Falck Medical, INC, an FDA registered corporation, is a leading developer of innovative technologies with applications in the diagnosis and treatment of ischemic retinopathies, age related retinopathies and glaucoma. All of the technologies are covered by multiple national/international patents and patent pending applications.

To learn more about these innovative technologies please contact us.

"Deus ex Machina"

 

 

FAT1 Multifunction Device:

 

Falck Medical Multifunction Device  – FAT1TM
                         The New Standard
Slit Lamp Mounted, Cleared by the FDA for Tonometry, Ocular Pulse Amplitude, Tonography, and Ophthalmodynamometry Measurement.


1. Tonometry - IOP Measurement

  • Touch Screen User Input

  • Applanation Method

  • No fluorescein, No Subjective Mire Alignment

  • 60 Automated Measurements in 3 Seconds

  • Measures Variation of IOP with Cardiac Cycle – True IOP

  • Corneal Resistance and Wetness Compensation

2. Ocular Pulse Amplitude Measurement

  • Variation in IOP that Occurs with Blood Flow

  • Systolic and Diastolic Waveform Recorded and Displayed

3. Tonography Measurement

  •  Measures Outflow of Aqueous Humor

  • Decreased Outflow in Glaucoma

  • Therapy is Directed at Increasing Outflow to Lower IOP

  • Outflow Measurement Useful for Glaucoma Management

4. Ophthalmodynamometry Measurement

  • Pulsatile Force of Central Retinal Artery

  • Central Retinal Artery Pressure Decreased in Vascular Disease

  • Estimate Ocular Perfusion Pressure, Important in Glaucoma Management

5. Single Use Disposable Prism

  • Effectively Blocks Transmission of Infectious Disease

  • Eliminates Risk of Transmission

6. Electronic Data Storage

  • USB Flash Drive

  • Numeric File

  • Excel Format

7. Data Display

  • Average Value with Percent Variation

  • Multiple Data Points within each Measurement Analyzed for Repeatability and Accuracy

Raise Your Standard of Care, Eliminate Infection Risk, Enhance Your Practice

FAT1 Technology Overview
https://www.youtube.com/watch?v=n0jWmC9Fky4&feature=youtu.be 

FAT1 Device User Manual
fat1-user-guide.pdf

Falck Medical FAT1 Instructional Video
https://www.youtube.com/watch?v=B_bd8yWkMB0&feature=youtu.be 

Pearls for Using the FMAT1 Device from Falck Medical Inc
https://www.youtube.com/watch?v=UFqVhEBs1Ow

Proper Insertion of Fixed-Use Prism for Falck Medical FAT1 Device
https://www.youtube.com/watch?v=NQZnYK6BJSk&feature=youtu.be 

Introduction to the Falck Medical, Inc FMAT1 Multifunction Device.
https://www.youtube.com/watch?v=8bH3PwI15jg&feature=youtu.be

Falck Medical, Inc., FMAT1 Serial Tonometry Measurement.
https://www.youtube.com/watch?v=GgM6GlEJOxU&feature=youtu.be
 

Falck Medical, Inc., FMAT1 Tonography Measurement.
https://www.youtube.com/watch?v=VNhWci4RrYY&feature=youtu.be
 

Falck Medical, Inc., FMAT1 Ophthalmodynamometry Measurement.
https://www.youtube.com/watch?v=R3ZlwK2x73w&feature=youtu.be

Falck Medical, Inc., FMAT1 Coding and Reimbursement
https://www.youtube.com/watch?v=3yk25a7BQeo&feature=youtu.be

Falck Medical Multi-Function DEVICE Powerpoint

Press Conference for the Falck Medical Inc. FMAT1 Device at the Boston AAO 2021 Meeting


Clinical and Laboratory Trials Summary:

Tonometry Study Summary:

In a clinical trial comparing of the Falck Medical Multifunction Device  (FAT1) in 205 eyes
the following results were obtained:

  • No statistical relationship found between FAT1 readings and corneal curvature or thickness, r2 < 0.05.

Manometric Study Summary:

In a comparative study of the FAT1 readings to a reference u-tube mercury manometer using human eye bank eyes, the following results were obtained:

  • Average Coefficient of Variation: 2.6% +/- 0.10 (5 to 50mmHg).
     

  • Average Standard Deviation: 0.7 mmHg +/- 0.4 (5 to 50mmHg).

Clinical Tonography Trial Summary:

In a clinical trial comparing the FAT1 to a reference indentation tonographer for the measurement of conventional outflow facility in 91 eyes from 91 subjects the following results were obtained:

  • The mean conventional outflow facility (C) difference between the FAT1 and the reference Indentation Tonographer over a range of 0.01 to 0.70 ul/min/mmHg was 0.0043 ul/min/mmHg ( 95% CI, 0.001 to 0.0076 ), n= 182.
     

  • Average FAT1 conventional outflow facility measurement in the glaucoma group was 0.09 +/- 0.05 and in the non-glaucoma group was 0.31 +/- 0.12 ul/min/mmHg, p < 0.0001, n = 182.
     

  • Average FAT1 IOP measurement in the glaucoma group was 20.02 +/- 5.5 and in the non-glaucoma group was 18.6 +/- 2.4, p = 0.01, n = 182.
     

  • In the High outflow facility group (C > 0.18) (non-glaucoma, 28/30 eyes) 93.3% of the paired differences were within +/- 1.96 standard deviations of the mean difference between the FAT1 and the reference Indentation Tonographer, n=60.
     

  • In the Medium outflow facility group (C >0.09 < 0.18) (glaucoma, 29/31 eyes) 95.2% of the paired differences were within +/- 1.96 standard deviations of the mean difference, n=62.
     

  • In the Low outflow facility group (C < 0.09) (glaucoma, 30/30 eyes) 96.7% of the paired differences were within +/- 1.96 standard deviations of the mean difference, n=60.

Tonographic Laboratory Study Summary:

In a comparative tonographic laboratory study using freshly enucleated preserved eye bank eyes, the following results were obtained:

  • For every 10 mmHg change in IOP average anterior chamber fluid volume change was 3.22 ul/minute, for a 20 mmHg change in IOP average anterior fluid volume change was 7.027 ul/minute and for 30 mmHg change in IOP average anterior fluid volume change was 11.75 ul/minute, r2 = 0.99.
     

  • The correlation coefficient for volume decrease and corneal indentation was 0.999.
     

  • The correlation coefficient for volume decrease and applanation diameter was 0.997.

Clinical Ophthalmodynamometry (OPH) Study Summary:

In a clinical trial involving 42 adult eyes where ipsi-lateral OPH force, brachial artery blood pressure and IOP were recorded, the following results were obtained:

  • The average OPH estimated Central Retinal Artery Force was 59.73 +/- 11.10 mmHg.
     

  • The Mean Brachial Artery Blood Pressure (MBAP) was 93.16 +/- 8.32 mmHg.
     

  • The average IOP was 15.72 +/- 3.04 mmHg.
     

  • The average calculated Ocular Perfusion Pressure was 44.01 mmHg.

    *Results on file with the Food and Drug Administration


News:

New Multifunction Applanation Device Which Can Be Used as a Risk Assessment Tool in the Management of Glaucoma and Vascular Disorders  Published in CFOCEO Magazine on 03/21/2016. Click on this link to read full text of the interview.

The FAT1 device was cleared by the Food and Drug Administration on 01/15/2016 for market introduction with the following indications for use: Tonometry, Ocular Pulse Amplitude, Tonography and Ophthalmodynamometry
 



Case Studies:

 Branch Vein Occlusion

An 82 year old male presented with a history of Branch Retinal Vein Occlusion in the supero-temporal quadrant of his left eye. On examination arteriolar narrowing and arterio-venous compression was noted. The OCT image demonstrates thinning and loss of normal architecture in the supero-temporal quadrant. Mean Central Retinal Artery Pressure (MCRAP) and Ocular Perfusion Pressure (OPP) were measured using the Ophthalmodynamometry Function of the FAT1 Device.

With normal vascular physiology and normal vessels, in the upright position MCRAP should be equal to or greater than 60 % of ipsi-lateral Mean Arterial Brachial Blood Pressure (MABBP). Ocular Perfusion Pressure (OPP) is the difference between MCRAP and IOP. Ocular Perfusion Pressure is the net force that drives blood flow into the eye (Adlers Physiology of the Eye, Clinical Application, Tenth Edition, Chapter 33, Ocular Circulation, page 764-765).

The measured ipsi-lateral MABBP was 106 mmHg, 60% of this value is 60.6 mmHg. The FAT1 measured MCRAP was 52.8 mmHg which is less than expected and the OPP was 36.2 mmHg which is also less than expected. See FAT1 Ophthalmodynamometry Result Screen. In the FAT1 Ophthalmodynamometry study, in healthy eyes the Average Ocular Perfusion Pressure was 44.01 mmHg.      Both values are less than expected, documenting decreased retinal perfusion from the BRVO and atherosclerosis.

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Click to Enlarge and to Close


Amaurosis Fugax , Carotid Atherosclerosis

An 80 year old male presented with an episode of temporary vision loss in his right eye one week ago. No plaque or other emboli were found on examination. Using the Ophthalmodynamometry Function of the FAT1 Device, Mean Central Retinal Artery Pressure (MCRAP) and Ocular Perfusion Pressure (OPP) were measured.

Measured Mean Ipsilateral Arterial Brachial Blood Pressure (MABBP) was 89.3 mmHg. Sixty percent of this value is 53.6 mmHg. Measured Mean Central Retinal Artery Pressure (MCRAP) was less than expected at 44.9 mmHg. Ocular Perfusion Pressure (OPP) was also less than expected at 32.1 mmHg. See the FAT1 Ophthalmodynamometry Result Screen.

Because the history and the FAT1 results were suggestive of carotid vascular disease, an intracranial Magnetic Resonance Imaging Arteriogram was performed which confirmed atherosclerotic carotid vascular disease and raised the possibility of an anterior communicating artery aneurysm. See the MRA report. A CTA was scheduled for further evaluation.   

The CTA confirmed an anterior communicating artery aneurysm.

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Click to Enlarge and to Close


Pigmentary Glaucoma

An 57 year old male with Pigmentary Glaucoma in the right eye presented with  elevated Intraocular Pressure (IOP). Current medications were Combigan BID, Pilocarpine 1% TID, Travatan QHS and Diamox 500 mg BID. On gonioscopy the angle was open with 4+ pigment. Laser Trabeculoplasty was performed. The IOP remained elevated at 30 mmHg well above the target value. Heidelberg Retinal Tomography documented progressive thinning of the nerve fiber layer at 6 and 12 o’clock. See the HRT results.

The Tonography Function of the FAT1 Device was used to assess Trabecular Meshwork Aqueous Humor Outflow. Aqueous Humor Outflow was reduced at 0.109 microliters / minute and the ratio of the IOP (Po) to Outflow (C), Po / C Ratio, was 204.6. See FAT1 Tonography Results Screen.    

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Click to Enlarge and to Close

In the FAT1 Tonography Clinical Study, Glaucomatous eyes had an Outflow Value less than 0.18 microliters / minute. A Po / C ratio greater than 100 is characteristic of glaucomatous eyes (Chandler and Grants Glaucoma, Fourth Edition, Chapter 6, Tonometry and Tonography, page 45 - 48).

Visual field testing was performed. The decreased outflow facility, which did not respond to medical or laser surgery, was the cause of the elevated IOP. The patient underwent a trabeculectomy to bypass the dysfunctional trabecular meshwork.

The Tonography function of the FAT1 device was used to assess aqueous humor outflow after the trabeculectomy procedure. Outflow was increased to 0.745 microliters / minute, confirming the effectiveness of the trabeculectomy. See the post-trabeculectomy procedure FAT1 Tonography Results Screen.   


Angle Closure / Pupillary Block

A 67 year old male presented with an intumescent count fingers cataract in the right eye. Pupillary block was present. On direct gonioscopic examination the anterior chamber angle was closed at Grade 1. In the left eye and the anterior chamber angle was open at Grade 4.

The Tonography function of the FAT1 device was used to assess aqueous humor outflow through the trabecular meshwork. It was reduced to 0.044 microliters / minute and the Po / C ratio was increased at 327.3. See the FAT1 Tonography Results Screen for the Right Eye.



In the left eye, the aqueous humor outflow was 0.203 microliters / minute and the Po / C ratio was 88.7. See the FAT1 Tonography Results Screen for the left eye.



One percent Pilocarpine was placed in the right eye and a YAG Laser Peripheral Iridectomy was performed. The pupillary block decreased and the anterior chamber angle deepened to Grade 3.

Aqueous humor outflow was assessed post-iridectomy using the Tonography Function of the FAT1 Device. It increased to 0.374 microliters / minute, confirming the effectiveness of the iridectomy. See the post-iridectomy FAT1 Tonography Results Screen.


Publications

Bonus Feature Modern Optometry October 2021. A New Glaucoma Management Tool Measures What Eye Care Providers Strive to Improve. Click On Title Too Read Full Text.


Association for Research and Vision in Ophthalmology April 2nd, 2010.  

Abstract Title: The Effect of Intraocular anti-VEGF Injections on Ocular Perfusion Pressure.

Authors: Elias Reichel, Heeral Shah, Tufts University New England Eye Center

Keywords: Age Related Macular Degeneration, anti-VEGF, Ocular Perfusion Pressure, Intraocular Pressure.

Purpose: Blood flow into the eye is determined by the ocular perfusion pressure (OPP). OPP is the difference between the mean central artery pressure (MCRAP) and the intraocular pressure (IOP),(OPP = MCRAP – IOP).1 Intraocular anti-VEGF injections can raise intraocular pressure and decrease retinal blood flow.2 The aim of this study was to investigate the effect that intraocular anti-VEGF injections have on ocular perfusion pressure.

Methods: The OPP, MCRAP, IOP and Ocular Pulse Amplitude (OPA) was measured using the Falck Medical Multifunction Applanation Tonometer (FAT1) in twenty eyes of twenty patients immediately pre and post anti-VEGF injection. The mean upright ipsilateral brachial blood pressure (MBBP) was also recorded. The independent-samples t-test was used to analyze the pre and post injection differences. Twelve eyes received Avastin and eight eyes Lucentis. All eyes received 0.5mg.

Results: The cohort mean age and MBBP was 75.1+/- 19 years and 93.45 +/-11 mmHg. The mean decrease in MCRAP post-injection was 10.3 mmHg, p = 0.03 (45–34.7). The mean increase in IOP post-injection was 10.8 mmHg, p = 0.0002 (28.5–17.7). The mean decrease in OPP post-injection was 11.9 mmHg, p = 0.003 (27.3-15.4).  The mean decrease in OPA post-injection was 0.5 mmHg, p = 0.03 (2.3-1.8). In twelve eyes the post-injection OPP decreased due to both an increase in IOP and a decrease in MCRAP.  In two eyes the post injection OPP decreased to zero from both an increase in IOP and a decrease in MCRAP. 

1 Kaufman PL, Alm A. Adlers Physiology of the Eye. Tenth Edition 2003;764-67.

2 Papadopoulou DN, Medrinos E, Mangioris G, et al. Intravitreal ranibizumab may induce retinal arteriolar vasoconstriction in patients with neovascular age-related macular degeneration. Ophthalmology.2009;116:1755-61.

c


Clinical and Manometric Comparison of The Falck Autotonometer and The Goldmann Tonometer. Association for Research in Vision and Ophthalmology, April 27th, 2008. F. Y. Falck, R. Falck.; University of Connecticut School of Medicine, Farmington, CT.

Purpose: In recent clinical studies the Goldmann tonometer has been found to lack accuracy where the corneal thickness varies from the calibration standard of 0.5 mm (1). If the corneal thickness is less then 0.5 mm the intraocular pressure will be underestimated possibly leading to a false negative diagnostic impression and if the corneal thickness is greater then 0.5 mm the intraocular pressure will be overestimated possibly leading to a false positive diagnostic interpretation. The greater the deviation of thickness from the mean the greater the over or underestimation of intraocular pressure (2).  Corneal curvature may also effect the accuracy of the Goldmann. The smaller the corneal radius the greater the resistance to flattening. Thus, steeper corneas may lead to an overestimation of intraocular pressure with the Goldmann and flatter corneas may lead to an underestimation (3).

 

Additionally, there are also concerns about transmission of infectious agents with reusable applanation tonometry prisms or tips (4).

 

The Autotonometer is an automated electro-optical microprocessor driven tonometer that performs multiple applanations in an average measurement time of 0.5 seconds. The eye pressure is digitally displayed and retained in memory for recall. The device compensates for corneal thickness and curvature and can be used portably or on the slit-lamp microscope. A small plastic disposable applanation prism prevents spread of infection. Fluorescein is not required.

This study was undertaken to determine the accuracy of the Autotonometer manometrically and clinically as compared to the Goldmannn tonometer.

Methods: Eye bank eyes were pressurized using saline to a known value in a range of 5 to 60 mmHg with a digital manometer (Bio-Tek Instruments, INC., Winooski, VT.). Calibration of the digital manometer was verified with a u-tube mercury manometer. The Autotonometer applanation force was then recorded at 5 mmHg intervals from 5 to 45 mmHg. Multiple readings at each point were obtained.

In the clinical comparison trials 95 eyes were enrolled. The intraocular pressure was measured in an alternating sequence of the Goldmann followed by recording the Autotonometer applanation force and then in reverse for the next study eye.

Linear regression analysis was performed.

Results: In the manometric eye bank studies a perfect correlation (r = 0.99, y = - 0.51 + 0.3 x) was found with the Autotonometer over an intraocular pressure range of 5 to 45 mmHg (Figure 1). In the comparison clinical trials the correlation between the

Autotonometer and the Goldmann tonometer was 0.88 (y = - 6.79 + 0.73 x) over a range of 8 to 62 mmHg (Figure 2).

Figure 1: Autotonometer Manometric Eye Bank Experiment

Figure 2: Clinical Comparison of Autotonometer and The Goldmann Tonometer

Conclusions: The Autotonometer produced accurate and repeatable applanation force measurements that correlated in a perfect linear relationship with manometric intraocular pressure. Additionally, a strong correlation was found with Goldmann estimates of eye pressure. Some of the variability found between the Goldmann and the Autotonometer is most likely related to the subjective measurement error associated with the Goldmann. The Autotonometer is objective and requires minimal operator skill. Other probable sources of variability would be variations in corneal thickness and curvature in the clinical study eyes. The Autotonometer compensates for the effect of corneal thickness and curvature while the Goldmann tonometer does not. Additional clinical and laboratory studies are ongoing.

References:

1.      Goldmann H, Schmidt T. Uber Applanationstonometrie.    

Ophthalmologie 1957;134:221-42.                                     

 2.      Shah S, Chatterjee A, Mathai M, et al. Relationship between Corneal  Thickness and Measured Intraocular Pressure in a General Ophthalmology Clinic. Ophthalmology 1999;106:2154-2160.

3.      Woo S, Kobayashi A, Lawrence C, et al. Mathematical Model of the

Corneo-Scleral Shell As Applied to Intraocular Pressure-Volume Relations and Applanation Tonometry. Ann Biomed Eng 1972;1:87-98.

4.      CDC. Recommendations for Preventing Possible Transmission of  Human T-Lymphotrophic Virus Type 3/Lymphadenopathy- Associated Virus from Tears. MMWR 1985;34:533-534.                       

CR:P


Agency for Healthcare Research and Quality: Comparative Effectiveness of Screening for Glaucoma. January 10, 2011.

Clinical Comparison of FAT1 and Goldmann Applanation Tonometer.

Introduction:

The Falck Medical Multifunction Device (FAT1) measures intraocular pressure (IOP) using the same method of applanation (Imbert-Fick Law) as the Goldmann Applanation Tonometer (GAT). The GAT IOP measurement does not correct for the variation in corneal biomechanics or for the variation of IOP with the cardiac cycle. The pulsating mires of the GAT are evidence of the increase in IOP during systole.1 The FAT1 measurement corrects for the variation in corneal biomechanics and measures the variation of IOP with the cardiac cycle.

The GAT takes only one subjective user dependent measurement. So, it is not possible to know the accuracy and precision of the measurement.1 The FAT1 captures a measurement every 7 milliseconds over multiple cardiac cycles. The measurement is objective, no mire alignment and user independent. Measurement data captured by the FAT1 is statistically analyzed for precision and accuracy. The Mean IOP, % Variation, the IOP Variation with the Cardiac Cycle (OPA) and the Number of IOP Measurements Captured (N) are displayed. The data is saved to a secure electronic file.2

The GAT prism cannot be sterilized and therefore there is a risk of transmission of infectious disease agents that are present in the tears.1 The FAT1 has a fixed used disposable prism that blocks infectious disease transmission.2

The FAT1 Device also measures Conventional Outflow Facility (Tonography).2 Impaired outflow is the primary cause of glaucoma.3

The FAT1 also measures Mean Central Retinal Artery Pressure (MCRAP) (Ophthalmodynamometry).2 MCRAP and IOP is used to calculate Ocular Perfusion Pressure (OPP) (OPP = MCRAP – IOP). OPP is the net force that drives blood flow into the eye.4

The purpose of the FDA Clinical Study was to evaluate the precision and accuracy of the FAT1 IOP measurement as compared to the GAT.

Methods:

The FAT1 device clinical study was a single site investigator study with external auditing oversight by the United States Food and Drug Administration (FDA) and an Independent Contract Review Organization (CRO). Data analysis was provided by the CRO and the FDA. One hundred twenty-five subjects and 209 eyes were coded by numeric ID and entered into a secure electronic data base for final analysis. The FAT1 was connected directly to the electronic data base. Measurement data from the FAT1 electronically went directly into each subject file. Data from the GAT, pachymetry and keratometry measurements were manually entered. Sixty-one eyes underwent pachymetry and keratometry measurements.  

The measurement sequence was randomized with the first ten eyes measured by the FAT1 first and the next ten eyes measured by the GAT first. This randomization sequence was maintained throughout the study. Two FAT1 devices (FAT1A and FAT1B) were used in the study. All study data went directly into an electronic study file. Once entered the data was secure and could not be changed.

The FAT1 device automatically calibrates before any measurement. The GAT was manually calibrated before each measurement.

The study subject age range was 24 to 94 years. One-third of study eyes were either ocular hypertensive or had glaucoma. The study was carried out in accordance with the FDA Guidance for Tonometers, as published March 27th, 2006.

Subjects were screened for established inclusion and exclusion criteria. If found eligible, each study subject signed an informed consent document prior to participation. The study was designed as a one-time exposure to the FAT1 and GAT. All measurements were taken by two ophthalmic technicians who were trained in the use of the FAT1 and the GAT. The clinical study was conducted in accordance with the abbreviated rules for investigational device exemptions within the meaning of 21 CFR Part 812.2(b) and for the rights and protections of investigational subjects in accordance with 21 CFR Part 50 – Informed Consent; and 21 CFR Part 56 – Institutional Review Board Regulations. Full approval to conduct the study was awarded on November 1, 2006.   

Study Subject Characteristics:

One hundred twenty-five subjects (209 eyes) were enrolled. Overall accountability at the end of the study was 100%. There were no withdrawals. One hundred forty-eight eyes were considered normal, and 61 eyes were considered ocular hypertensive or glaucomatous. In normal subjects the range of IOP was 9 to 21 mmHg. In glaucoma subjects the range of IOP was 10 to 56 mmHg. The overall age range was 24 to 94 years. There were 71 males and 54 males enrolled in the study.  

Adverse Events:

No adverse events were reported during the course of the clinical study.

Safety:

The results of all study subjects were considered for the safety evaluation. No complications were reported during the clinical study.

Incident Report:

During the clinical study, one subject was found to have a large disparity of Mean Central Retinal Artery Pressure (MCRAP) between the two eyes. MCRAP was reduced in the left eye. The disparity led the principal investigator to refer the subject for emergency admission to the local medical facility. Diagnostic imaging confirmed the presence of an internal carotid artery aneurysm on the left side.  The subject was treated and is doing well. This is not considered an adverse event. Enrollment in the study likely saved the subjects life. The subject was excluded from the data analysis.

Results:

See Scatter Plot Figure 1A. The FAT1 measured IOP value is plotted on the x-axis and the GAT IOP on the y-axis. The regression line, the equation and the r-squared value is displayed. The maximum r-squared value is 1. The higher the number, the greater the strength of the relationship. The r-squared value is 0.925.

See Bland – Altmann Plot Figure 2A. The paired difference between the reference GAT and the FAT1 is plotted on the y-axis and the mean of the GAT and FAT1 is plotted on the x-axis. The mean and + / - 1.96 standard deviation is displayed. The average mean difference is 0.7 mmHg.

See Table 1 – Number and Percent of Paired Differences That Exceed Tolerance by each Pressure range

A tabulation of the number of eyes and percent of paired differences (GAT – FAT) that exceeds the tolerance limit of 5 mmHg for each pressure range as described in ANSI Z80.10 – 2003 is provided. In this comparison zero % of the paired differences exceeded the tolerance limit for an IOP range of 7 to 16 mmHg, 2.9 % for an IOP range of >16 to 23 mm Hg, and 5.41% for an IOP greater than 23 mmHg.

In the IOP range > than 23 mmHg, eight of these eyes had a corneal thickness of 595 to 625 microns. The GAT reading in these eyes was on average 7.4 + / - 1.2 mm Hg higher than the FAT1 reading. It is well established in the literature that the GAT will overestimate the IOP when the corneal thickness is greater than 500 microns.5

Correcting the GAT reading using a published nomogram of delta IOP = (-0.0423 x CCT) + 23.38 decreased the number of eyes above the tolerance limit in the > 23 mmHg group of eyes.

See Figure 3 and 4. Regression of FAT1 Readings and Corneal Thickness and Curvature. The FAT1 readings are plotted on the y-axis and corneal thickness and curvature are plotted on the x-axis. The r-squared value for FAT1 versus Corneal Thickness is 0.06. The r-squared value for Corneal Curvature is 0.04.  The low correlation coefficients confirm that the FAT1 readings are independent of corneal thickness and curvature.

See Distribution and Randomness Test, T-Test and Wilcoxon Rank Sum Test. Study Bias Evaluation. The output from the FAT1 device is independent of the user. During the study the data went directly into an electronic secure file. GAT data was manually put into each file.  The testing sequence was randomized. The first ten eyes were tested with the FAT1 first. The next ten eyes with the GAT first. If the FAT1 was first, the FAT1 data went into the file first. If the GAT was first the data was entered into the file first and the FAT1 data electronically went into the file second. Once the data is in the file it cannot be changed. One hundred seven eyes were tested with the FAT1 first and 98 eyes were tested with the GAT first. There was no statistically significant difference between the measurement results and the testing sequence. No user, study or measurement bias was found.

Conclusion:

The accuracy, precision, repeatability and safety of the FAT1 device is confirmed. The FAT1 device measurements are user independent and independent of corneal biomechanics. The FAT1 device measures the variation of IOP with the cardiac cycle and incorporates this data into the displayed IOP. All data is statistically analyzed for precision and accuracy. Data capture is rapid at 0.7 milliseconds. The fixed use disposable prism is an absolute barrier to infectious disease transmission which is a risk with existing tonometer technology.  

 References:

1.    Goldmann H, Schmidt T. Uber Applanationstonometric Ophthalmologic. 1957;134:221-242.

2.    FDA510k141591

3.    Chandler and Grant’s Glaucoma. David Epstein, Rand Allingham, Joel Schuman. Fourth Edition. 1997. Practical Aqueous Humor Dynamics, pp19-20. Tonometry and Tonography, pp 43-44.

4.    Adler’s Physiology of the Eye. Clinical Application. Paul Kaufman, Albert Alm. Tenth Edition. 2003. Circulation, pp 764-767.

5.    Ehlers N, et al. Applanation Tonometry and Central Corneal Thickness. ACTA Ophthalmologica. Vol 53. 1953.

6.    Kohlhaas M, et al. Arch Ophthal. Vol 24. April 2006.             


 Agency for Healthcare Research and Quality. Comparative Effectiveness of Screening for Glaucoma. January 10, 2011.

 

Clinical Comparison of FAT1 to Calibrated Weight Indentation Tonography.

 

Introduction:

 

The Falck Medical, Inc. FAT1 device measures intraocular pressure (IOP), ocular pulsatile amplitude (OPA), the force required for pulsation of the central retinal artery (ophthalmodynamometry-OPH) and aqueous outflow (tonography - TON). The device was cleared for these Indications of Use under FDA510k151491. The primary cause of glaucoma is impaired outflow of aqueous humor 1. All current standard of care pharmacological and surgical treatments of glaucoma are designed to increase aqueous humor outflow. Thus, it is important to be able to measure outflow facility to determine therapeutic efficacy. Measuring IOP is not an accurate assessment of therapeutic response2. Aqueous humor production and IOP vary diurnally3. In glaucomatous and normal eyes, there is no scientific evidence that aqueous humor outflow (Tonography) varies diurnally1,2.

 

The FAT1 device uses the method of tonography to measure conventional outflow facility. During tonography, the force applied, corneal indentation and applanation area are monitored and recorded by the microprocessor and the optical system. Actively recording and monitoring force application, corneal indentation and applanation area is a significant improvement over existing indentation tonographers. The FAT1 device also monitors central corneal contact. The only skill required by the technician or doctor is to initially place the

prism in central contact with the cornea. The measurement process is initiated with central cornea contact. The measurement is automated and independent of the user.

 

Three individual IOP measurements consisting of multiple samples obtained every 7 milliseconds are used to calculate an average IOP measurement. For example, an individual average IOP reading of 16 mmHg consists of approximately 60 samples. Within each individual IOP measurement, the samples are analyzed for repeatability and accuracy (Step 1 analysis). If acceptable an average IOP is calculated. In Step 2 analysis each individual average IOP measurement is analyzed for repeatability and accuracy. The maximum allowable variation for Step 1 and 2 analyses is 10%. Step 1 and Step 2 analysis criteria must be met, otherwise the FAT1 device will prompt for a repeat measurement. The same process is used to evaluate applanation area, force application and corneal indentation. Acceptable measurements are displayed on the CDU with percent variation. Using this process, measurement is user independent.

 

The FAT1 device uses a fixed use disposable prism that is an absolute barrier to the transmission of infectious disease which is an issue with other devices.

 

Methods:

 

The FDA 510k FAT1 Indentation Tonography clinical study was a single site, single investigator, blinded prospective Institutional Review Board approved study. Study oversight and monitoring was provided by an external Contract Review Organization (CRO) and the FDA. Study data analysis was done by the FDA and an independent CRO.  The CRO statistical group was blinded to which participant was in the glaucoma group versus the normal group. Ninety-one subjects and ninety-one eyes were enrolled into the study. The ninety-one subjects (eyes) were coded by a numeric ID and entered into a secure electronic data base. All measurement output went into this secure electronic database. All measurements were performed by two trained ophthalmic technicians.  Two different FAT1 (FAT1A, FAT1B) devices were used in the study for comparison to the Model 30. Before each measurement the FAT1 device performs a calibration routine. All FAT1 devices calibrate to the same internal standards. The Model 30 was calibrated before each use according to the user instruction manual. None of the devices used in the study failed calibration at any time.

 

Two groups of eyes were enrolled for the study. In Group A, sixty-one eyes with a diagnosis of glaucoma (open angle or closed angle) or ocular hypertension were enrolled. The criteria for the diagnosis of glaucoma was glaucomatous nerve fiber layer defects documented by computerized tomography (Heidelberg Retinal Tomograph, HRT2), glaucomatous visual field defects documented by computerized visual field testing (Zeiss Humphrey 30-2 Program) and a history of elevated IOP (>24 mmHg). Additionally, for the diagnosis of closed angle glaucoma, on direct gonioscopy the drainage angle was closed. For the diagnosis of ocular hypertension, the eye enrolled had an IOP greater than 24 mmHg without any glaucomatous findings. Thirty eyes had open angle glaucoma, eight eyes had angle closure glaucoma and twenty-three eyes had ocular hypertension.

 

The average age of Group A subjects was 65.7 +/- 13.0 years and the average age of Group B subjects was 64.3 +/- 8.7 years which was not statistically significantly different, p = 0.60. In Group A there were 38 females and 23 males. In Group B there were 24 females and 6 males.

 

The measurement sequence FAT1 versus Model 30 changed every five eyes. Intra-visit FAT1 variability, inter-visit FAT1 variability and FAT1A and FAT1B intra-visit variability analysis was performed. Operator effect was also analyzed. External independent statistical analysis was provided by Synectechs, Inc., who was blinded as to which was the normal group and which was the glaucoma group. All eyes were used in the analysis. There were no screen failures, no loss to follow-up and no adverse events.

 

The clinical study was conducted in accordance with the abbreviated rules for investigational device exemptions within the meaning of 21 CFR Part 812.2(b), with the rights and protections of investigational subjects in accordance with 21 CFR Part 50-Informed Consent and 21 CFR Part 56-Instituitional Review Board

Regulations. Instituitional Review Board approval was granted on February 16th, 2010. For further protocol details see Section 14.4.

 

Results:

 

In Group A, on computerized visual field testing the average pattern standard

deviation defect was 3.67 +/- 4.1 db, range 1.1 to 20 db and the average mean defect was – 3.0 +/- 3.6 db, range –15.4 to 1.2 db.  The average IOP (Po) was

20.02 +/- 5.5 mmHg with a range of 12.9 to 42 mmHg. The average outflow facility (C) was 0.09 +/- 0.05 ul/minute with a range of 0.01 to 0.22 ul/minute.

 

In Group B the documented IOP was consistently less than or equal to 24 mmHg and none of the thirty eyes enrolled had no examination findings consistent with the diagnosis of glaucoma. Additionally, none of the subjects had any known glaucoma risk factors. Thirty eyes were enrolled in Group B. The average IOP (Po)

was 18.7 +/- 2.4 mmHg with a range of 14.6 to 24 mmHg. The average outflow facility (C) was 0.31 +/- 0.12 ul/minute with a range of 0.16 to 0.6 ul/minute.

 

Two repeat measurements on each of the ninety-one subject eyes were taken with the FAT1 device for a total of 182 outflow facility measurements. Sixty measurements were in the low outflow range of 0.01 to 0.095, sixty-one in the

middle range of 0.10 to 0.17 and sixty-one in the high range of 0.18 to 0.6 ul/minute.   

 

The difference in IOP and outflow facility between Group A and Group B was statistically significant, 20.02 +/- 5.5 vs. 18.7 +/- 2.4 mmHg, p=0.0221 and 0.09 +/ - 0.05 vs. 0.31 +/- 0.12 ul/minute, p < 0.0001.

 

Intra-visit Variability Analysis:

 

Two separate repeat IOP (Po) and outflow facility (C) measurements were obtained with the FAT1 device during the same visit.  There was no statistically significant difference between the first measurement versus the second measurement for IOP and outflow facility, 18.65 +/- 2.46 vs. 18.62 +/- 2.40 mmHg, p = 0.95; 0.31 +/- 0.12 vs. 0.31 +/- 0.12 ul/minute, p=0.99, n=60. 

 

Inter-visit Variability Analysis:

 

At the initial visit and at the follow-up visit within six weeks, the IOP (Po) and

outflow facility (C) was measured with the FAT1 device.  The operator was blinded to the first visit results.  There was no statistically significant difference between the first visit measurement versus the second visit measurement of IOP and outflow facility, 18.66 +/- 2.40 vs. 18.60 +/- 2.46 mmHg, p=0.90;0.31 +/- 0.12 vs. 0.30 +/- 0.12 ul/min, p=0.64, n=60.

 

Testing Sequence Analysis, FAT1 and Model 30:

 

The testing sequence, FAT1 versus the Model 30 changed every five eyes. Distribution and randomness testing of the IOP (Po) and outflow facility(C) measurement difference between the FAT1 and the Model 30 and the testing sequence was carried out using the Wilcoxon test. The mean difference between the FAT1 and the Model 30 and the testing sequence for IOP was 0.0009 mm Hg and for outflow facility was 0.0007 ul/min-mmHg.  The difference between the IOP and outflow facility measurement obtained with the FAT1 device versus the Model 30 and the testing sequence was not statistically significantly different, p = 0.61 and 0.86 for the Wilcoxon two-sided test (n=182).

 

Mean Measurement Difference between the Two Devices:

 

The mean measurement difference between the Model 30-IT and the FAT1 for IOP (Po) was -0.21 mmHg and for outflow facility (C) was -0.006 ul/minute for Group A (n=122), and 0.005 mmHg and -0.001 ul/minute for Group B (n=60). 

 

Ninety-three % and 96% of the Group A paired differences for IOP and outflow facility respectively, are within +/- 1.96 standard deviations of the mean difference. For Group B, 97% and 93% of the paired differences for IOP and outflow facility respectively, are within +/- 1.96 standard deviations of the mean difference. Please see the Bland –Altman data plots (Figures 2a) in Section 14.3.                           

 

Mean Measurement Difference between Group A and Group B:

 

The mean measurement difference for IOP (Po) and outflow facility (C) was compared for Group A versus Group B using the FAT1 and Model 30.  For the FAT1 device, the measurement difference for IOP (Po) and outflow facility (C) was statistically significantly different between Group A and Group B.  Group A IOP was 20.02 +/- 5.5 mmHg and Group B IOP was 18.6 +/- 2.4 mmHg, p =0.0221 (unequal variance). Group A IOP range was 12.9 to 42 mmHg. Group B IOP range was 14.6 to 24 mmHg.  Group A outflow facility was 0.09 +/-0.05 ul/minute and Group B outflow facility was 0.31 +/- 0.12 ul/minute, p < 0.0001.  Group A outflow facility range was 0.01 to 0.22 ul/minute. Group B outflow facility range was 0.16 to 0.6 ul/minute.

 

For the Model 30 device, the measurement difference for IOP (Po) and outflow facility (C) was statistically significantly different between Group A and Group B.  Group A IOP was 19.8 +/- 5.7 mmHg and Group B IOP was 18.7 +/- 1.9, p = 0.047 (unequal variance).  Group A IOP range was 14 to 46 mmHg. Group B IOP range was 15 to 22 mmHg.  Group A outflow facility was 0.08 +/- 0.04 ul/minute and Group B outflow facility was 0.31 +/- 0.12 ul/minute, p < 0.0001.  Group A outflow facility range was 0 to 0.21 ul/minute. Group B outflow facility range was 0.16 to 0.6 ul/minute.

 

Correlation:

 

The correlation between IOP (Po) and outflow facility (C) measurements obtained with the FAT1 versus the Model 30 was studied using linear regression analysis. For Group A the linear correlation coefficient was 0.88 for IOP and 0.77 for outflow facility. The null hypothesis that the slope was zero is rejected, p < 0.0001. For Group B the linear correlation coefficient was 0.69 for IOP and 0.97 for outflow facility. The null hypothesis that the slope is zero is rejected, p< 0.0001. See Figures 1a in Section 14.3.

 

Precision Analysis:

 

1. Operator plus the Device

 

The effect of different operators (operator 1 vs. 2) with the same FAT1 device

 

with the same eye was evaluated for IOP (Po) and outflow facility (C) using

ANOVA. No significant operator effect was found for IOP (p= 1.0) or outflow facility (p= 0.99).

 

2. Same Operator with Different Devices

 

The effect of different devices, FAT1A versus FAT1B, with the same operator and the same eye was examined for the measurement of IOP (Po) and outflow facility (C) using ANOVA. No significant device effect was found for IOP (p=0.96) or outflow facility (p=0.94).

 

3. Replicate Analysis, Same Operator, Same Device

 

The repeat measurement difference for IOP (Po) and outflow facility (C) with the same operator, same FAT1 device and same eye was examined using ANOVA. No significant repeat measurement difference was found for IOP (p=0.95) or outflow facility (p=0.99).

 

Conclusion:    

 

The clinical study results demonstrate the safety, precision, accuracy and repeatability of the FAT1 device. The ability of the FAT1 device to discriminate between glaucomatous and non-glaucomatous eyes is also demonstrated. The clinical study confirms the relationship between the severity of glaucoma and impaired outflow facility.  Eyes with advanced glaucoma had Outflow Values of less than 0.09 ul/mmHg and eyes with moderate glaucoma had outflow values of 0.10 to 0.17 ul/mmHg.

 

References:

 

1.     Becker-Shaffers Diagnosis and Therapy of the Glaucomas. H. Dunbar Hoskins, Michael Kass. Sixth Edition. 1989. Aqueous Humor Dynamics, pp 52-53.

2.     Chandler and Grant’s Glaucoma. David L. Epstein, Rand Allingham, Joel S. Schuman. Fourth Edition. 1997. Aqueous Humor Dynamics, pp19. Tonometry and Tonography , pp 43-44.

3.     Adler’s Physiology of the Eye. Clinical Application. Paul Kaufman, Albert Alm. Tenth Edition. 2003. Aqueous Humor Hydrodynamics, pp 237-289.   


Issues with Current Tonometer Technology, Review of Published Peer Reviewed Literature

The Goldmann Applanation Tonometer is based upon a proven physical principle,  the Imbert-Fick Law. Use of this law to measure intraocular pressure has major drawbacks, which were identified by Professor Goldmann in his original publication: “On Applanation Tonometery by H. Goldmann and T. Schmidt, published in Ophthalmologica 134, 221-242, 1957”.

The original publication was translated from German into English with the assistance of Pamila Seiving, Former Head Librarian, University of Michigan Kellogg Eye Center, and Holger Hansen, M.D., Dr. P.H., Professor of Community Medicine, University of Connecticut School of Medicine. What follows are excerpts taken from the original text, which identify the issues and limitations associated with Applanation Tonometry.

It is important to recognize that non-contact tonometers are not based on the Imbert-Fick Law and therefore are not applanation tonometers. The question to ask is what physical law do they use to estimate eye pressure?  No known proven physical law validating the methodogy of non-contact tonometers can be found in the published literature. They also do not have the ability to compensate for any of the measurement errors that Dr. Goldmann so aptly described. 

1. Corneal Wetness, Thickness and Elasticity

“Imbert-Fick’s Law States that the pressure of a fluid sphere, that is surrounded by a thin membrane can be measured by a counter pressure, which flattens the membrane. His necessary condition is that the membrane is extremely thin and without stiffness and that no other factors are involved”, page 221.

“The 0.5 mm thick cornea represents by no means an extremely thin membrane without stiffness… The surface of the cornea is moistened by fluid. Consequently, capillary forces will operate when the cornea is flattened, depending on the moistening fluid and the adhesive properties of the flattening device and the cornea”, page 222.

“Thus, a number of new problems arise which the abstraction of Imbert-Fick’s law does not take into account”, page 222.

“Elasticity has the (dimension) characteristics of pressure and, therefore acts as additional pressure”, page 223.

“We have assumed thus far that K1 (rigidity factor) is an expression of completely elastic forces. But because the cornea represents a rheological system, it should be presumed that it “floats” under the influence of deforming forces, i.e., after prolonged impact of those forces the cornea gains a new balance … One can see that in this experiment (Table VII and Figure 9), the tonometrically measured pressure declines in spite of manometrically constant pressure… This is an expression of floating of the cornea”, page 232.   

“Under circumstances that vary much from our measurement conditions (abnormally thin or thick cornea, e.g. keratoconus, animal eyes, epithelial edema) errors of several millimeters are to be expected”, page 241.  

As stated by Dr. Goldmann, The Goldmann tonometer cannot measure and therefore cannot compensate for the forces due to corneal wetness, thickness and elasticity. These forces affect the accuracy of all tonometers including non-contact tonometers.

Issue: Current tonometer technology cannot measure the forces due to corneal wetness, thickness and elasticity. Therefore, the current technology cannot compensate for these forces, which limits the accuracy of the measurement.     

Solution: The FMAT1 optical and force generation system measures the forces due to corneal wetness, thickness and elasticity. The device compensates for these forces, eliminating the measurement errors associated with use of the Imbert-Fick Law.    

2. Intraocular Pressure Variation due to the change in Diastolic and Systolic Blood Pressure

“One recognizes the coincidence of the two half rings (Fig 13) but some general technical expertise is necessary because eye pressure varies with the pulsating blood pressure. With correct measuring position, one can see the two half rings moving across from each other, with the inner margins of the half rings moving equally far to the left and the right” , page 240.

“Thus even more since the quickly established eye pressure does not reflect the natural average eye pressure at the time of measurement. The natural average eye pressure at a given point could be recognized only if one could control constant changes due to not only the pulse wave and breathing but also the impact of the outer eye muscles, the changing tension of the lids and emotional influences” , page 241.

Issue: The Goldmann tonometer does not measure the variation in intraocular pressure (IOP) that occurs with the cardiac cycle. IOP is higher in systole than diastole. The pulsating mires of the Goldmann Tonometer are evidence of this. When the inner edges of the mires are aligned, that is the diastolic phase of the cardiac cycle. This can be confirmed by checking the radial pulse when the inner edge of the mires are aligned, which is the end point according to the instruction manual. The mires separate during systole and cannot be aligned. The Goldmann tonometer cannot and does not measure IOP during systole.

The average individual spends one-third of the time in systole and two-thirds in diastole. Because the Goldmann tonometer cannot measure the systolic IOP, the measurement is not a true average IOP.  One third of the IOP data is not being measured.

Other tonometers are not measuring the true average IOP as well. They lack the ability to determine at what point in the cardiac cycle data is being captured. The data capture is random. So a true average IOP is not being measured.

The true average IOP is the combination of the IOP during systole and diastole.

When blood pressure is measured both the systolic (SBP) and diastolic (DBP) is recorded. From those two values, the mean arterial pressure (MAP) is calculated, ((2DBP + SBP) / 3) = MAP.  

Solution: The FMAT1 optical system is able to determine what phase of the cardiac cycle the measurement is captured. The device measures the IOP during systole and diastole for several cardiac cycles and calculates a true average IOP. The Ocular Pulse Amplitude (OPA) is the variation in IOP with the cardiac cycle. The FMAT1 device measures and displays the true average IOP and the OPA.  

3. Repeatability, Precision and Accuracy

Repeatability in a measurement system refers to the ability of an operator to consistently repeat a measurement with minimal variation. Precision is how close the measurements are to each other. The closer repeat measurements are to each other, the less the variation. Accuracy is how close a measured value is to the actual true value.

So the only way you can obtain an accurate measurement is to take multiple repeat measurements, calculate the average or mean value and calculate the variation.  An accurate measurement should have minimal variation.

The Goldmann tonometer only takes one measurement, and it is subjective because the user has to line up the scale. So the measurement is affected by the experience of the user and the subjective alignment of the measurement scale, which causes measurement bias. With only one measurement, it is not possible to determine the accuracy of the measurement.

Other tonometers also have the same issue. Multiple measurements must be taken over time, averaged and the variation examined to determine if the measurement is accurate.

Because decisions are made based upon the measured value, it is critically important that the measurement be repeatable, precise and accurate.

Issue: It is not possible to determine the accuracy of a measurement with current tonometer technology. With only one measurement value, the repeatability, precision and accuracy of the measured value cannot be determined.

Solution: The FMAT1 device samples every millisecond for multiple cardiac cycles. The sample data is analyzed for repeatability, precision and accuracy. The mean and percent variation is displayed to the user for his/her assessment.

4. Transmission of Infectious Disease

Laboratory studies have confirmed infectious prions in the tears of individuals with Creutzfeldt – Jakob Disease (Mad Cow), HBV virus in the tears of Hepatitis – B infected individuals, HCV virus in the tears of Hepatitis – C infected individuals and HTLV virus in the tears of individuals infected with the AIDS virus, (Br J Med Res 2014 Apr 30;4(12):2322-2333, J Infect Dis 2012 Aug 15;206(4):478-485, J Clin Microbiol 1995 Aug 33(8): 2202-2203, Ophthalmology 1986 Dec 93;12:1479-1481). For these potentially lethal diseases, the infectious agent is present in the tears before the infected individual manifests the disease.

At this time, Hepatitis-C is the leading cause of death among all infectious diseases in the US, as reported by Kathleen N. Ly, MPH, CDC Division of Viral Hepatitis, (Clinical Advisor, June 2016, Page 14).

Laboratory studies examining the disinfection efficacy of different regimens for tonometers have found that none are 100 % effective at removal of the  Hepatitis-B Virus, Hepatitis-C Virus and the AIDS Virus. Studies also confirm that the infectious prions of Creutzfeldt-Jacob Disease (Mad Cow) are resistant to all conventional forms of sterilization, (Am J Ophthalmology 2001 Feb;131(2):184-187, Br J Med Res 2014 Apr 30;4(12):2322-2333, Arch Ophthalmol 1994 Nov;112(11):1406-1407, Arch Ophthalmol 1989 Jul;107(7):983-985). 

Studies done in the United States on individuals with Creutzfeld-Jakob Disease (Mad Cow) have confirmed that tonometry is a risk factor for infection: Ocular Tonometry and Sporadic Creutzfeldt-Jakob Disease: A Confirmatory Case-Control Study, Br J Med Res 2014 Apr 30;4(12):2322-2333. The study conclusion was that due to lack of effective disinfection regimens and confirmation that tonometry is a risk factor for infection, disposables are required.

 Issue: Lethal infectious agents of Hepatitis B, Hepatitis C, AIDS and Creutzfeld-Jakob (Mad Cow) Disease are present in tears. Disinfection regimens, even if they are followed, do not eliminate these pathogens.

Additionally, contact tonometers can be used without confirmation of disinfection. They can also be used with or without disposable covers. There is no absolute requirement that they must be disinfected before use, or that a disposable cover is used, or that the disposable cover has been changed after it has been used. There is also no means of preventing reuse of a disposable cover or disposable probe.

Air-puff tonometry once thought to be the solution, is not. It is also a risk factor for transmission of infectious disease. Laboratory studies have demonstrated that the puff of air disperses the tear layer causing micro-aerosol formation. “The ease with which droplets, potentially contaminated with human immunodeficiency virus and other viruses, are dispersed is disturbing. Air-puff tonometry may not be aseptic as previously presumed”, (Microaerosol Formation in Non-Contact Air Puff Tonometry. Britt JM, et al. Arch Ophthalmol 1991 Feb;109(2):225-228)

The micro-aerosols are dispersed in a cloud which are inhaled, deposited on external surfaces and deposited on the external surface of the eye. This creates the potential transmission of infection to not only other patients from contaminated surfaces but directly to staff from inhalation of the infectious micro-aerosols or deposition on the ocular surface.

Solution: The FMAT1 device uses a disposable plastic prism. The prism must be changed before a measurement can be performed on a different patient. The device has a detection system that is able to determine if the prism has been used.  It is an absolute barrier to the transmission of infectious disease.    

The information in this article is the property of Falck Medical, Inc., 07/16/16 Copyright 2016


Scientific Advisory Board Members:

Francis Y. Falck, Jr., MD, PhD, MS, Assistant Clinical Professor, University of Connecticut School of Medicine

James Martone, MD, Assistant Professor, Department of Ophthalmology, Yale University

Elias Reichel, MD, Vice Chairman, Department of Ophthalmology, Tufts University School of Medicine

 


Research Presentations with Falck Medical, Inc Technology:

Clinical Comparison of the Falck Medical Tono-Ophthalmodynamometer (FAT Model 1)
to Calibrated Weight Indentation Tonography. Agency for Healthcare Research and Quality. Department of Health and Human Services. Comparative Effectiveness of Screening for Glaucoma. 01/04/2011.

Clinical Comparison of the Falck Applanation Tonometer (FAT Model 2) to Goldmann Applanation Tonometer. Agency for Healthcare Research and Quality. Department of Health and Human Services. Comparative Effectiveness of Treatment of Glaucoma. 01/04/2011.

Macular Society Meeting, 02/2010. Anti-VEGF Injections Decrease Ocular Perfusion Pressure.

Association in Research in Vision and Ophthalmology Meeting, 05/2010. Anti-VEGF Injections and Ocular Perfusion Pressure.

World Forum 2010, Cambridge University, 08/2010. Strategies for Preventing Blindness.

World Glaucoma Congress, Paris, France , 07/2011. Anti-VEGF Injections Independently Increase Intraocular Pressure and Decrease Ocular Perfusion Pressure.

Association for Research in Vision and Ophthalmology, 05/2000. Falck Medical Applanation Tonometer Intraocular Pressure Measurements, Corneal Thickness and Corneal Curvature.

 


Dr. Francis Falck, Chief Executive Officer, Falck Medical, Inc received the “2010 Man of the Year in Medicine and Healthcare Award” at the World Forum 2010, Cambridge University, Cambridge, England on August 18th, 2010.

Dr. Falck was recognized for his milestone work developing diagnostic technology that will be used worldwide to prevent blindness and stroke.

The World Forum 2010 was attended by 150 scholars from 40 different countries.


Instructions for Disinfecting External Surfaces of Falck Medical, Inc FMAT1 Multifunction Device Using Clorox Disinfecting Wipes

1. Only Clorox Disinfecting Wipes are to be used. See attached Product Label.

2. Do not touch the emitter or detector in the prism head with the Clorox Disinfecting Wipe.

3. To protect the emitter and detector, perform surface disinfection after all patient testing is completed with the used prism in place.

4. Turn the power off to the FMAT1 Device.

5. Remove a single Clorox Disinfecting Wipe from the container. Squeeze excess fluid from the wipe.

6. Wipe the external surfaces with a single wipe.

7. Let all surfaces air dry.

8. Turn power back on to the FMAT1 Device.

9. After the FMAT1 Device completes the check routine, replace the prism with an unused FMAT1 Prism.

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