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Exposing the LASIK Scam • View topic - Keratome and Replacement Keratome Blades Guidance Document
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Keratome and Replacement Keratome Blades Guidance Document
Post subject: Keratome and Replacement Keratome Blades Guidance Document
Posted: Tue Sep 26, 2006 12:49 pm
http://www.fda.gov/cdrh/ode/guidance/1604.html
Keratome and Replacement Keratome Blades Premarket Notification [510(k)] Submissions
Document issued on: September 18, 2006
For questions regarding this document, contact Everette T. Beers at 301-594-2018 ext. 136 or by email at everette.beers@fda.hhs.gov.
Diagnostics and Surgical Devices Branch
Division of Ophthalmic, Ear, Nose and Throat Devices
Written comments and suggestions may be submitted at any time for Agency consideration to the Division of Management, Food and Drug Administration, 5630 Fishers Lane, Room 1061, (HFA-305), Rockville, MD, 20852. Alternatively, electronic comments may be submitted to http://www.fda.gov/dockets/ecomments. When submitting comments, please refer to the exact title of this guidance document. Comments may not be acted upon by the Agency until the document is next revised or updated.
Additional copies are available from the Internet at: http://www.fda.gov/cdrh/ode/guidance/ specifc address.html. You may also send an e-mail request to dsmica@fda.hhs.gov to receive an electronic copy of the guidance or send a fax request to 240-276-3151 to receive a hard copy. Please use the document number (1604) to identify the guidance you are requesting.
1. INTRODUCTION.................................................................................................................1
The Least Burdensome Approach............................................................................................1
2. BACKGROUND...................................................................................................................2
3. THE CONTENT AND FORMAT OF AN ABBREVIATED 510(K) SUBMISSION....2
4. SCOPE..................................................................................................................................5
5. DEVICE DESCRIPTION....................................................................................................5
6. RISKS TO HEALTH............................................................................................................7
7. PRECLINICAL ASSESSMENT.........................................................................................7
8. SOFTWARE VALIDATION...............................................................................................9
9. ELECTRICAL SAFETY AND ELECTROMAGNETIC COMPATIBILITY...............9
10. MATERIAL CHARACTERIZATION AND BIOCOMPATIBILITY.........................10
11. STERILIZATION...............................................................................................................11
12. LABELING........................................................................................................................11
APPENDIX ? INFORMATION FOR REPLACEMENT KERATOME BLADES...............13
FDA has developed this guidance document to assist industry in preparing premarket notification submissions for keratomes and replacement keratome blades. The device is intended to shave tissue from sections of the cornea for a lamellar (partial thickness) transplant. Keratomes, originally used during cornea transplant surgery, are now widely used during the laser refractive surgical procedure known as laser-assisted in situ keratomileusis (LASIK).
The issues identified in this guidance document represent those that we believe need to be addressed before your device can be marketed. In developing the guidance, we carefully considered the relevant statutory criteria for Agency decision-making. We also considered the burden that may be incurred in your attempt to follow the guidance and address the issues we have identified. We believe that we have considered the least burdensome approach to resolving the issues presented in the guidance document. If, however, you believe that there is a less burdensome way to address the issues, you should follow the procedures outlined in the "A Suggested Approach to Resolving Least Burdensome Issues" document. It is available on our Center web page at: http://www.fda.gov/cdrh/modact/leastburdensome.html.
A manufacturer who intends to market a device of this generic type should conform to the general controls of the Federal Food, Drug, and Cosmetic Act (the act), including the premarket notification requirements described in 21 CFR 807 Subpart E, and obtain a substantial equivalence determination from FDA prior to marketing the device. (See also 21 CFR 807.81 and 807.87). This guidance document identifies the classification regulation and product codes for keratomes and replacement keratome blades (refer to Section 4. Scope). In addition, other sections of this guidance document provide additional information to manufacturers on addressing risks related to these devices in premarket notifications (510(k)s).
This document supplements other FDA documents regarding the specific content requirements of a premarket notification submission. You should also refer to 21 CFR 807.87 and "How to Prepare a 510(k) Submission" on FDA Device Advice at http://www.fda.gov/cdrh/devadvice/314.html.
Under ?The New 510(k) Paradigm - Alternate Approaches to Demonstrating Substantial Equivalence in Premarket Notifications,? http://www.fda.gov/cdrh/ode/parad510.html, a manufacturer may submit a Traditional 510(k) or has the option of submitting either an Abbreviated 510(k) or a Special 510(k). FDA believes an Abbreviated 510(k) provides the least burdensome means of demonstrating substantial equivalence for a new device, particularly once FDA has issued a guidance document addressing that device. Manufacturers considering certain modifications to their own cleared devices may lessen the regulatory burden by submitting a Special 510(k).
An Abbreviated 510(k) submission must include the required elements identified in 21 CFR 807.87, including the proposed labeling for the device sufficient to describe the device, its intended use, and the directions for its use. In an Abbreviated 510(k), FDA may consider the contents of a summary report to be appropriate supporting data within the meaning of 21 CFR 807.87(f) or (g); therefore, we recommend that you include a summary report. The report should describe how this guidance document was used during the device development and testing and should briefly describe the methods or tests used and a summary of the test data or description of the acceptance criteria applied to address the risks identified in this document, as well as any additional risks specific to your device. This section suggests information to fulfill some of the requirements of section 807.87 as well as some other items that we recommend you include in an Abbreviated 510(k).
The coversheet should prominently identify the submission as an Abbreviated 510(k) and cite the title of this guidance document.
Proposed labeling should be sufficient to describe the device, its intended use, and the directions for its use. (Please refer to Section 14. Labeling for specific information that should be included in the labeling for devices of the types covered by this guidance document.)
We recommend that the summary report contain:
We recommend that you describe the performance specifications and, when appropriate, include detailed, labeled drawings of the device. Please refer to Section 5. Device Description for specific information that we recommend you include in the device description for devices of the types covered by this guidance document. You should also submit an ?indications for use? enclosure.1
We recommend that you identify the risk analysis method(s) you used to assess the risk profile, in general, as well as the specific device?s design and the results of this analysis. (Please refer to Section 6. Risks to Health and Section 7. Hazards Assessment for the risks to health generally associated with the use of this device that FDA has identified.)
We recommend that you discuss the device characteristics that address the risks identified in this guidance document, as well as any additional risks identified in your risk analysis.
We recommend that you include a brief description of the test method(s) you have used or intend to use to address each performance aspect identified in Sections 5 - 13 of this guidance document. If you follow a suggested test method, you may cite the method rather than describing it. If you modify a suggested test method, you may cite the method
1 Refer to http://www.fda.gov/cdrh/ode/indicate.html for the recommended format.
but should provide sufficient information to explain the nature of and reason for the modification. For each test, you may either (1) briefly present the data resulting from the test in clear and concise form, such as a table, or (2) describe the acceptance criteria that you will apply to your test results.2 (See also 21 CFR 820.30, Subpart C - Design Controls for the Quality System Regulation.)
? statement that testing will be conducted and meet specified acceptance criteria before the device is marketed; or
? declaration of conformity to the standard.3
Because a declaration of conformity is based on results from testing, we believe you cannot properly submit a declaration of conformity until you have completed the testing the standard describes. For more information, please refer to section 514(c)(1)(B) of the act and the FDA guidance, Use of Standards in Substantial Equivalence Determinations, http://www.fda.gov/cdrh/ode/guidance/1131.html.
If it is not clear how you have addressed the risks identified by FDA or additional risks identified through your risk analysis, we may request additional information about aspects of the device?s performance characteristics. We may also request additional information if we need it to assess the adequacy of your acceptance criteria. (Under 21 CFR 807.87(l), we may request any additional information that is necessary to reach a determination regarding substantial equivalence.)
As an alternative to submitting an Abbreviated 510(k), you can submit a Traditional 510(k) that provides all of the information and data required under 21 CFR 807.87 and described in this guidance. A Traditional 510(k) should include all of your methods, data, acceptance criteria, and conclusions. Manufacturers considering certain modifications to their own cleared devices should consider submitting Special 510(k)s.
2 If FDA makes a substantial equivalence determination based on acceptance criteria, the subject device should be tested and shown to meet these acceptance criteria before being introduced into interstate commerce. If the finished device does not meet the acceptance criteria and, thus, differs from the device described in the cleared 510(k), FDA recommends that submitters apply the same criteria used to assess modifications to legally marketed devices (21 CFR 807.81(a)(3)) to determine whether marketing of the finished device requires clearance of a new 510(k).
3 See Required Elements for a Declaration of Conformity to a Recognized Standard (Screening Checklist for All Premarket Notification [510(K)] Submissions), http://www.fda.gov/cdrh/ode/reqrecstand.html.
The scope of this document is limited to the device described below, 21 CFR 886.4370, class I, product codes HNO (Keratome, AC-Powered), HMY (Keratome, Battery-Powered), and NKY (Blade, Keratome, Reprocessed).
? 21 CFR 886.4370 Keratome.
A keratome is an AC-powered or battery powered device intended to shave tissue from sections of the cornea for a lamellar (partial thickness) transplant.
Water jet keratomes (product code MYD) classified under 886.4370 are not within the scope of this guidance. Laser keratome devices classified under 21 CFR 878.4810, Laser Surgical Instrument for Use in General and Plastic Surgery and in Dermatology also are not within the scope of this guidance. In addition, reprocessed single use devices?such as reprocessed keratome blades?have additional requirements for validation of the cleaning and sterilization process that are not discussed in this guidance.4
5. Device Description
We recommend that you identify your device by the regulation and product code described in Section 4. We recommend that you provide a description, as discussed below, of the technical specifications, principles of operation, and of any keratome blades used with your device.
A. Technical Specifications
1. We recommend you list, with references to drawings or photographs, all parts (and associated specifications) necessary to carry out the device?s intended use, including, but not limited to:
? console, handpiece, motors, keratome head, keratome blades, tubing, fixation ring, eye attachment mechanism;
? any interchangeable components used to change depth or diameter of the flap or width of the hinge (e.g., depth plates); and
? any items that can be ordered as optional add-ons.
2. We recommend you identify the material composition of device components and include references to your drawings or photographs.
4 See Medical Device User Fee and Modernization Act of 2002, Validation Data in Premarket Notification Submissions (510(k)s) for Reprocessed Single-Use Medical Devices, http://www.fda.gov/cdrh/ode/guidance/1216.html.
3. We recommend you provide a physical description of the device (e.g., size, weight, dimensions) with legible dimensional drawings.
B. Principles of Operation
We recommend you describe the method of operation, including, but not limited to, the information described below.
1. The means by which the blade moves across the cornea to perform a cut, the:
? advancement rate of the blade (mm/sec)
? oscillation rate of the blade (rpm)
? manual, electric (AC or DC), or pneumatic motor, and specifications
? use of rails, gears, etc.
? description of any other movement of the blade.
2. A description of the cut produced, including the:
? type of hinge or flap (nasal or superior)
? methods and components used to produce variable hinge, diameter, or thickness, if appropriate
? nominal flap thickness(es)
? nominal flap diameter(s)
? nominal hinge widths(s).
3. The means by which the blade is halted for the creation of a hinge or flap (e.g., a mechanical stop or software control).
4. The means by which the keratome attaches to the cornea (e.g., a vacuum fixation ring), the vacuum produced, and the maximum intraocular pressure (IOP) achieved during fixation.
5. Any diagrams and pictures that illustrate the points above.
C. Keratome Blade
We recommend you include a description of the keratome blade and blade holder, including, but not limited to:
1. An engineering drawing of the blade that includes the dimensions and tolerances of the blade (including width, length, thickness, and bevels), blade holder (if applicable), and the mounting holes in the blade (if applicable).
2. A complete description of the materials in the blade (e.g., types and grades) and in the blade holder that includes any applicable ASTM standards.
3. The identity of any residue (e.g., oils) remaining on the blade due to the manufacturing process.
4. The hardness and sharpness of the blade with a description of the tests employed to measure each.
In the table below, FDA has identified the risks to health generally associated with the use of the keratome and the keratome blades addressed in this document. The measures recommended to mitigate these identified risks are given in this guidance document, as shown in the table below. We recommend that you conduct a risk analysis to identify any other risks specific to your device and include the results of this analysis. The 510(k) should also describe the risk analysis method used. If you elect to use an alternative approach to address a particular risk identified in this document, or have identified risks additional to those in this document, you should provide sufficient detail to support the approach you have used to address that risk.
Section 7. Preclinical assessment
Section 8. Software assessment
Section 12. Labeling
Inflammation and Infection (e.g., keratitis, epithelial ingrowth, debris in the interface)
Section 10. Material Characterization and Biocompatibility
Section 11. Validation of Cleaning and Sterilization
Section 9. Electrical Safety Assessment
7. Preclinical Assessment
We recommend you provide data from validation testing of your keratome. This testing should address the accuracy, precision, and quality of the corneal flaps produced by your device, as well as the overall design of the device at a system level.
A. Validation of Cut
We recommend you provide the mean flap thicknesses, flap diameters, and hinge widths when the keratome is used in a statistically justifiable number of pig or cadaver eyes (e.g., 30 eyes per diameter and thickness). We recommend you test all the combinations of flap thicknesses, flap diameters, and hinge widths. We also recommend you provide data showing the nominal values, mean values, repeatability limits (i.e., the variability associated with cuts on a series of eyes using the same device and operator), and reproducibility limits (i.e., the variability associated with several series of eyes using different devices and operators) for all measured quantities. A tabular format of this data is desirable. We recommend you fully describe all associated test methods. We also recommend you provide general comments on your results, specifically addressing:
? the quality of the stromal bed produced (smooth, saw tooth, rough or other appropriate description)
? quality of the flap produced
? any significant differences between the nominal and measured values, wide variances or outliers, if present
? any anomalies noticed during the testing or in the data
? why you believe the flaps, hinges and stromal beds produced by your device are clinically acceptable.
If the device is an epikeratome, we recommend you also perform testing to determine the percentage of successful flaps (i.e., no residual patches of epithelium and an intact flap), percentage of partial cuts, percentage of torn flaps, and percentage of eyes with cellular debris requiring additional scraping. (Note that flap thickness testing is not recommended for epikeratomes, but flap diameters and hinge widths should be validated as described above.) We recommend you fully describe all associated test methods and provide general comments on your results. Specifically, we recommend that your comments explain why the rates of unsuccessful flaps, partial cuts, torn flaps, and cellular debris you observe are clinically acceptable.
You may include any available clinical data to support the validation information recommended above for keratomes and epikeratomes.
B. Validation of Device Design
We recommend you conduct system level validation testing to ensure all hardware and software systems in the device are functioning properly. We recommend you validate all alarms and warnings (e.g., warnings or alarms for insufficient vacuum or improper assembly) under realistic fault conditions. For more details on software validation, please refer to Section 8 below.
8. Software Validation
Manufacturers of class I devices automated with computer software must comply with the requirements of Design Controls (21 CFR 820.30, Subpart C) under the Quality System Regulations, 21 CFR 820.30(a)(2)(i). In accordance with these requirements, you must perform design validation, which includes a software validation and risk analysis, where appropriate, and document the design validation results in your design history file as described under 21 CFR 820.30(g).
Please refer to the Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices, http://www.fda.gov/cdrh/ode/guidance/337.html, for a discussion of the software documentation that you should provide. Please also refer to the General Principles of Software Validation, http://www.fda.gov/cdrh/comp/guidance/938.html, for a discussion of general principles that the FDA considers applicable to the validation of medical device software.
We encourage you to take advantage of any recognized software standards and provide statements or declarations of conformity as described in the FDA guidance, Use of Standards in Substantial Equivalence Determinations, http://www.fda.gov/cdrh/ode/guidance/1131.html. Please visit the following website to search for the standards that have been recognized when a medical device contains software, http://www.accessdata.fda.gov/scripts/c ... search.cfm.
9. Electrical Safety and Electromagnetic Compatibility
We recommend you address the electrical safety and electromagnetic compatibility of your device by following both standards below or equivalent methods:
? International Electrotechnical Committee (IEC) standard IEC 60601-1, Medical Electrical Equipment Part 1: General Requirements for Safety
? IEC 60601-1, Part 1-2: General Requirements for Safety - Collateral Standard: Electromagnetic Compatibility - Requirements and Tests
Electromagnetic compatibility (EMC) encompasses both emissions (interference with other electronic devices) and immunity (interference with device performance created by emissions from other electronic devices). We recommend you evaluate the EMC of your device as discussed below.
EMC testing should demonstrate that the device will not adversely interfere with the performance of other electronic devices (emissions). Testing should include radio frequency (RF) electromagnetic, low frequency magnetic, and conducted emissions testing.
EMC testing should also demonstrate that the device will perform as expected in the presence of other electrical and electronic devices or other sources of electromagnetic disturbance (EMD) in the intended environment of use (immunity). The device should operate in an acceptable manner (few EMC standards require operation within specification) during and after exposure to various forms of electromagnetic disturbance. Testing should include:
? electrostatic discharge (ESD)
? radiated RF electromagnetic fields
? electrical fast transient and bursts
? surges
? conducted RF electromagnetic energy
? voltage dips, short interruptions, and voltage variations on power supply input lines
? low- frequency magnetic fields
? quasi-static electric fields.
We recommend that you test your device according to IEC 60601-1-2 Medical Electrical Equipment ? Part 1: General Requirements for Safety; Electromagnetic Compatibility ? Requirements and Tests (Second Edition, 2001) to demonstrate the EMC characteristics of your device.
10. Material Characterization and Biocompatibility
FDA recommends you conduct biocompatibility testing as described in the FDA guidance, Use of International Standard ISO-10993, Biological Evaluation of Medical Devices Part-1: Evaluation and Testing (the Biocompatibility guidance).5 We consider keratome blades as devices with limited contact with breached or compromised surfaces. We recommend you select biocompatibility tests appropriate for the duration and level of contact with your device. You should prepare samples for biocompatibility testing in a way that reflects the actual conditions of use (e.g., if the material will be heated during use, it should be heated to adequate temperature prior to testing). If identical materials and identical material processing are used in a predicate
5 http://www.fda.gov/cdrh/g951.html
device with the same type and duration of patient contact, you may identify the predicate device in lieu of providing biocompatibility testing.
For single use devices that are provided sterile, we recommend you provide sterilization information described in the guidance entitled, Updated 510(k) Sterility Review Guidance K90-1.6 The device should be sterile with a sterility assurance level (SAL) of 1 x 10-6 using a sterilization cycle validated in accordance with the Quality System Regulation (QSR) 21 CFR Part 820. In addition, we recommend you provide a description of the packaging that maintains the device?s sterility.
If the device is reusable, we recommend you identify the method that you used to validate the cleaning, disinfection, and sterilization of your device. (See also Section 12. Labeling.) In addition, we recommend you specify any limit on the number of times re-sterilization and reuse can be done without adversely affecting the safety, effectiveness, or performance of the device.
The premarket notification must include labeling in sufficient detail to satisfy the requirements of 21 CFR 807.87(e). The following suggestions are intended to assist you in preparing labeling that satisfies the requirements of 21 CFR Part 801.7
As a prescription device, under 21 CFR 801.109, the device is exempt from having adequate directions for lay use. Nevertheless, under 21 CFR 807.87(e), we recommend providing clear and concise instructions that delineate the technological features of the specific device and how the device is to be used on patients. Instructions should encourage local/institutional training programs designed to familiarize users with the features of the device and how to use the device in a safe and effective manner.
The user?s manual should include instructions for cleaning and sterilization procedures, if appropriate.
Your labeling should include indications for use, for example:
A keratome is indicated for cutting the cornea prior to lamellar (partial thickness) transplant or to create a flap in the cornea prior to LASIK surgery or prior to another procedure requiring a corneal flap.
6 http://www.fda.gov/cdrh/ode/guidance/361.html.
7 Although final labeling is not required for 510(k) clearance, final labeling must comply with the requirements of 21 CFR Part 801 before a medical device is introduced into interstate commerce. In addition, final labeling for prescription medical devices must comply with 21 CFR 801.109. Labeling recommendations in this guidance are consistent with the requirements of Part 801.
We also recommend that you include the nominal values, mean values, repeatability limits, and reproducibility limits for flap thickness, flap diameter, and hinge width in the user?s manual. You should also include the basic details about the study design (e.g., porcine or human eyes, sample size) used to determine these values.
Appendix ? Information for Replacement Keratome Blades
A. For each keratome, for which your blades are intended for use, we recommend you provide the:
? name of the keratome original equipment manufacturer (OEM)
? model of the keratome
? 510(k) number (if known) for each keratome.
B. We recommend you include a side-by-side comparison for each of your blades with each keratome?s OEM blade. We also recommend you address the following parameters for each of your blades and the OEM blades. For each comparison and each parameter in each comparison, we recommend you comment on the similarities between blades and explain the impact on blade performance of any differences you observe. We also recommend presenting each comparison clearly and separately; a tabular format is desirable.
We recommend you include a diagram (drawing or manufacturing blue print) of the device that illustrates the dimensions you have measured. We recommend you also include a key to the diagram (a tabular format is desirable) that shows the dimensions and tolerances for your device (blade, blade holder, keratome head, as appropriate).
We recommend you provide all of the measurements (mean, standard deviation, and measurement precision for each) of the blade (length, width, thickness, and bevels), blade holder (if applicable), mounting holes in blade (if applicable), keratome head (if applicable), and any other specifications to compare your device and the OEM blades. We also recommend you measure a statistically justifiable number of your blades and the OEM blades, for example 30 blades.
We recommend you identify and compare (by ASTM standard, specification, type, grade, certificate of analysis, etc.) the materials in the final product of your blade and the OEM blade: the blade, blade holder (if applicable), and coatings on the blade (if applicable). We also recommend you identify any remaining substances on the blade due to polishing or sharpening.
We recommend you compare the hardness of the blade and the OEM blade and indicate the test used to measure the hardness.
We also recommend you compare the sharpness of your blade and the OEM blade and indicate the test used to measure the sharpness. Testing may combine photomicrographs and validation testing, or be stand-alone sharpness tests.
C. Preclinical Assessment: See Section 7. Preclinical Assessment. We also recommend you provide documentation of validation testing demonstrating the equivalency of your blade to the OEM. For each comparison and each parameter in each comparison, we recommend you comment on the similarities between the blades and explain the impact of any differences you observe on the blade performance.
D. Sterilization: See Section 11. Sterilization.
E. Labeling: See Section 12. Labeling. Labeling should include an indications for use that identifies the OEM manufacturers and model numbers your blades are intended for use with.
F. FDA recommends that manufacturers of replacement keratome blades include the accuracy, repeatability, and reproducibility information for all combinations of flap thickness, flap diameter, and hinge width compatible with the OEM keratome in the package labeling.
Posted: Sat Sep 30, 2006 12:49 pm
http://www.fda.gov/cdrh/reuse/
Posted: Wed Oct 11, 2006 12:39 pm
http://www.fda.gov/ola/2006/suds0926.html
Daniel Schultz, M.D., Director
Mr. Chairman and Members of the Committee, I am Dr. Daniel Schultz, Director, Center for Devices and Radiological Health (CDRH) at the Food and Drug Administration (FDA or the Agency). I consider device safety to be of utmost importance and appreciate your invitation and the opportunity to discuss this issue. Let me say at the outset that I believe FDA currently has many tools to ensure the safety, effectiveness, and manufacturing quality of reprocessed, single-use devices (SUDs).
FDA has been actively engaged in the SUD reuse issue for some time, and our efforts have included research, outreach, pre-market review, inspections, and compliance investigations. We have held numerous public meetings and conferences with industry, healthcare professionals, and consumers over the years to determine the extent, magnitude, and changing nature of this practice. FDA has carefully evaluated and conducted research to develop the scientific basis for addressing SUD reprocessing. We have inspected third party reprocessors, evaluated and investigated reports of patient injuries, and reviewed numerous pre-market submissions. Taken together, the Agency believes that these efforts have provided, and will continue to provide, reasonable assurance of safety and effectiveness of reprocessed SUDs for patients.
I will begin with a brief overview of our regulatory authorities for medical devices. A medical device as defined by Federal law encompasses several thousand health products, from simple articles such as tongue depressors and heating pads, to cutting-edge and complex devices such as implantable defibrillators and robotic equipment for minimally invasive surgery.
The Medical Device Amendments of 1976 to the Federal Food, Drug, and Cosmetic (FD&C) Act gave FDA specific authority to regulate the safety and effectiveness of medical devices. Medical devices are assigned to one of three ?classes.? Class I is the lowest risk category of device and includes items such as adhesive bandages. Class II, or medium-risk category of device, includes devices such as intravenous catheters and powered wheelchairs. Class III is the highest risk category of device and includes devices such as heart valves and coronary stents.
THE REGULATION OF REPROCESSED SINGLE USE MEDICAL DEVICES
The reprocessing of SUDs is legally permissible in the United States under the FD&C Act. Currently, only Class I and II SUD device types have been cleared by FDA for reprocessing. No Class III SUDs have been cleared/approved for reprocessing.
In August 2000, FDA issued a guidance document for industry and staff entitled ?Enforcement Priorities for Single-Use Devices Reprocessed by Third Parties and Hospitals.? This document set forth FDA?s priorities for enforcing pre-market submission and post-market requirements for manufacturers who wished to market reprocessed SUDs. The guidance document stated that any third party or hospital reprocessor should comply with requirements pertaining to: registration and listing, medical device reporting, medical device tracking, medical device corrections and removals, the quality system regulation, labeling, and pre-market submission. Essentially, third party firms and hospitals reprocessing SUDs were placed in the same regulatory framework as original equipment manufacturers (OEMs).
Prior to issuance of this guidance, reprocessing of SUDs was frequently performed by hospital personnel without regulatory oversight or regard to the level of device risk. In addition, many third party reprocessors contracted with hospitals to perform similar tasks and these contractors did not consistently adhere to FDA?s Good Manufacturing Practice Requirements.
CHANGES ENACTED WITH MDUFMA
In 2002, with enactment of the Medical Device User Fee and Modernization Act (MDUFMA), Congress mandated a number of new requirements for SUD reprocessors including, for certain SUDs, the pre-market submission of data to the Agency that exceeded the requirements for OEMs. In addition to the requirements specified in our 2000 Guidance Document, certain reprocessed SUD types that potentially could pose the greatest risk of infection and inadequate performance following reprocessing and that were previously exempt from any pre-market submission requirements, are no longer exempt.
MDUFMA also created a new type of pre-market submission, called a ?pre-market report? (PMR), for Class III reprocessed SUDs that otherwise would have required a pre-market approval application. Among other information, a PMR must include validation data regarding cleaning, sterilization, and functional performance of the reprocessed device to ensure it is substantially equivalent to a legally marketed device. To date, only one PMR has been submitted to the Agency and it was later withdrawn by the firm.
In addition, MDUFMA required a change to FDA?s MedWatch voluntary and mandatory reporting forms (Forms 3500 and 3500A, respectively) to facilitate the reporting of adverse events involving reprocessed SUDs.
Finally, MDUFMA required, as of August 1, 2006, that reprocessed SUDs prominently and conspicuously bear the name, abbreviation, or symbol of the reprocessor on the device itself, on an attachment to the device, or on a detachable label, depending on the physical characteristics of the device and whether the device has been marked by the OEM.
PRE-MARKET REVIEW OF REPROCESSED SUDs
Under the FD&C Act, before introducing a device to market, manufacturers must submit a Notification of Intent to Market a Device (510k) and obtain FDA clearance, unless the device has been exempted. MDUFMA required FDA to identify previously 510(k)-exempt device types that, if reprocessed as a SUD, would now require 510(k) pre-market review, including the submission of validation data. In addition, MDUFMA required that FDA identify SUDs that were already subject to 510(k) pre-market requirements, but that would now also require the submission of validation data. Required validation data include cleaning and sterilization data, and functional performance data demonstrating that each SUD will remain substantially equivalent to its predicate device after the maximum number of times the device is intended to be reprocessed.
The criteria used to determine which reprocessed SUD types would no longer be exempt from pre-market notification requirements and would require 510(k)s with validation data, and which reprocessed SUDs already subject to the 510(k) requirements also would now be subject to the additional requirement of validation data are available on the Internet at: http://www.fda.gov/OHRMS/DOCKETS/98fr/03-10413.html.
Using these criteria, FDA identified all previously exempt ?critical? and ?semi-critical? devices that were high-risk. These devices would no longer be exempt from 510(k) requirements and SUD reprocessors of these device types would be required to submit 510(k)s with validation data and receive clearance in order to continue marketing these devices.
In addition, the requirements and the lists of devices that were newly subject to these requirements were published in the Federal Register. FDA has added other reprocessed SUD types to these lists as we become aware of information that warrants their inclusion.
On June 1, 2004, FDA issued a revised ?Guidance for Industry and FDA Staff; Medical Device User Fee and Modernization Act of 2002, Validation Data in Pre-market Notification Submissions (510(k)s) for Reprocessed Single-Use Medical Devices.? This document describes the types of validation data that FDA recommends be submitted on cleaning, sterilization, and functional performance of certain reprocessed SUDs to ensure that they are substantially equivalent to the predicate device. Additionally, this document describes the timeframe for FDA?s reviews of these validation data submissions, and what actions the Agency intends to take if it finds a reprocessed SUD to be Not Substantially Equivalent (NSE) to the predicate device.
As of September 2006, FDA has received nearly 200 pre-market notification 510(k) submissions for reprocessed SUDs. These submissions cover from one, to as many as several hundred, device models. Of the almost 200 submissions, approximately 67 percent have been cleared by FDA. The remaining were not cleared for such reasons as inadequate validation data, lack of necessary information from the reprocessor, withdrawal of the application by the submitter, or lack of response to FDA?s request for data. (Approximately 88 percent of 510(k)s for all other devices are cleared and approximately 3.4 percent are found NSE to the predicate device.)
FDA?s inspectional program serves as a bridge between pre- and post-market activities. Since 2000, on average, FDA has conducted inspections of reprocessor firms once every two years, a rate considerably higher than the one inspection in four years for OEMs. Of the seven firms currently known to be reprocessing, all have been inspected within the last two years. FDA continues to evaluate newly registered firms to confirm whether they are performing SUD reprocessing and updates its inspectional plan as required.
POST-MARKET SURVEILLANCE FOR REPROCESSED SUDs
Post-market monitoring of device-related adverse events (AEs) and product problems is accomplished through the Medical Device Reporting (MDR) system. MDR reports include deaths, serious injuries, and device malfunctions. Healthcare facilities are required to report deaths suspected to be device-related to both FDA and the manufacturer/reprocessor. They are required to report serious injuries to the manufacturer/reprocessor.
FDA also receives voluntary reports, generally from healthcare professionals, through its MedWatch reporting system. As previously mentioned, under MDUFMA, the MedWatch reporting form 3500A was revised to include a data entry field (D8) to ask if the device associated with the reported event was a reprocessed SUD. This question was added to the form to enhance the Agency?s ability to quickly identify and investigate reports of problems associated with reprocessed SUDs.
FDA responds to reports of death or serious injury by investigating the report and taking appropriate follow-up actions as needed. Follow-up actions may include enforcement actions and/or the issuance of a public health notification to alert the healthcare community of the Agency?s concerns.
As you know, on January 24, 2006, I and others briefed this Committee about SUD reprocessing. At that time, we provided background information including the current regulatory framework and AE data. Specifically, we searched our Manufacturer and User Facility Device Experience (MAUDE) database for reports from October 22, 2003, to December 13, 2005, that were coded as adverse events associated with reprocessed SUDs. The search produced 176 reports of death, serious injury, and/or device malfunction; however, analysis of these reports did not disclose a clear causative link between a reprocessed SUD and subsequent patient injury or death.
In July 2006, the Agency updated the search to include all reports entered into the MDR, MAUDE, and MedWatch databases between December 2005 and July 2006. FDA has received a total of approximately 434 reports, including MedWatch forms, where the reprocessed SUD field was checked ?yes.? Our analysis of these reports determined that many of the devices were not reprocessed SUDs. Rather, they were implanted devices or devices that were designed to be re-usable and, therefore, were not reprocessed SUDs. Of the 434 reports, approximately 65 reports actually involved or were suspected to involve reprocessed SUDs, and were reviewed by FDA. The final analysis of the reports found that the types of adverse events reported to be associated with the use of SUDs were the same types of events that also are being reported for new, non-reprocessed devices. Therefore, it was unclear whether the device, the medical condition of the patient, the medical procedure, or other confounding factors caused or contributed to the adverse event.
FEEDBACK FROM A SAMPLING OF MEDSUN HOSPITAL FACILITIES THAT USE REPROCESSED SUDs
FDA?s Medical Product Safety Device Network (MedSun) is comprised of over 350 hospitals that have been recruited and specifically trained to identify and report device problems. The hospitals in this program are broadly representative of U.S. healthcare facilities. FDA staff talked with representatives from more than 50 of these facilities to obtain feedback on their experience with using reprocessed SUDs.
The MedSun respondents who gave us feedback represented various occupations in hospitals, including materials management, biomedical and clinical engineering, risk management, infection control, surgical services, nursing staff, supply utilization, and equipment management. Staff being interviewed responded overwhelmingly that they view the use of reprocessed SUDs as providing a significant cost savings to their facilities and as being an environmentally sound practice.
There was considerable variation in the devices being reprocessed at the various facilities and the degree of acceptance of this practice by individual practitioners within the facilities. None of the participants we spoke with reported specific problems with SUD-related infections, but they also pointed out that, if an infection occurred, it would be difficult to discern whether the reprocessed SUD was the cause. It also is interesting to note that the participants did not report a greater concern with mechanical problems associated with reprocessed SUDs compared to un-reprocessed SUDs. In general, the participants had a favorable view of reprocessed SUDs used in their facilities. They also stated that they relied heavily on FDA oversight to ensure safety and effectiveness and to provide objective information on reprocessed SUDs.
ONGOING FDA ACTIVITIES
The Agency continues to review and assess the practice of reprocessing SUDs.
CDRH established an active internal work group to ensure that review scientists remain current with the evolving scientific literature and new consensus standards that are relevant to the reprocessing of SUDs.
CDRH has convened a second work group, called the ?Post-market Issue Action Team,? to develop a long-term strategy for monitoring, evaluating, and communicating information about reused SUDs.
CDRH continues to submit reprocessor inspection requests to the Office of Regulatory Affairs to schedule inspections of reprocessor facilities to assess conformance with the Quality System Regulation.
CDRH periodically updates its reuse webpage so that healthcare facilities and providers will have current information on legally marketed, reprocessed SUDs. Recently, easy-to-read tables listing FDA requirements for specific reprocessed SUD types were added to the website. In addition, we improved accessibility and added instructions to the publicly searchable FDA pre-market databases. These databases allow the user to search in real-time for recent and past clearances. (http://www.fda.gov/cdrh/reuse/index.html)
CDRH regularly updates guidance to industry and FDA reviewers on validation data requirements for reprocessed SUDS.
CDRH regularly updates the list of reprocessed SUDs subject to the additional pre-market requirements imposed by MDUFMA.
CDRH is conducting research to develop/establish ?acceptable? SUD cleaning criteria.
CDRH is collaborating with two local healthcare facilities to help monitor changes in the design of some SUDs and identify new SUDs being reprocessed.
On September 25, 2006, FDA published two rules: the direct final rule for Medical Devices; Reprocessed Single-Use Devices; Requirement for Submission of Validation Data; and a proposed rule for Medical Devices; Reprocessed Single-Use Devices; Requirement for Submission of Validation Data; Companion to Direct Final Rule (proposed rule). These amendments will help ensure that reprocessors submit the data, including cleaning, sterilization, and functional performance data, needed to demonstrate that their device is substantially equivalent to the predicate device.
Available data show that SUDs can be reprocessed with a reasonable assurance of safety and effectiveness. FDA believes that reprocessed SUDs that meet FDA?s regulatory requirements are as safe and effective as a new device. The law and regulations in place are designed to protect the public health by assuring that the practice of reprocessing and reusing SUDs is based on sound science. FDA continues to monitor the performance of these devices and to assess and refine our ability to regulate these devices appropriately.
Mr. Chairman, thank you again for the opportunity to address this important topic. I will be happy to answer any questions.
Posted: Sat Oct 21, 2006 11:37 pm
J Cataract Refract Surg. 2003 Apr;29(4):825-31.
Evaluation of corneal flap dimensions and cut quality using the SKBM automated microkeratome.
Viestenz A, Langenbucher A, Hofmann-Rummelt C, Modis L, Viestenz A, Seitz B.
Department of Ophthalmology, University of Erlangen-Nurnberg, Germany. Arne.Viestenz@t-online.de
PURPOSE: To evaluate flap dimensions and cut quality with repeated blade use of the automated Summit Krumeich-Barraquer microkeratome (SKBM [LadarVision]).
SETTING: Department of Ophthalmology, University Erlangen-Nuremberg, Erlangen, Germany.
METHODS: The SKBM (160 microm plate, intended flap diameter 9.0 mm) was used to perform a corneal hinged flap in 35 pig cadaver eyes. Seven blades were reused 5 times each. The flap diameter was measured by planimetry, and the thickness was assessed by ultrasonic pachymetry. Scanning electron microscopy (SEM) of blades and stromal beds was performed.
RESULTS: With single use of the blade, the mean central flap thickness was 145 microm +/- 25 (SD). The vertical/horizontal flap diameter was 9.0 +/- 0.03 mm/8.6 +/- 0.03 mm. No thickness gradient was observed from the incision (138 +/- 31 microm) to the flap hinge (130 +/- 30 microm). If the blade was used more than 2 times, the flap was thinner at the incision (157 +/- 34 microm versus 124 +/- 20 microm; P =.003) and the hinge (143 +/- 24 microm versus 122 +/- 31 microm; P =.04), but the central thickness remained unchanged. With multiple use of the blade, SEM analysis showed increasing cut irregularity, more tissue remnants on the blade surface, and a progression in blade irregularities (up to 9.3 microm).
CONCLUSIONS: Reproducible flap size and thickness can be obtained with single use of stainless steel blades in the SKBM. With multiple use, the quality of the blades and the stromal bed deteriorates and the peripheral thickness of the flaps decreases. Thus, single use of blades is recommended.
Posted: Sat Oct 21, 2006 11:39 pm
Am J Ophthalmol. 2000 Jan;129(1):59-67.
Experimental evaluation of two current-generation automated microkeratomes: the Hansatome and the Supratome.
Behrens A, Langenbucher A, Kus MM, Rummelt C, Seitz B.
Department of Ophthalmology, University of Erlangen-Nurnberg, Erlangen, Germany. ashleybehrens@hotmail.com
PURPOSE: To compare flap dimensions, cut quality, and blade deterioration after reuse in an experimental setting using two current-generation microkeratomes for laser-assisted in situ keratomileusis.
METHODS: Two pivoting-head principle microkeratomes, the Hansatome and the Supratome, were used to perform a corneal flap in 50 freshly enucleated pig cadaver eyes, with an intended thickness of 160 microm. Provided stainless steel blades were used from one to five times. Flap diameter was measured by planimetry and thickness calculated using ultrasonic pachymetry at three different locations. Scanning electron microscopy of stromal beds and blades' cutting edges were performed to assess the cut and blade deterioration after repeated use. RESULTS: Mean flap central thickness (Hansatome/Supratome) was 151 microm (SD 18)/192 microm (SD 32). Progressive thinning/thickening of the flap was observed in the direction toward the hinge (P = .003/P = .021). Mean vertical flap diameters of 8.9 mm (SD 0.3)/8.0 mm (SD 0.4) differed significantly (P = .001). No correlation was found between thickness and diameter (r = 0.03, P = .935/r = 0.12, P = .603). At scanning electron microscopy, smooth cuts were observed with both keratomes using a new blade. Periodical chatter lines at keratectomy edge were present and were more pronounced after blade reuse. Cut quality, blade deterioration, and small tissue remnants on the blade surface were noted with repeated blade use, especially using the Supratome.
CONCLUSIONS: Local flap thickness and flap diameter variations are inherent to the instrument used. Comparable cut-surface quality can be obtained with new blades. Although cut and blade deterioration appears to be minor after two reuses, the presence of tissue remnants on the blade surface still limits its reuse.
Posted: Sat Oct 21, 2006 11:42 pm
J Refract Surg. 2004 May-Jun;20(3):258-64.
Flap quality in single versus multiple use of the same blade in the Flapmaker microkeratome.
Modis L Jr, Langenbucher A, Behrens A, Seitz B.
University of Debrecen, Medical and Health Science Centre, Department of Ophthalmology, Nagyerdei krt 98, H-4012 Debrecen, Hungary. lmodis@dragon.klte.hu
PURPOSE: We evaluated experimentally the variability of cut thickness, flap diameter, and cut quality produced by the Flapmaker corneal microkeratome (IOLTech), with single and repeated use of the same cutting blade.
METHODS: Keratectomy was performed with twelve cutting heads (8.5-mm diameter, 160-microm cutting depth) on 47 corneas and with six cutting heads (8.0-mm diameter, 180-microm cutting depth) on 18 freshly enucleated swine eyes in a repeated manner. Ultrasonic pachymetry was determined at the initial, central, and final microkeratome pass zones, first before the flap was created and subsequently after the flap was reflected. Flap diameter was measured by planimetry. After the procedure stromal portions were submitted for scanning electron microscopy.
RESULTS: On the first blade use, mean central flap thickness was 145 +/- 32 microm and mean vertical flap diameter was 8.4 +/- 0.26 mm with the 8.5-mm blades. With the 8.0-mm blades, mean central flap thickness was 155 +/- 23 microm and mean vertical flap diameter was 8.0 +/- 0.27 mm. Scanning electron microscopy disclosed smooth cut surfaces when new blades were used, but with repeated blade use, increasingly prominent stromal bed folds were observed.
CONCLUSIONS: The evaluated blades produced reproducible flap size and thickness and good cut quality with single use, but after the first use, cut quality markedly deteriorated. Repeated use of Flapmaker cutting blades is not recommended.
Posted: Sun Oct 22, 2006 12:15 am
J Refract Surg. 2000 Jan-Feb;16(1):83-9.
Evaluation of corneal flap dimensions and cut quality using the Automated Corneal Shaper microkeratome.
Behrens A, Seitz B, Langenbucher A, Kus MM, Rummelt C, Kuchle M.
Department of Ophthalmology, University of Erlangen-Nurnberg, Erlangen, Germany.
PURPOSE: To evaluate flap dimensions and cut deterioration with repeated blade use in an automated microkeratome. METHODS: The Automated Corneal Shaper (Chiron-Adatomed, Munich, Germany), 160-microm plate attached, was used to make a corneal flap in 90 pig cadaver eyes, reusing blades up to five times. Flap diameter was measured by planimetry and thickness was calculated by ultrasound pachymetry. Scanning electron microscopy of stromal beds and blade cutting edges was performed to assess cut deterioration after repeated blade use. RESULTS: Mean flap central thickness was 125 +/- 32 microm. Mean vertical flap diameter was 7.6 +/- 0.4 mm. No correlation was found between thickness and diameter (r = 0.15, P = .45). Progressive thinning of the flap was observed in the direction of the flap hinge. Smooth cuts (using new blades) with periodic chatter lines at the keratectomy edge and in the stromal bed were observed with scanning electron microscopy. Increasing tissue remnants on the stromal bed and decreasing cut quality occurred with repeated blade use. Blades showed larger tissue remnants, nicks, and even folds on the cutting edge proportional to the number of times blades were used. CONCLUSION: Satisfactory cut quality and reproducibility were obtained after a single use of stainless steel blades in the Automated Corneal Shaper microkeratome. Cut quality was degraded dramatically by repeated use of blades.
Posted: Sun Feb 04, 2007 1:13 am
Arq Bras Oftalmol. 2006 Nov-Dec;69(6):845-9.
[Examination of blades used in LASIK by scanning electron microscopy.]
?	Soares FS,
?	Casanova FH,
?	Campos M,
?	Nishiwaki-Dantas MC,
?	Dantas PE.
Departamento de Oftalmologia, Santa Casa de Misericordia de Sao Paulo, Sao Paulo, SP, Brasil.
PURPOSE: To evaluate and compare, by scanning electron microscopy (SEM), the sharpness of the edge of brand new surgical blades and consecutively used surgical blades in laser-assisted in situ keratomileusis (LASIK).
METHODS: Tewnty-five AccuGlide(R) (Bausch & Lomb, USA) surgical blades were evaluated, divided in to 3 groups: Group 1 (control), non-used surgical blades; Group 2, ten surgical blades used twice (simultaneous bilateral procedure); Group 3, ten surgical blades used four times (two consecutive simultaneous bilateral procedures). Each blade was analyzed by SEM at four random points, two central and two peripheral points, with magnification of 50x, 350x, and 1,000x.
RESULTS: Blade body irregularities and organic material were observed on all used surgical blades (Groups 2 and 3), but not on new surgical blades (Group 1). In addition, Group 3 revealed more irregularities in both central (p=0.0094) and peripheral points (p=0.0098) than Group 2, as well as organic material deposition (p=0.0204 and p=0.0909, respectively). Neither metalic material nor irregularities in the cutting edge of the blade were observed in any group.
CONCLUSION: No difference regarding the cutting edge was observed between new and blades reused up to four times, however irregularities and organic material were observed in all reused blades. Reusing blades for LASIK may produce structural changes and its clinical implications need to be evaluated due to the possible relation with interlamellar postoperative complications.
Posted: Sat Jun 02, 2007 10:07 pm
J Refract Surg. 2007 May;23(5):472-6.
Buttonholes during LASIK: etiology and outcome.
Lichter H, Stulting RD, Waring GO, Russell GE, Carr J.
In View, Atlanta, Ga, USA. lichter_henia@yahoo.com
PURPOSE: To report the clinical features and outcome of eyes with flap buttonhole during LASIK.
METHODS: A retrospective review was performed to identify eyes that developed flap buttonhole during Hansatome microkeratome translation. Pre-, intra-, and postoperative data were obtained to identify factors predictive of buttonhole.
RESULTS: Five patients with buttonhole were identified from June 2001 through September 2002 (5 [0.06%] eyes of 7672 primary LASIK procedures). Mean patient age was 49.2 +/- 11.3 years (range: 37 to 66 years). Mean preoperative spherical equivalent refraction was 4.92 +/- 2.90 diopters (D) (range: -2.25 to -9.50 D). Mean keratometry was 45.59 +/- 1.15 D (range: 43.90 to 47.60 D). All 5 flap buttonholes occurred in the second of 2 consecutively treated eyes (P = .03). Buttonhole occurred in 2 (0.26%) of 778 eyes where the 160-microm microkeratome plate was used, and 3 (0.06%) of 4350 eyes where the 180-microm plate was used (P = .16). Two eyes received laser ablation at the time of buttonhole formation. In the untreated cases, the buttonhole flap itself caused a myopic spherical change of -0.50 D and 0.70 D of astigmatism. One of 5 eyes lost 2 lines of best spectacle-corrected visual acuity; this eye received laser ablation immediately after buttonhole formation.
CONCLUSIONS: Buttonholes are significantly more likely to occur in the second of two consecutively treated eyes. A new blade for the second eye when the flap in the first eye appears to be thin should be considered. Caution should be exercised when considering laser ablation immediately following buttonhole formation.
Our study demonstrated that the second eye was signifi cantly more at risk for buttonhole formation than the fi rst eye, which is consistent with previous reports that fl aps are thinner in the second eye when the same microkeratome blade is used on both eyes of a patient having bilateral same-session LASIK.
Buttonholes occur more frequently in the second eye of bilateral simultaneous LASIK surgeries when the same blade is used for both eyes.
Last edited by Broken Eyes on Mon Sep 03, 2007 2:51 pm, edited 1 time in total.
Posted: Thu Jun 21, 2007 12:42 pm
A Cluster of Nocardia Keratitis After LASIK
After three patients were diagnosed with infection, he recalled the fourth patient and found bilateral keratitis as well. The primary surgeon managed this patient with a similar course of treatment as ours (ie, amikacin and cotrimoxazole administration), and the infiltrate finally resolved. He also disclosed that all cases were operated using the same blade and microkeratome.
Buttonholes During LASIK: Etiology and Outcome
Journal of Refractive Surgery Vol. 23 No. 5 May 2007
Henia Lichter, MD, BSc; R. Doyle Stulting, MD, PhD; George O. Waring III, MD, FACS, FRCOphth; Gregg E. Russell, OD, FAAO; Jonathan Carr, MD, MA, FRCOphth
To report the clinical features and outcome of eyes with flap buttonhole during LASIK.
A retrospective review was performed to identify eyes that developed flap buttonhole during Hansatome microkeratome translation. Pre-, intra-, and postoperative data were obtained to identify factors predictive of buttonhole.
Five patients with buttonhole were identified from June 2001 through September 2002 (5 [0.06%] eyes of 7672 primary LASIK procedures). Mean patient age was 49.2?11.3 years (range: 37 to 66 years). Mean preoperative spherical equivalent refraction was ?4.92?2.90 diopters (D) (range: ?2.25 to ?9.50 D). Mean keratometry was 45.59?1.15 D (range: 43.90 to 47.60 D). All 5 flap buttonholes occurred in the second of 2 consecutively treated eyes (P=.03). Buttonhole occurred in 2 (0.26%) of 778 eyes where the 160-?m microkeratome plate was used, and 3 (0.06%) of 4350 eyes where the 180-?m plate was used (P=.16). Two eyes received laser ablation at the time of buttonhole formation. In the untreated cases, the buttonhole flap itself caused a myopic spherical change of ?0.50 D and 0.70 D of astigmatism. One of 5 eyes lost 2 lines of best spectacle-corrected visual acuity; this eye received laser ablation immediately after buttonhole formation.
Buttonholes are significantly more likely to occur in the second of two consecutively treated eyes. A new blade for the second eye when the flap in the first eye appears to be thin should be considered. Caution should be exercised when considering laser ablation immediately following buttonhole formation. [J Refract Surg. 2007;23:472-476.]
Posted: Fri Oct 05, 2007 2:07 am
http://www.tlcdocs.com/management_resou ... Potter.pdf
John W Potter, OD
National Director for Clinical Affairs
However, many providers of laser vision correction use the same microkeratome blade for several patients. Why? A microkeratome blade is an expensive item and a surgeon can reduce their procedure costs by reusing blades. Often this cost reduction is passed along in part to the patient by reducing the global fee or providing ?value pricing?. However, a skillful and thoughtful refractive surgeon does not reuse microkeratome blades. Experience tells us that the LASIK procedure itself causes the quality of the microkeratome blade to degrade if it is used too frequently, and that it is nearly impossible to detect the degree of blade degradation. That is to say, it is impossible to tell when a blade has been used too much, so that the risk of producing a very poor flap increases dramatically with each additional use. How much is too much? A less thoughtful refractive surgeon tests the limits continually. A thoughtful refractive surgeon knows better.