Diaton Tonometer Clinical Trials + Principle of Operation - reply

Dear Bill,

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/inde...meter_Goldmann_Tonopen_Applanation_Tonometers

Publication/Trials Extracts:


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

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_Tonometer_Tono_Pen_Applanation

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/inde...parison_Diaton_Non_Contact_Tonometer_Glaucoma

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/inde...on_Tonometry_Kerato_Photorefractive_Surgeries

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.

Results: In the patients who had not been subjected to photorefractive
surgery the mean applanation IOP was 16.1±2.6 mmHg, the mean IOP
evaluated with Diaton 14.7±2.5 mmHg. At that correlation between
values of the applanation tonometer and Diaton was highly reliable
r=0.73. The mean of the real IOP after applanation value conversion
was 15.4±2.4 mmHg. Pearson correlation coefficient between real IOP
and the Diaton result was 0.89. In the groups of patients, who
underwent photorefractive vision correction, the mean applanation IOP
12.4±2.91 mmHg, modified taking into account keratometry IOP rates
13.9±3.0 mmHg, mean diaton-tonometry result 15.1±2.75 mm Hg - increase
of correlation coefficient from 0.51 to 0.81.

Conclusions: The cornea thickness is an important factor in IOP
evaluation and monitoring, and necessitates the inclusion of corneal
pachymetry in the program of examination the patients with suspicion
of glaucoma and hypertension, especially after various
keratorefractive surgeries while using the traditional corneal methods
of ophthalmotonometry. At the same time clinical application of
transpalpebral scleral diaton tonometer makes it possible to evaluate
IOP using only one device, the procedure being efficient, economical,
simple and requires no additional instrument examination.

XXV Congress of the ESCRS, Stockholm 2007


Also - the description link has in depth overview on the principles of
the ballistic tonometry:

1.4 Advantages of ballistic transpalpebral tonometry with Diaton
Tonometer.

1.4.1 During the corneal tonometry it is very difficult to prevent the
increasing of orbicular and palpebral muscles tone at the moment of
measuring in reactive patients, that leads to IOP increasing. The
ophthalmotone increasing may be also connected with the blood pressure
increasing during the tonometer's bringing near the open eye. Diaton
tonometer is out of the patient's field of vision.

1.4.2 It is known that a tear may contain pathogenic bacteria and
viruses such as hepatitis B virus, herpes, adenoviruses, AIDS. But the
problem of tonometers sterilization is far from perfection. During
tonometry with Diaton device the direct contact with the eyeball is
excluded.

1.4.3 The corneal tonometry is contraindicative in conjunctivitis,
erosions, sores, hypostasis and cornea dimness. Using Diaton Tonometer
the IOP measuring in most of such cases is possible.

1.4.4 The corneal tonometry is impossible without prior anesthesia,
which often causes conjunctiva irritation, short-term IOP increasing,
hypostasis and loosening of cornea epithelium and sometimes allergic
reaction. These undesirable reactions are excluded while measuring
with Diaton tonometer.


For any additional questions - you can contact the company directly
either by form on the site: email or
phone: 1-877-diatons (877-342-8667)

I hope you will find the follow up helpful and useful.

Best regards,
DA