109 Test methods . 109.1 Verification of alignment system accuracy. 109.1.1 Materials 109.1.2 Procedure 10iiPage9.2 Verification of cylinder axis alignment 109.2.1 Materials 109.2.2 Procedure 1110 Accompany
13、ing documents. 1111 Marking 11AnnexesA Spectral weighting function for ultraviolet radiation hazard analysis . 12B Methods for system calibration 14B.1 Plastic plate ablation and measurement 14B1.1 Materials 14B.1.2 Procedure 14B.2 Laminated calibration plate method. 14B.2.1 Materials 14B.2.2 Proced
14、ure 15C Characterization of laser ablation beams and treatment patterns . 16C.1 Ablation characteristics of the beam 16C.2 Mathematical models and simulations. 17C.3 Validation of ablation algorithm software . 17D Guidance on clinical study design of refractive proceduresthat use laser systems for c
15、orneal reshaping 18D.1 General 18D.2 Study objectives. 18D.3 Design of clinical study 19D.4 Study duration 19D.5 Enrollment of subjects . 19D.6 Inclusion and exclusion for subject selection. 20D.6.1 Inclusion criteria. 20D.6.2 Exclusion criteria 20D.7 Examination schedule 21D.8 Evaluations and metho
16、dology 23D.8.1 Visual acuity and manifest refraction . 23D.8.2 Measurement of intraocular pressure 24D.8.3 Subject questionnaire 25D.8.4 Mesopic pupil size . 25D.8.5 Contrast sensitivity. 25D.8.5.1 Grating contrast sensitivity testing . 25iiiPageD.8.6 Low contrast letter acuity testing 26D.8.7 Specu
17、lar microscopy 27D.9 Adverse devise effects / Adverse events . 29E Statistical sample size considerations 30E.1 Statistical symbols and definitions . 30E.2 Calculation of necessary sample sizes 31E.2.1 Sample size based on safety estimates. 31E.2.2 Sample size based on effectiveness estimates usingn
18、oninferiority hypothesis testing. 32E.3 Clinical substudies . 34E.3.1 Sample size for a contrast sensitivity study . 34E.3.2 Sample size for endothelial cell density study 34F Presentation of results of clinical studies . 36F.1 General 36F.2 Accountability of subjects. 36F.3 Refractive stability 38F
19、.4 Safety . 39F.5 Effectiveness 39F.6 Retreatment . 40G Bibliography . 41Tables D.1 Recommended postoperative examination schedule 22E.1 Symbol definitions 30E.2 Normal quantiles to use in equations . 31F.1 Accountability by post-operative visit . 37ivForeword (This foreword is not part of American
20、National Standard ANSI Z80.11-2012.)This American National Standard was developed to address the expressed needs ofthose members of the ophthalmic community who correct the refractive errors of thehuman eye using laser refractive correction procedures, those who manufacture thelasers systems for cor
21、neal reshaping utilized to perform these procedures, and thosewho protect the public interest by ensuring that such systems are made in such away so that they reliably perform their function in a safe and effective manner whenused correctly by skilled operators.It must be realized that correcting th
22、e refractive error of the human eye with laser cor-rective surgery is a medical procedure involving not only a laser system for cornealreshaping but also (1) the assessment of the refractive state of the eye prior to sur-gery, (2) decisions on the best approach to take for treatment that involve not
23、 onlythe judgment of the physician but the desires of the patient, (3) other devices usedduring surgery, (4) the postsurgical care, and (5) the effects of healing, known andunknown. This standard only addresses the laser system for corneal reshaping andmakes no attempt to standardize the procedure i
24、tself.However, in response to a perceived need, informative annexes have been includedin the standard to give guidance on types of clinical testing deemed to be adequate toensure that the entire procedure is safe and effective. It was felt that a service wouldbe performed for those in the field if t
25、his information were to be placed in a publicdocument where it would be readily available for reference.While it is true that the outcome of a laser refractive procedure will not prove accept-able if the laser system for corneal reshaping used to perform it is not adequate forthe task, it cannot be
26、assumed that a laser system is inadequate if outcomes are notacceptable, as this may be the result of deficiencies in other important parts of theoverall medical procedure. Thus, no claim is made such that, if a laser system forcorneal reshaping complies with this standard for the tasks it is design
27、ed to perform,that surgical procedures performed with the laser will have acceptable outcomes.This standard was created by a special working group created by the Z80 Subcom-mittee on Medical Ophthalmic Devices and included experts in the field of laser re-fractive correction from the clinical, manuf
28、acturing and academic areas of theophthalmic community and by experts from the regulatory agency given oversight inthis field in the United States of America.This standard contains seven annexes. Annexes A and B are normative and are con-sidered part of the standard. Annexes C through G are informat
29、ive and are not con-sidered part of this standard.Suggestions for improvement of this standard are welcome. They should be sent tothe Optical Laboratories Association, P.O. Box 2000, Merrifield, VA 22116-2000.This standard was processed and approved for submittal to ANSI by the AccreditedStandards C
30、ommittee on Ophthalmic Optics, Z80. Committee approval of this stan-dard does not necessarily imply that all committee members voted for its approval. Atthe time it approved this standard, the Z80 Committee had the following members:Thomas C. White, M.D., Chairman Quido Cappelli, Vice-Chairman Rober
31、t Rosenberg, O.D., Secretary Jeff Endres, SecretariatvOrganization Represented Name of RepresentativeAdvance Medical Technologies Association.Paul LudingtonRichard Courtney (Alt.)Glenn Davies (Alt.)Bernie Liebler (Alt.)American Academy of OphthalmologyTom White Carl Tubbs (Alt.)Pradeep Ramulu (Alt.)
32、Shannon Curtis (Alt.)American Academy of Optometry .David LoshinAmerican Ceramic SocietyLyle RubinHerbert Hoover (Alt.)American Glaucoma Society.Steven GeddeDouglass Rhee (Alt.)American Optometric Association.Karl CitekRobert Rosenberg (Alt.)William Benjamin (Alt.)William Brown (Alt.)American Societ
33、y of Cataract and Refractive Ophthalmology Stephen KlyceJack Holladay (Alt.)Association for Research in Vision Safety of machinery Basic concepts, general principles for design Part 1: Basic terminology, methodology ISO 12100-2:2003; Safety of machinery Basic concepts, general principles for design
34、Part 2: Technical principles ISO 13849-1:1999, Safety of machinery Safety-related parts of control systems Part 1: General principles for design ISO 13850:1996, Safety of machinery Emergency stop Principles for design ISO 13852:1996, Safety of machinery Safety distances to prevent danger zones being
35、 reached by the upper limbs ISO 13853:1996, Safety of machinery Safety distances to prevent danger zones being reached by the lower limbs ISO 13854:1996, Safety of machinery Minimum gaps to avoid crushing of parts of the human body ISO 14155-1:2003, Clinical investigation of medical devices for huma
36、n subjects Part 1: General requirements ISO 14155-2:2003, Clinical investigation of medical devices for human subjects Part 2: Clinical investigation plans ISO 14971:2000, Medical devices Application risk management to medical devices ISO /FDIS 15004-2 Ophthalmic instruments Fundamental requirements
37、 and test methods Part 2: Light hazard protection SCOEL/SUM/56 final, December 1998. Recommendation from Scientific Committee on Occupational Exposure Limits for Fluorine, Hydrogen Fluoride and Inorganic Fluorides (not uranium hexafluoride). U.S. Code of Federal Regulations Title 21, 1040.10, Laser
38、Products (21 CFR 1040.10) U.S. Code of Federal Regulations Title 21, 1040.11, Special-Purpose Laser Products (21 CFR 1040.11) U.S. Code of Federal Regulations Title 21, 812, Investigation Device Exemptions (21 CFR 812) NOTE: Lasers and laser systems that are sold or imported into the U.S. are requir
39、ed to meet the Federal Performance Standard for Laser Products (21 CFR 1040.10 and 1040.11). At the time of this document revision, the Federal Performance Standard for Laser Products is being amended to harmonize with certain requirements of IEC 60825-1 and IEC 60601-2-22. Guidance has been issued
40、to industry concerning conformance with these IEC standards. ANSI Z80.11-2012 3 3 Definitions For the purpose of this standard, the definitions given below and in ISO 14155-1, ISO 14155-2, ANSI Z136.1, and ANSI Z136.3 apply. Physical Terms 3.1 Ablation zone: The entire corneal region covered by lase
41、r ablation. 3.2 Active eye tracker: A device that monitors eye position relative to a defined reference position, moves the laser beam position to compensate for fixational eye movements, and maintains constant relative positions of the beam and cornea coordinate systems. 3.3 Alignment: Positioning
42、a laser system for corneal reshaping to a desired location in three dimensions with respect to the eye under treatment. 3.4 Beam-positioning module: a motorized device that rotates or translates the exposed portion of the laser beam on the cornea. This may include an active eyetracker that repeatedl
43、y adjusts beam position to compensate for fixational eye movements. The beam-positioning module may be integrated with a beam-shaping module. 3.5 Beam-shaping module: An aperture, mask or other device that allows a predetermined portion of the laser beam to reach the cornea and fashions the ablation
44、 pattern. This may include the capability for manual or motorized adjustment of the size and/or shape of the beam. The beam-shaping module may be integrated with a beam-positioning module. 3.6 Broad beam laser: A laser having a beam for which the size and shape of corneal exposure are controlled by
45、variable apertures, masks, or other mechanisms. 3.7 Centration: The process of positioning the origin of the laser coordinate system by the user to align with the intended point on the cornea. 3.8 Corneal ablation: Removal of tissue from the cornea by a laser beam. 3.9 Critical subsystem: A subsyste
46、m whose malfunction or failure could result in sight-threatening problems or in functionally significant errors in refractive correction. 3.10 Etch rate: The amount of ablated material that is removed by each laser pulse, expressed either as microns/pulse (ablation depth, usually for broad beam lase
47、rs) or microns3/pulse (ablation volume) usually for small beam scanning lasers. 3.11 Etch rate ratio: A comparison of the etch rate in cornea to the etch rate in an inert substrate (usually PMMA), calculated by dividing the substrate etch rate by the corneal etch rate. 3.12 Excimer laser: A pulsed g
48、as laser having output at discrete wavelengths in the ultraviolet region of the spectrum. The excimer (excited dimer) is formed when the appropriate gas mixture is excited, most commonly in a fast high-voltage discharge. ANSI Z80.11-2012 4 3.13 Fluence: Energy per unit area of a laser beam. NOTE: Th
49、is definition is intended solely for use in this standard. 3.14 Beam homogeneity: The spatial uniformity of the laser beam fluence at the treatment plane. 3.15 Laser system for corneal reshaping: An assembly of electrical, mechanical, and optical components, which includes a laser and software algorithms necessary to alter the shape of the cornea through the removal of corneal tissue. 3.16 Optical zone: The corneal region that receives the full intended refractive treatment. 3.17 Passive eye tracker: A device that monitors eye position relative to a defi
