(81 days)
The Orbscan II Keratometer is intended to scan, map and display the geometry of the anterior segment of the eye.
The Orbscan II is a non-invasive, diagnostic system that measures and displays the anterior segment geometry of the eye. The system consists of an optical head, power supply and CPU. The optical head projects light through moving slit shaped apertures, The slit images are projected onto the eye at equi-distant angles from a central optical axis. A video camera placed on the optical axis records the images of the slits as they pass over the eye. The location of each slit at each position is determined during the system calibration.
During an examination, the slits are stepped across the cornea and an image of the cornea at each slit location is recorded, The CPU processes the images by using edge detection algorithms to determine the location of all of the edges the light strikes during the exam. Through direct triangulation, the elevation and curvature for the various surfaces is determined. Corneal thickness, anterior chamber depth and clevation of the iris and lens can then be determined by subtracting the surfaces.
This anterior segment information is displayed graphically to a user in the form of colored maps. These maps display variations in height and thickness numerically as well as with gradations in color. The graded colors allow for easier visualization of true measurements and how they relate to elevation and thickness of the eye geometry. The maps can be displayed individually or in several combinations. They can also be customized by the user for their specific examination needs. The Orbscan operates on a Windows™ based user interface and operating system that allows for ease of operation and system control. The CPU used with the Orbscan is a standard, high-speed PC type computer. Other peripherals may include a display monitor, a mouse pointing device and a printer for hard copies of the maps, should the user desire them.
To enhance repeatability, an optional placido pattern can be attached to the Orbscan. The placido pattern provides slope data for the anterior surface of the eye. The slope data obtained from using the placido pattern is combined with the elevation data as measured with triangulation. Tests on both test objects and human subjects have shown that the reproducibility has been enhanced from +/- . 005mm without the placido to +/-.003 mm with the placido pattern.
The device is non-invasive and only contacts the patient on his/her chin and forehead. The other concerns for safety are the light output and electrical safety. The light output is of an evesafe intensity and wavelength. Electrical safety is provided by packaging which is compliant to accepted safety standards, and mcdically safe power sources which isolate the patient from hazardous voltages and current.
The device is proven effective in incasuring the anterior geometry of the eve through internal company and independent clinical studies.
Here's an analysis of the Orbscan II Keratometer's acceptance criteria and the study reported to show it meets those criteria, based on the provided document:
Orbscan IITM Keratometer Performance Study Analysis (K984443)
1. Acceptance Criteria and Reported Device Performance
The primary performance metric highlighted and improved upon for the Orbscan II is its reproducibility.
| Acceptance Criteria / Performance Metric | Predicate Device Performance (Orbscan) | Orbscan II Reported Performance | Notes |
|---|---|---|---|
| Reproducibility | +/- 0.025 mm | +/- 0.003 mm | The improved reproducibility of +/- 0.003 mm is achieved with the optional placido pattern attached. Without the placido, the reproducibility is stated as +/- 0.005mm. The predicate device's figure is likely without a placido equivalent. |
| Field of view | 10 x 14 mm | Same | No change noted. |
| Axis range | 0 to 360 degrees | Same | No change noted. |
| Dioptric range | 9 to 99 Diopters | Same | No change noted. |
| Resolution | 0.10 Diopters | Same | No change noted. |
| Processing Time | ~3-5 min (anterior corneal surface) | < 1.5 min (all information) | Not explicitly an "acceptance criterion" but a significant performance improvement due to increased CPU capability. |
The acceptance criterion, though not explicitly stated as a numerical 'pass/fail' threshold, is implicitly defined by demonstrating a significant improvement in reproducibility over the predicate device, specifically achieving +/- 0.003 mm with the placido pattern.
2. Sample Size Used for the Test Set and Data Provenance
The document states: "Tests on both test objects and human subjects have shown that the reproducibility has been enhanced from +/- . 005mm without the placido to +/-.003 mm with the placido pattern."
- Sample Size (Test Set): The exact number of "test objects" and "human subjects" used is not specified in the provided summary.
- Data Provenance: The document does not specify the country of origin. It indicates that the studies were "internal company and independent clinical studies," implying a mix of sources. It is likely retrospective or prospective depending on the nature of the "internal company" versus "independent clinical studies," but this is not explicitly stated for the reproducibility data itself.
3. Number of Experts Used to Establish Ground Truth and Qualifications
The document does not provide information on the number or qualifications of experts used to establish ground truth for the test set.
4. Adjudication Method for the Test Set
The document does not specify any adjudication method (e.g., 2+1, 3+1, none) for the test set. Given the nature of reproducibility measurements (instrument measuring the same object multiple times), traditional expert adjudication for clinical agreement might not be applicable in the same way as for diagnostic interpretation.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
There is no mention of a Multi-Reader Multi-Case (MRMC) comparative effectiveness study being performed. The device is for measurement and display of geometry, not for interpretation by multiple human readers in a diagnostic context that would typically warrant an MRMC study related to interpretation improvement.
6. Standalone (Algorithm Only) Performance
The primary performance metric (reproducibility) implicitly describes the standalone performance of the algorithm and the device system. The device captures data and processes it using "edge detection algorithms" and "direct triangulation" to determine measurements. The reproducibility figures reflect the consistency of these automated measurements. The improved processing time (less than 1.5 min) also relates to the standalone performance of the algorithm and integrated system.
7. Type of Ground Truth Used
The ground truth for the reproducibility study would be the physical dimensions and geometry of the "test objects" or the "true" anterior segment geometry of the human subjects. This would typically be established through highly accurate, independent measurement methods, though these specific methods are not detailed. For human subjects, repeated measurements over a short period with minimal physiological change serve as the basis for assessing instrument reproducibility.
8. Sample Size for the Training Set
The document does not specify a sample size for any training set. It mentions "edge detection algorithms" and "direct triangulation," which are often based on well-established mathematical principles and might not involve a machine learning "training set" in the modern sense. If any training was involved for internal algorithm development, it is not disclosed.
9. How Ground Truth for the Training Set Was Established
As no training set is explicitly mentioned, the method for establishing its ground truth is also not described. For rule-based algorithms, ground truth might be implicitly built into the mathematical models rather than established through labeled datasets.
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3/5/99
Summary of Safety and Efficacy
| Date of Summary | March 3, 1999 |
|---|---|
| Sponsor | Orbtek, Inc.1977 W. North TempleSalt Lake City, UT 84106, USA801-320-9700 |
| Contact Person | Pier CalacinoQuality Assurance Manager |
| Name of Device | Orbscan IITM Keratometer |
| Class | Class II |
| Classification Name | AC Powered KeratoscopeAC Powered SlitLamp Biomicroscope (886.1850) |
| Product Code | MXK Anterior Segment Analysis Device |
| Predicate Device | The predicate device is the original Orbscan manufacturedby Orbtek, Inc., and cleared for marketing by FDA on07/06/94 with premarket notification number K940647. |
| Intended Use | The Orbscan II Keratometer is intended to scan, map anddisplay the geometry of the anterior segment of the eye. |
Device Description
The Orbscan II is a non-invasive, diagnostic system that measures and displays the anterior segment geometry of the eye. The system consists of an optical head, power supply and CPU. The optical head projects light through moving slit shaped apertures, The slit images are projected onto the eye at equi-distant angles from a central optical axis. A video camera placed on the optical axis records the images of the slits as they pass over the eye. The location of each slit at each position is determined during the system calibration.
During an examination, the slits are stepped across the cornea and an image of the cornea at each slit location is recorded, The CPU processes the images by using edge detection algorithms to determine the location of all of the edges the light strikes during the exam. Through direct triangulation, the elevation and curvature for the various surfaces is determined. Corneal thickness, anterior chamber depth and clevation of the iris and lens can then be determined by subtracting the surfaces.
This anterior segment information is displayed graphically to a user in the form of colored maps. These maps display variations in height and thickness numerically as well as with gradations in color. The graded colors allow for easier visualization of true
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measurements and how they relate to elevation and thickness of the eye geometry. The maps can be displayed individually or in several combinations. They can also be customized by the user for their specific examination needs. The Orbscan operates on a Windows™ based user interface and operating system that allows for ease of operation and system control. The CPU used with the Orbscan is a standard, high-speed PC type computer. Other peripherals may include a display monitor, a mouse pointing device and a printer for hard copies of the maps, should the user desire them.
To enhance repeatability, an optional placido pattern can be attached to the Orbscan. The placido pattern provides slope data for the anterior surface of the eye. The slope data obtained from using the placido pattern is combined with the elevation data as measured with triangulation. Tests on both test objects and human subjects have shown that the reproducibility has been enhanced from +/- . 005mm without the placido to +/-.003 mm with the placido pattern.
The device is non-invasive and only contacts the patient on his/her chin and forehead. The other concerns for safety are the light output and electrical safety. The light output is of an evesafe intensity and wavelength. Electrical safety is provided by packaging which is compliant to accepted safety standards, and mcdically safe power sources which isolate the patient from hazardous voltages and current.
The device is proven effective in incasuring the anterior geometry of the eve through internal company and independent clinical studies.
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Product Comparison
| Feature | Orbscan | Orbscan II |
|---|---|---|
| Field of view | 10 x 14 mm | same |
| Axis range | 0 to 360 degrees | same |
| Dioptric range | 9 to 99 Diopters | same |
| Resolution | 0.10 Diopters | same |
| Reproducibility | +/- 0.025 mm | +/- 0.003 mm1 |
| Acquisition head | scanning slitHiRes video CCD cameraFully coated opticsCoaxially fixation lightOptical Positioning Aid | same |
| Additional Hardware | Backlit placido pattern2Relocation of Power supply to Selfcontained box3 | |
| Power Requirements | 110/120 volt AC, 50/60 Hz220/240 volt AC, 50/60 Hz | same |
| Dimensions | 24" x 34" footprint | same |
| Cpu4 | 80486 33 MHz4 Mb Ram | Intel Pentium technology400 MHz or greatertyp 128Mb Ram |
1 Surfaccs measured with Placido pattern attached.
2 The Placido Pattern provides slope data, which, when integrated with true elevation data yields better surface curvature calculations. The pattern is back illuminated with highly diffused LED light sources and is attached to the front of the Orbscan II without modification. The pattern does not come in contact with the patient and is electrically isolated for safety.
3 The power supply was originally located in the cabinet that contained the CPU. The previous location was determined to not be as safe due to the fact that computer housings are frequently accessed by nontechnical individuals. The new location allows more room for a medically approved power supply and it isolates the device from uncontrolled grounding. This arrangement also prevents un-authorized access to the device.
4 Increased computing capability allowed the ability to process the increased amount of data points. Orbscan took approximately 3-5 min to process the anterior corneal surface only. Orbscan II processes all information in less than 1 1/2 min.
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Anterior surface topography Posterior Surface topography Full Corneal Pachymetry Elevation of the iris Elevation of the Lens Depth of the Anterior Chamber
S The term Topography is used to include the two terms of Elevation and curvature.
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Image /page/4/Picture/1 description: The image is a black and white logo for the U.S. Department of Health & Human Services. The logo features a stylized graphic of three human profiles facing right, stacked on top of each other. The profiles are simple and abstract, with flowing lines suggesting hair or movement. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular pattern around the graphic.
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
MAR - 5 1999
Mr. Pier Calacino Quality Assurance Manager ORBTEK, Inc. 1977 West North Temple Salt Lake City, UT 84116
Re: K984443
Trade Name: AC-powered Slitlamp Biomicroscope Regulatory Class: II Product Code: MXK Dated: January 22, 1999 Received: January 25, 1999
Dear Mr. Calacino:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic OS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.
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Page 2 - Mr. Pier Calacino
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4613. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html".
Sincerely yours,
A. Ralph Rosenthal
A. Ralph Rosenthal, M.D. Director Division of Ophthalmic Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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Page 1 of 1
510(k) Number (if known): __ K984443__________________________________________________________________________________________________________________________________________
Device Name:
Indications For Use:
The Orbscan II intended use is for scanning, mapping and displaying the geometry of the anterior segment of the eye.
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
Carl Callaway
(Division Sign-Off)
Division of Ophthalmic Devices
510(k) Number. K984443
Prescription Use (Per 21 CFR 801.109) OR
Over-The-Counter Use__________________________________________________________________________________________________________________________________________________________
(Optional Format 1-2-96)
§ 886.1850 AC-powered slitlamp biomicroscope.
(a)
Identification. An AC-powered slitlamp biomicroscope is an AC-powered device that is a microscope intended for use in eye examination that projects into a patient's eye through a control diaphragm a thin, intense beam of light.(b)
Classification. Class II (special controls). The device, when it is intended only for the visual examination of the anterior segment of the eye, is classified as Group 1 per FDA-recognized consensus standard ANSI Z80.36, does not provide any quantitative output, and is not intended for screening or automated diagnostic indications, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 886.9.