The device consists of a pressurizing force control unit, tonometer tip (hereinafter referred to as measuring prism), section connected to a slit lamp microscope, and accessories. The measuring prism requires disinfection. The device includes no electrical elements. The device is set up to a dedicated support on the slit lamp, and used together with a commercially available slit lamp microscope. The pressurizing force control unit of the device incorporates a measurement dial that indicates pressurizing force, including a pressurizing force control knob, and a prism holder to mount the measuring prism. Also, the pressurizing force control unit includes a connector for a calibrator to check the pressurizing force of the device. The product is a manual medical device.

AI/ML Overview

This document (K182491 510(k) Summary) describes the Applanation Tonometer AT-2 and its substantial equivalence to the predicate device, Haag-Streit AT900. It does not contain information about a study proving the device meets acceptance criteria in the typical sense of a clinical trial or a machine learning performance study with a test set, training set, or ground truth established by experts.

Instead, the "acceptance criteria" here refer to technical specifications and performance characteristics, and the "study" is a performance test conducted according to an international standard.

Here's a breakdown of the requested information based on the provided text:

1. A table of acceptance criteria and the reported device performance

The document compares the new device (AT-2) to the predicate device (AT900) based on shared technical specifications. The "acceptance criteria" can be inferred to be alignment with these specifications, particularly the "Measurement accuracy" and "Repeatability" from the predicate.

Criteria	Predicate Device (Haag-Streit AT900)	New Device (Applanation Tonometer AT-2)	Acceptance Performance (AT-2)
Measurement Range	0 – 80mmHg	0 – 80mmHg	Met (same as predicate)
One scale unit	1.96mN	1.96mN	Met (same as predicate)
Measurement accuracy	$\pm$ 1.5 % of the nominal value or $\pm$ 0.49 mN, whichever is greater	(Not explicitly stated for AT-2, but performance testing according to ISO 8612:2009 implies meeting relevant standard thresholds)	Assumed to be met by ISO 8612 testing
Repeatability	$\leq$ 0.50mN	(Not explicitly stated for AT-2, but performance testing according to ISO 8612:2009 implies meeting relevant standard thresholds)	Assumed to be met by ISO 8612 testing
Reverse span	0.49mN	(Not explicitly stated for AT-2)	Assumed to be met by ISO 8612 testing
Applanation circle diameter	3.06mm	3.06mm $\pm$ 0.02mm	Met (within tolerance)
Applanation area	(Not specified for predicate)	7.354 mm³	(This is a design specification for the new device)

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

Not applicable. This is a medical device submission for a physical tonometer, not a study involving patient data or a test set in the context of an algorithm's performance. The "performance testing" refers to mechanical and physical characteristics of the device itself.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

Not applicable. There is no test set or ground truth established by experts in the context of clinical data for this type of device submission.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

Not applicable. No clinical test set or adjudication process is described.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

Not applicable. This device is not an AI-powered diagnostic tool, and no MRMC study of human readers is mentioned.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

Not applicable. This is a manual medical device with no standalone algorithm.

7. The type of ground truth used (expert concensus, pathology, outcomes data, etc)

Not applicable. The "ground truth" for this device's performance is tied to metrological standards for measurement accuracy and repeatability, as defined by ISO 8612:2009.

8. The sample size for the training set

Not applicable. This device does not use machine learning, so there is no training set.

9. How the ground truth for the training set was established

Not applicable. This device does not use machine learning, so there is no training set or ground truth established for it.

Summary of "Study" Information:

The "study" cited to demonstrate the device meets acceptance criteria is:

Performance Testing: "Performance of the Applanation Tonometer AT-2 was tested in accordance with ISO 8612:2009-Ophtalmic Instrument-Tonometers, Annex A.2."

This ISO standard outlines the requirements and test methods for applanation tonometers, ensuring they meet specified accuracy and repeatability thresholds. The success of this testing (implied by the conclusion of substantial equivalence) indicates the device's technical performance. No clinical data, patient studies, or expert evaluations of algorithm performance are described in this 510(k) summary.

Summary

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B-TQMS4101Letterhead Rev.1

Image /page/1/Picture/1 description: The image shows the logo for Takagi Seiko Co., LTD. The logo consists of a blue abstract symbol on the left, followed by the company name in a bold, sans-serif font. A horizontal line is placed beneath the company name, emphasizing the brand.

330-2 IWAFUNE, NAKANO-SHI, NAGANO-KEN, 383-8585, JAPAN TEL. +81-269-22-4512 FAX. +81-269-26-6321 URL: http://www.takagi-j.com E-mail: info@takagi-j.com

K182491

510(k) Summary

1. SUBMITTER

Company Name:	Takagi Seiko Co., Ltd.
Company Address:	330-2 Iwafune, Nakano-Shi, Nagano-Ken 383-8585 JAPAN
Telephone No:	+81-269-22-4511
Fax No:	+81-269-26-6321
Contact Person:	SHINYA KITAMURA
Title of Contact Person:	None
Telephone No:	+81-269-22-4511
Fax No:	+81-269-26-6321
Email Address:	kitamura.shinya@takagi-j.com
Date Prepared:	December 6, 2018

2. DEVICE

Name of Device:	Applanation Tonometer AT-2
Common Name:	Goldmann Tonometer
Classification Name:	Tonometer and Accessories
Regulation Number:	21 CFR 886.1930
Regulatory Class:	II
Product Code:	HKY

3. PREDICATE DEVICE

Name of Device:	Haag-Streit AT900
510(k) Number:	K981432
Common Name:	Goldmann Tonometer
Classification Name:	Tonometer and Accessories
Regulation Number:	21 CFR 886.1930
Regulatory Class:	II
Product Code:	HKY

4. REFERENCE DEVICE

Name of Device:	Applanation Tonometer AT-1
510(k) Number:	K172728
Common Name:	Goldmann Tonometer
Classification Name:	Tonometer and Accessories
Regulation Number:	21 CFR 886.1930

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Regulatory Class:	II
Product Code:	HKY

5. DEVICE DESCRIPTION

5.1 Device Identification

5.2 Principle Operation

a) Measurment Method

The Applanation Tonometer AT-2 is based on the physical law (Imbert-Fick Law) that states: the pressure in a sphere having an infinitely thin wall and containing fluid balances with the external force required for applanation of a certain (corneal) surface to a specified region of applanation based on the deformed shape of the cornea.

Specifically, the device measures the intraocular pressure based on the principle of Goldmann applanation tonometry by which the pressure required for applanation of a certain surface is measured. For measurement in a specified region of applanation in the case where the patient cornea has 3-diopter or greater corneal astigmatism, measurements in a specified region of applanation equivalent to a specified region of applanation without corneal astigmatism can be made by mounting with the angle on the angle scale inscribed on the measuring prism in alignment with the red line on the prism holder at the same angle of the amblyopic meridian of corneal astigmatism of the patient.

b) Device works

For the applanation Tonometer AT-2, the sterilized measuring prism is mounted on the prism holder of the tonometer, and after drops of topical anesthesia and fluorescein are placed in the eye of the patient, the measuring prism is brought into contact with the cornea. For accurate measurement of the applanation surface, the operator sets the slit lamp equipped with a blue filter to 10× magnification, illuminates the measuring prism with blue light, and observes the two fluorescent green semicircles (made by the two prisms included in the measuring prism). The pressure is adjusted by the pressurizing knob incorporated in the pressuring force control unit until both ends inside the two semicircles correspondence of both ends inside the two semicircles shows that the specified region of applanation is reached. The adjusted

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pressure is indicated by the pressurizing force indicating scale on the measurement drum incorporated in the device. The scale value indicated by the pressurizing force indicating scale on the measurement drum is read and the value multiplied by 10 is given in millimeter mercury (mmHg).

As the patient is seated, his or her intraocular pressure is measured on the slit lamp as part of regular examination within the range of conventional slit lamp examination.

5.3 Signal Processing

Relationship between the positions indicated on the measurement drum, force on the applanation surface, and pressure (Table 4.1.6)

Position of the	Force	Pressure
measurement drum	mN	kPa	mmHg
1	9.81	1.33	10
2	19.62	2.66	20
3	29.43	39.9	30
4	39.24	53.2	40
5	49.05	66.5	50
6	58.86	79.8	60
7	68.67	93.1	70
8	78.48	10.64	80

Table 4.1.6

5.4 Related accessories are as follows:

Calibrator: used to check the pressurizing force of the device

5.5 Device Characteristics

1. Patients-contacting material: PMMA.
1. The measuring prism is not sterilized when it is shipped and reusable; it must be cleaned and disinfected before the first use and between each use.

5.6 Environment of Use

3.6.1 Areas of application of the device

The Applanation Tonometer AT-2 is intended for use in medical offices, hospitals, and in optometrist and optician offices and clinics.

3.6.2 Ambient conditions

Temperature: +10℃ to +35℃

Air Pressure: 800hPa to 1060hPa

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Relative humidity: 30% to 75%

5.7 Method of Operation

In applanation tonometry the intraocular pressure is calculated from the force required to flatten a constant area of the cornea.

The operation principal based on Goldmann applanation method.

5.8 Materials of Use

General type of material used

The Applanation Tonometer AT-2 comes into contact with patients' corneal mucosal membrane surface, the material is acrylic resin and the contact time is limited exposure, respectively.

Other component parts of the device are made of general materials (example: stainless Steel,

copper alloy, and aluminum alloy).

5.9 Calibration

Pressure applied to the pressurizing arm is periodically checked by use of the calibrator during factory production/by users.

6. INDICATIONS FOR USE

The Applanation Tonometer AT-2 is intended to measure intraocular pressure for use as an aid in glaucoma screening and diagnosis.

7. COMPARISON OF TECHNOLOGICAL CHARACTERISTICS WITH THE PREDICATE DEVICE

7.1 Comparison of AT900 and AT-2

Table 1. Applanation Tonometer AT-2 vs. HAAG-STREIT Applanation Tonometer AT900

Comparison of Goldmann Tonometer Technical CharacteristicsApplanation Tonometer AT-1 vs. Haag-Streit AT900
Criteria	Predicate DeviceHaag-Streit AT900	New DeviceApplanation Tonometer AT-2
510(k) Number	K981432	K182491
Type	Manual contact Tonometer	Manual contact Tonometer
Indication	Intraocular Pressure(IOP) measurement	Intraocular Pressure(IOP) measurement
Design	Slit lamp mountedManual dial	Slit lamp mountedManual dial
Prism Material	PMMA	PMMA
Measurement Range	0 – 80mmHg	0 – 80mmHg
Measurement Method	Applanation	Applanation

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Measurementtechnique	Direct reading of IOP inmmHg (each division ondial of measuring drum isequal to 0.2gf (1.96mN))	Direct reading of IOP inmmHg (each division on dialof measuring drum is equal to0.2gf (1.96mN))
Applanation circlediameter	3.06mm	3.06mm
Calibration	Maintenance and calibrationrequired	Maintenance and calibrationrequired
Intended use	The Applanation Tonometer AT-2 is intended to measureintraocular pressure for use as an aid in glaucoma screeningand diagnosis.

7.2 Technical Specifications

Table 2. Applanation Tonometer AT-2 vs. HAAG-STREIT Applanation Tonometer AT900

ModelsItem	Predicate DeviceHaag-Streit AT900	New DeviceApplanation Tonometer AT-2
Measurement range	0-80mmHg
One scale unit	1.96mN
Measurement accuracy	$\pm$ 1.5 % of the nominal value or $\pm$ 0.49 mN, whichever is greater
Repeatability	$\leq$ 0.50mN
Reverse span	0.49mN
Applanation circle diameter		3.06mm $\pm$ 0.02mm
Applanation area		7.354 mm³
Dimensions (millimeter)	89(W) × 115(D)× 250(H)	207.6 (W)x84(D)x201(H)
Weight	0.5kg	0.81kg

8. PERFORMANCE AND SAFETY

6.1 Performance Testing

Performance of the Applanation Tonometer AT-2 was tested in accordance with ISO 8612:2009-Ophtalmic Instrument-Tonometers, Annex A.2.

8.2 Biocompatibility

The AT-2 is surface contacting device intended for limited contact with intact corneas. The device is intended for limited contact duration. The material composition and device manufacturing process are the same as those of the AT-1 prism cleared in K172728; therefore, new biocompatibility testing is not needed.

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8.3 Sterilization

The AT-2 is used non-srerile and sterilization is not applicable. AT-2 Prism and the AT-1 prism (K172728) are identical; therefore, new cleaning and disinfection validation is not needed.

8.4 Electrical safety and electromabnetic compatibility (EMC)

Electrical safety and EMC testing is not applicable. AT-2 does not contain electrical components.

8.5 Software

Software verification and validation is not applicable. AT-2 does not include software.

9. Conclusion

According to each evaluation result as mentioned above, the Applanation Tonometer AT-2 is substantially equivalent to the predicate device in safety, performance, specifications.

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Image /page/7/Picture/0 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the blue square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.

December 10, 2018

Takagi Seiko Co., Ltd. Shinya Kitamura Official Correspondent 330-2 Nakano-Shi Nagano-Ken 383-8585 Japan

Re: K182491

Trade/Device Name: Applanation tonometer AT-2 Regulation Number: 21 CFR 886.1930 Regulation Name: Tonometer And Accessories Regulatory Class: Class II Product Code: HKY Dated: September 10, 2018 Received: September 11, 2018

Dear Shinya Kitamura:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate 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) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

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Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801): medical device reporting (reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/CombinationProducts/GuidanceRegulatoryInformation/ucm597488.html; good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely yours,

for Malvina B. Eydelman, M.D. Director Division of Ophthalmic and Ear, Nose and Throat Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

Regulation Number and Section

§ 886.1930 Tonometer and accessories.

(a)
Identification. A tonometer and accessories is a manual device intended to measure intraocular pressure by applying a known force on the globe of the eye and measuring the amount of indentation produced (Schiotz type) or to measure intraocular tension by applanation (applying a small flat disk to the cornea). Accessories for the device may include a tonometer calibrator or a tonograph recording system. The device is intended for use in the diagnosis of glaucoma.(b)
Classification. Class II.