Diaton Tonometer Clinical Trials + Principle of Operation - reply

Discussion in 'Optometry Archives' started by DevelopAll, Oct 30, 2008.

  1. DevelopAll

    DevelopAll Guest

    Dear Bill,

    There is a lot of information on the actual Diaton website:

    It Includes Clinical comparison trials with GAT, Tonopen as well as
    other publications.

    Publication/Trials Extracts:

    # 1. Comparison of the Diaton Transpalpebral Tonometer Versus 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

    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.

    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.

    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.

    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.

    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

    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
    · To compare intraocular pressure (IOP) measurements obtained with
    Diaton trans-palpebral tonometry versus Tonopen applanation tonometry
    in children and adults.


    · 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.


    · 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

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


    · 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.


    · 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

    · 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
    · 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

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

    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

    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

    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

    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

    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,
    DevelopAll, Oct 30, 2008
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