Guidance for Industry and FDA Staff 
 
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. 
 
 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Devices and Radiological Health 
 
Diagnostics and Surgical Devices Branch 
Division of Ophthalmic, Ear, Nose and Throat Devices 
Office of Device Evaluation 
 
  Contains Nonbinding Recommendations 
 
Preface 
 
 
Public Comment 
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 
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. 
  2 Contains Nonbinding Recommendations 
 
Table of Contents 
 
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 
 
 
 
  3 Contains Nonbinding Recommendations 
 
Guidance for Industry and FDA Staff 
 
Keratome and Replacement Keratome Blades 
Premarket Notification [510(k)] Submissions 
 
This guidance represents the Food and Drug Administration's (FDA's) current thinking on 
this topic.  It does not create or confer any rights for or on any person and does not operate to 
bind FDA or the public.  You can use an alternative approach if the approach satisfies the 
requirements of the applicable statutes and regulations.  If you want to discuss an alternative 
approach, contact the FDA staff responsible for implementing this guidance.  If you cannot 
identify the appropriate FDA staff, call the appropriate number listed on the title page of this 
guidance. 
 
1.  Introduction 
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 Least Burdensome Approach 
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. 
 
FDA's guidance documents, including this guidance, do not establish legally enforceable 
responsibilities.  Instead, guidances describe the Agency's current thinking on a topic and should 
be viewed only as recommendations, unless specific regulatory or statutory requirements are 
cited.  The use of the word should in Agency guidances means that something is suggested or 
recommended, but not required.  
 
  1 Contains Nonbinding Recommendations 
 
2.  Background 
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). 
3.  The Content and Format of an Abbreviated 510(k) 
Submission  
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). 
 
  2 Contains Nonbinding Recommendations 
 
Coversheet 
The coversheet should prominently identify the submission as an Abbreviated 510(k) and cite 
the title of this guidance document. 
 
Proposed labeling 
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.) 
 
Summary report 
We recommend that the summary report contain: 
 
Description of the device and its intended use   
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   
 
Description of device design  
We recommend that you include a brief description of the device design requirements. 
 
Identification of the risk analysis method 
We recommend that you identify the risk analysis method(s) you used to assess the risk 
profile, in general, as well as the specific devices 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.) 
 
Discussion of the device characteristics  
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.  
 
Description of the performance aspects 
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. 
 
  3 Contains Nonbinding Recommendations 
 
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.) 
 
Reliance on standards 
If you choose to rely on a recognized standard for any part of the device design or testing, 
you may include either a:  
  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 devices 
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. 
 
  4 Contains Nonbinding Recommendations 
 
 
4.  Scope 
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 devicessuch as reprocessed 
keratome bladeshave 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 devices 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.   
  5 Contains Nonbinding Recommendations 
 
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). 
 
  6 Contains Nonbinding Recommendations 
 
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. 
 
6.  Risks to Health  
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. 
 
 
Identified Risk  Recommended Mitigation Measures 
Inadequate Performance  Section 7. Preclinical assessment 
Section 8. Software assessment 
Section 12. Labeling 
Inflammation and Infection  Section 10. Material Characterization and 
(e.g., keratitis, epithelial  Biocompatibility  
ingrowth, debris in the 
interface)  Section 11. Validation of Cleaning and Sterilization 
Section 12. Labeling 
Electrical shock   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. 
  7 Contains Nonbinding Recommendations 
 
 
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.   
 
  8 Contains Nonbinding Recommendations 
 
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/cdrh/cfdocs/cfStandards/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. 
 
  9 Contains Nonbinding Recommendations 
 
Emissions 
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. 
 
Immunity 
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
  10 Contains Nonbinding Recommendations 
 
device with the same type and duration of patient contact, you may identify the predicate device 
in lieu of providing biocompatibility testing. 
 
11.  Sterilization 
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 devices 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. 
 
12.  Labeling 
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
 
Directions for use 
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 users 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. 
  11 Contains Nonbinding Recommendations 
 
 
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 users 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. 
  12 Contains Nonbinding Recommendations 
 
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 keratomes 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.   
 
1.  Dimensions 
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. 
 
2.  Materials 
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. 
 
3.  Hardness 
We recommend you compare the hardness of the blade and the OEM blade and 
indicate the test used to measure the hardness.   
 
  13 Contains Nonbinding Recommendations 
 
4.  Sharpness 
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. 
  14