No Contact with Cornea, No Anesthesia Drops, No Risk of Infecting -
more at http://www.TonometerDiaton.com

Diaton tonometer video is available on the site and through google
video: http://video.google.com/videoplay?docid=8268011334455802753

It certainly would have made the post credible if a bit was said about
the principles of operation.

Bill

For example, I was intrigued by how it was possible to have a dashboard
display of tire pressure problems. I was both surprised by the
simplicity and the fact that pressure was measured very indirectly. The
ABS system compared the rolling rates among the various wheels rather
than actually measuring pressure.

Getting back to IOP, It should not be difficult to give a one or two
sentence summary of how the device works and how it gets around the
eyelid being in the way. A comparison of the accurcies of various
methods would not hurt. So far, I have not seen that either in the posts
or on the web site I visited.

Bill

Studies suggest that it is adequate for checking change but not so
good at absolute values.

http://web.njit.edu/~alvarez/CV%20Papers/Proview%20Alvarez%20et%20al.pdf

Auteur(s) / Author(s)
GARCIA RESUA Carlos (1) ; GIRALDEZ FERNANDEZ Maria J. (1) ; CERVINO
EXPOSITO Alejandro (2) ; GONZALEZ PEREZ Javier (1) ; YEBRA-PIMENTEL Eva
(1) ;
Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)
(1) Department of Applied Physics (Optometry Group), University of
Santiago de Compostela, Santiago de Compostela, ESPAGNE
(2) Neuroscience Research Institute, School ofLife and Health Sciences,
Aston University, Birmingham, ROYAUME-UNI
Résumé / Abstract
Purpose. The TGDc-01 PRA (Ryazan State Instrument, Ryazan, Russia)
tonometer is a new portable small-sized tonometer that measures
intraocular pressure (IOP) through the eyelid. The purpose of this study
is to assess the repeatability of the TGDc-01 IOP measurements by
comparing them against those obtained with Goldmann tonometer and with
those from Perkins applanation tonometer, Xpert (Reichert, Depew, NY)
noncontact tonometer, and Tono-Pen XL (Medtronic Solan, Jacksonville, FL)
digital tonometer. Methods. Fifty-eight right eyes of 58 young subjects
were measured with each of the tonometers. Noncontact tonometry was
performed first, followed by Goldmann and Perkins applanation tonometer
(in random order), digital Tono-Pen XL, and finally TGDc-01 tonometer
(sitting and supine position). Correlation analysis was used to evaluate
the relationship between the Goldmann tonometer and the remaining
tonometers used in this study. Plotting the difference between the
methods against mean was also done to compare the tonometers. The
hypothesis of zero bias was examined by a paired t-test. The 95% limits
of agreement (LoA) were also calculated. Results. TGDc-01 showed no
statistical difference between the IOP measurements obtained in sitting
and supine positions. A poor relationship between the TGDc-01 and
Goldmann tonometer was found (r2 = 0.173; p = 0.001). Although the mean
differences between Goldmann and Tonopen XL, Xpert, and TGDc-01 IOP
measurements were statistically significant, the wider 95% LoA was
observed when comparing the Goldmann and TGDc-01 tonometers. Computation
of the 95% LoA resulted in a wide bias range when comparing the TGDc-01
with all the tonometers used in this study. Conclusions. The TGDc-01 PRA
tonometer was not comparable with the other techniques used in the study.
The wide dispersion range of the values obtained shows low repeatability
of the TGDc-01 for screening purposes. These results could be because of
the technique of measurement and/or interindividual variables.
Revue / Journal Title
Optometry and vision science   ISSN 1040-5488   CODEN OVSCET
Source / Source
2005, vol. 82, no2, pp. 143-150 [8 page(s) (article)] (44 ref.)

Bill

In the one I linked to in the previous post, Proview was repeatable
with itself, with about a 3mmHg variation measure to measure; that is
not far off other methods.  It did not compare very well to Goldmann
tonometry.  I think its value is in patient self monitoring not in
intial diagnosis or as an office instrument.

Judy

There is a lot of information on the actual Diaton website:
http://www.TonometerDiaton.com

It Includes Clinical comparison trials with GAT, Tonopen as well as
other publications.
http://www.tonometerdiaton.com/index.php?do=home.Comparison_clinical_...

Publication/Trials Extracts:

# 1. Comparison of the Diaton Transpalpebral Tonometer Versus Goldmann
Applanation
http://www.tonometerdiaton.com/index.php?do=home.Comparison_Study_Dia...

R. S. Davidson 1; N. Faberowski2 ; R. J. Noecker3 ; M. Y. Kahook1
1. Ophthalmology, Rocky Mountain Lions Eye Institute, Aurora, CO, USA.
2. Ophthalmology, Denver Health Medical Center, Denver, CO, USA.
3. Ophthalmology, UPMC, Pittsburgh, PA, USA.

Financial Disclosure
The authors have no financial interest in the subject matter being
presented

Background
Diaton tonometry is a unique approach to measuring intraocular
pressure (IOP) through the Eyelid. It is a non-contact (no contact
with cornea), pen like, hand-held, portable tonometer. It requires no
anesthesia or sterilization.

Purpose
To investigate the agreement in the measurement of intraocular
pressure (IOP) obtained by transpalpebral tonometry using the Diaton
tonometer versus Goldmann applanation in adult patients presenting for
routine eye exams.

Methods
Retrospective chart review of consecutive IOP measurements performed
on 64 eyes of 32 patients age 34-91 years with both the Diaton
tonometer and Goldmann applanation. Results between groups were
examined using analysis of variance (ANOVA) where appropriate.

Results
Mean IOP was 15.09 +/-4.31 mm Hg in the Goldmann group and 15.70
+/-4.33 mm Hg in the Diaton group (p=0.43).
Mean IOP variation between groups was 1.74 +/-1.42 mm Hg (range 0-8).
83% of all measurements were within 2 mm Hg of each other.

Conclusions
The transpalpebral method of measuring IOP with the Diaton tonometer
correlates well with Goldmann applanation. Diaton applanation may be a
clinically useful device for measuring IOP in routine eye exams.

# 2. Comparison of the Diaton Transpalpebral Tonometer Versus Tono-Pen
Applanation
http://www.tonometerdiaton.com/index.php?do=home.Comparison_Diaton_To...

Theodore H. Curtis, M.D.1, Douglas L Mackenzie, M.D.1, Robert J.
Noecker M.D.2, and Malik Y. Kahook M.D.1
1The Rocky Mountain Lions Eye Institute, University of Colorado Health
Sciences Center, Aurora, CO
2Eye and Ear Institute, University of Pittsburgh Medical Center,
Pittsburgh, PA

Financial Disclosures
· None of the authors have financial interests relevant to the supject
discussed.
Purpose
· To compare intraocular pressure (IOP) measurements obtained with
Diaton trans-palpebral tonometry versus Tonopen applanation tonometry
in children and adults.

Introduction

· Goldmann applanation is the gold standard for IOP measurement
· It has been supplanted by TonoPen applanation in many settings
because of it's ease of use, portability, convenience, and minimal
training requirements.
· The TonoPen requires contact with the corneal surface, and has the
risks of iatrogenic corneal injury, spread of pathogens, and requires
topical anesthetics.

Introduction

· The newly-developed Diaton tonometer is a handheld device that
measures pressure through the tarsal plate (Figures 1 & 2).
· It avoids contact with the cornea and the need for topical
anesthesia.

Figure 1: The Diaton Transpalpebral Tonometer
Figure 2: Using the Diaton Tonometer

Methods

· We looked at 74 eyes of 38 consecutive patients who received both
Tonopen and Diaton tonometry
· TonoPen measurements were taken in the sitting position following
topical anesthesia with proparicaine.
· Diaton measurements were performed in the sitting position with the
patient gazing at a 45o angle, placing the eyelid margin at the
superior limbus. If necessary, gentle traction was placed on the brow
to align the lid with the limbus. The device was activated when the
signaling mechanism indicated the device was vertical.

Results

· Age range 3-91 years of age (mean 47.5 years).
· The average IOP with the Diaton was 16.24 (+/-5.11 mm Hg; range =
7-32 mmHg).
· The average IOP with the TonoPen was 16.37 (+/-4.90 mm Hg; range =
8-33 mmHg).
· The mean variation between the two modalities was 1.59 mmHg (+/-1.31
mm Hg; range = 0-6 mmHg).
· Eighty-one percent of all measurements were within 2 mmHg of each
other (Table 1).
· There was no statistically significant difference in mean IOP values
obtained with the two devices (p=0.87). Table
Conclusions

· The Diaton tonometer pressure measurements correlated well with
TonoPen measurements in this retrospective review.
· We did not find problems performing the exam in children, and many
were reassured by the fact that no drops were needed.
· There may be a notable benefit in patients after refractive surgery
or with corneal pathology since the Diaton does not applanate the
cornea.
· The Diaton tonometer appears to be a clinically useful device in the
IOP measurement of both children and adults.

# 3. Clinical comparison of the Diaton and the Non-contact Tonometers
with the Goldmann applanation tonometer in glaucoma patients
http://www.tonometerdiaton.com/index.php?do=home.Clinical_comparison_...

Nesterov A.P. M.D., Illarionova A.R. M.D., Obruch B.V. M.D.
Eye Diseases Department, Russian State Medical University, Moscow,
Russia

Purpose: Study of intraocular pressure evaluation (IOP) reliability
using non-invasive devices, which require no anesthesia:
transpalpebral scleral Diaton tonometer and non-contact
pneumotonometer (NCT).

Method: Here the prospective comparative case series clinical study is
presented. 87 patients (146 eyes) suffered from glaucoma (m:f = 51:36;
age distribution: 29-85 years) were examined. For comparison IOP
values received with Goldmann applanation tonometer (GAT) using the
traditional methodology and digital mean values received with Diaton
and NTC were used.

Results: Mean IOP was 17,4±7,6 mmHg with GAT, 16,7±5,58 mmHg with
Diaton, 21,4±9,13 mmHg with NCT. Minimum IOP value was 6,0 mmHg with
GAT, 6,0 mmHg with Diaton, 5,0 mmHg with NCT; maximum value was 40,0
mm Hg with GAT, 36,0 mmHg with Diaton, 47,0 mmHg with NCT. There was
no significant difference of IOP values (t = -0,51, p < 0,001). The
Pearson's correlation coefficient was r=0.89, p < 0,001 between GAT
and Diaton; r=0,87, p < 0,001 between GAT and NCT. There was observed
high correlation of both tonometers with GAT in IOP range up to 30 mm
Hg. In case of IOP significant increase NCT showed IOP overestimation
up to 7 mm Hg; Diaton showed IOP underestimation up to 4 mm Hg.

Conclusions: The study shows high reliability of transpalpebral
screral Diaton tonometer enough for clinical purpose. It has both
accuracy correlating with GAT and NCT's safety and operating speed.
Diaton advantage is the possibility to evaluate IOP in cornea
pathology, which is very important in glaucoma patients after corneal
including laser surgeries.

ESCRS Meeting, London, September 2006

# 4. Clinical use of transpalpebral diaton tonometry after
keratophotorefractive surgeries
http://www.tonometerdiaton.com/index.php?do=home.Clinical_Trans_Palpe...

T. Dzhafarli MD., A. Illarionova MD.

Purpose: The purpose of the study is to evaluate the clinical use of
transpalpebral scleral tonometry, reliability of its application in
patients with refraction anomaly in pre- and postoperational periods,
dynamics of eye morphometric rates (pachymetry of the central corneal
zone, IOP) and their correlative bond before and after photorefractive
surgery.

Setting: Russian State Medical University, Moscow, Russia.

Methods: The following factors were exclusion criteria from the study:
cornea, upper eyelid and clera pathology. We have analyzed the results
of prospective comparative case series clinical study in 98 patients
(194 eyes) with ametropia, from which 39 persons (76 eyes), who had
been subjected to excimerlaser vision correction. All patients were
subject to the comlete refractive examination, including
keratotopography, wavefront-aberrometry, US-biomicroscopy,pachymetry
corneal thickness in central zone, IOP was measured with Goldman
applanation tonometer, pneumotonometer and transpalpebral scleral
Diaton tonometer using traditional methodology.