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Recent paper by U.Toronto Eye researcher showed that many Hospital GOLDMANN tonos were not calibrated for years and certainly not sterilized between patients as per Ont. Gov. Regs. DISPOSABLE tips available but rarely used in Toronto.
Tonopen with Latex mini-condom avoids X-infection + scleral tonometry avoids any damage to cornea. Divide scleral readings by 2. Original tonometry was scleral by Dr.DONDERS. Have not missed Glaucoma in 50,000 pts.over 25y.
After 50y., movement away from Goldmann to newer Tonometers. iCARE an example. Also through-the-lid DIATON tonometer USA approved @ $2,500. PROVIEW though-the-lid @ $100 useful for follow-up. China buying lots. Inventor Dr.B.FRESCO MSc OD FAAO in Toronto.
Single IOP as valuable as non-fasting Blood sugar. Suggest Tonometry OK for follow-up but nowadays non-mydriatic fundus camera + Fast Vis. Field + OCT + HR3 gives precise diagnosis + hard copy.. Note Bascom Palmer charges $1,500 PER EYE for technical assessment.
The new developments in tonometry technology are wonderful, but tonopen is still an instrument intended for use on the central cornea. Any peer reviewed literature supporting your protocol for scleral tonopen (ie. reading divided by 2)?
As for concerns over sterilization of goldmann tonometer tips, thats an easy one to deal with in your own practice...just sterilize it between patients.
As previously posted new patent awarded to LA OMD WALLACE for TONOPEN modified for scleral reading. Should be on sale in a few years. Compare scleral/corneal figues for yourself.
Repeat through-the-lid DIATON approved by USA govt.; on sale in Can. & USA.
Pardon, my skeptism, but it just seems highly speculative given that we don't even really know how much to adjust IOP measurements based on Pachymetry of the central cornea.
New tonometers DIATON & PROVIEW are NOW on sale.(see Google)
Maths. of through-the-lid scleral tonometry using DIATON on its web site.
Agree about thickness cornea; thats why IOP not State of Art basis of DIAGNOSIS. OK for simple screening if more advanced instruments are too expensive for a community OD/MD. Better than nothing. OK for follow-up if same machine used @ same time of day.
Situation similar to cardiology before invention echocardiogram/ Doppler/ CAT/MRI with mercury BP + stethoscope,
Ant & post.OCT/HRT3/fundus camera gives precision instead of subjective impression and multiple variable factors affecting IOP. Technical revolution.
There were papers on Scleral tonometry in the 1950s; but like battery engines vs gasoline, the GOLDMANN took the lead. Also like battery engines, scleral tonometry is now returning (DIATON) because patients like it and its safe (no xinf./no corneal damage/no allergic reaction). Patients are usually not read the ALCAINE warnings.
Comparison of the Diaton Transpalpebral Tonometer Versus Goldmann Applanation
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.
The authors have no financial interest in the subject matter being presented
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.
For full details please visit:
Comparison of the Diaton Transpalpebral Tonometer Versus 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
None of the authors have financial interests relevant to the subject discussed.
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 anesthesia.
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 45? 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 cornea.
The Diaton tonometer appears to be a clinically useful device in the IOP measurement of both children and adults.
Li J, Herndon LW, Asrani SG, Stinnett S, Allingham RR. Clinical comparison of the Proview eye pressure monitor with the goldmann applanation tonometer and the TonoPen. Arch Opthalmol 2004;122:1117-21.
Eisenberg DL, Sherman BG, McKeown CA, Schuman JS. Tonometry in adults and children: a manometric evaluation of pneumotonometry, applanation, and TonoPen in vitro and in vivo. Ophthalmology 1998;105:1173-81.
Diaton: digital portable tonometer of intraocular pressure through the eyelid. Operation Manual. Ryazan State Instrument Making Enterprise. Ryazan, Russia.
Garcia Resua C, Giraldez Fernandez MJ, Cervino Exposito A, Gonzalez Perez J, Yebra-Pimentel E. Clinical evaluation of the new TGDc-01 "PRA" palpebral tonometer: comparison with contact and non-contact tonometry. Optom Vis Sci 2005;82:143-50.
Troost A, Yun SH, Specht K, Krummenauer F, Schwenn. Transpalpebral tonometry: reliability and comparison with Goldmann applanation tonometry and palpation in healthy volunteers. Br J Ophthalmol 2005;89:280-3.
Losch A, Scheuerle A, Rupp V, Auffarth G, Becker M. Transpalpebral measurement of intraocular pressure using the TGDc-01 tonometer versus standard Goldmann applanation tonometry. Graefes Arch Clin Exp Opthhalmol. 2005;243:313-6.
For full details please visit:
As to MDs refracting, here in B.C. a GP asked the College of Physicians and Surgeons if he could refract some years back. They said he could, if he received proper training and endorsement from an ophthalmologist, which he did. In terms of eye examinations, in simplistic terms, GPs function bascically the same with eyes as they do with other organs: they do not need to recognize 300,000 eye diseases and disorders, they only need to differentiate a healthy eye from an unhealthy eye, then make the referral if indicated.
Same with us contact lens tech, optician types. We just have to recognise the un-healthy from the healthy and refer. I don't have to know what type ulcer, what treatment is indicated, etc. Just be able to tell this needs some one smarter than I working on it.
MD's in Ontario are allowed to perform any medical function without training beyond their MD license. This includes any surgery or any other controlled act other than scaling teeth. Without further training, they are allowed to do cosmetic/plastic surgery, eye exams or dispense glasses. In practical terms however the CPSO would not be happy if a GP did kidney transplants. On the other hand, look at the recent controversy with people dying following liposuction from family physicians doing the procedure. In Franklin's case he was only refracting eyes. He neglected to perform a glaucoma test, or any other function beyond autorefraction. I once saw a young girl with a macular hole, corrected acuity of 20/100 in the eye, with a clear health acocunt from a refracting MD. That's why autorefraction is only part of a complete eye examination.
What treatment is indicated for a macular hole? Beyond a lot of follow-up, pictures and insurance billing?
Typically a vitrectomy is performed, then they inject a gas bubble and have the patient lay face down as much as possible for a few weeks.
Thanks Ory. Don't personally know too much about treatments for the back of the eye, despite having sat through hours of presentations and having a daughter that has had a vitrectomy.
Eye exams included Ophthamoscopy with PANOPTIC + confirmation with expensive UK Rayner Trial lenses; (not only auto-refraction with HUMPHREY-ZEISS). SCLERAL Tonometry peformed as thought necessary. No missed case of glaucoma found by CPSO in 25 years.
Optometrist from Lindsay was hostile witness. Only after trial found out that he had sent secret complaints to CPSO. Patient of his came to me for a second opinion. No significant difference. She then demanded $60 returned; when I declined, she complained to CPSO.
Through-the-Lid DIATON scleral tonometry now received Canadian federal approval and is sold here to GPs at Primary Practice meetings.
Ontario Opticians will soon have the right to refract as in BC & Manitoba. Refraction being taught to opticians @ Georgian & Seneca colleges.
BC has a $10,000 private 6-months course for Optician licence.
GPs will refract as well as opticians and probably Nurse Practitioners.
BTW Canada, UK & USA selling prescription single vision specs. for $30 on the web.
BC has a $10,000 private 6-months course for Optician licence.
This is hardly breaking-news. The BC private Opticianry course has been in operation for twenty-four (24) years. Why this post?
"Dr. Franklin acknowledged in his evidence that he performed scleral tonometry on
patients at the relevant time. Dr. Franklin testified that he believes that scleral
pressure is approximately double corneal pressure. He made reference to the fact that
he had been told this by somebody 25 years ago. When he was specifically asked
about research studies in this regard, he replied that some people in India had
measured pressures on cadavers, but he presented no evidence in support of this."
"Dr. Franklin’s C.V. has been exaggerated. It indicates that he is a member of the
Glaucoma Research Society. However, he testified that there was only an invitation to an annual speaker’s dinner with no other involvement. He is also listed as a member of the Jung Foundation but in effect is only a donor. Dr. Franklin testified that the Glaucoma Society and Jung references should be removed from his C.V."
"Dr. Franklin was found by the Committee to lack insight and he did not always accept opinions that did not accord with his views"
"Nevertheless, the Committee is troubled by the fact that Dr. Franklin continues to express the view that scleral tonometry is acceptable notwithstanding the extensive evidence that it is not."
And why in the world do you remain so fixated on this scleral tonopen technique of yours? There is absolutely no published research towards it's validity/repeatability. If you're reasonably skilled with a Goldman there should be absolutely no risk of harm in applanation.
Actually I think scleral tonometry came about for O.D.'s back when they were not allowed to use anesthesia. Don't think I have ever heard of an O.D. using any other form of tonometry. I the last two decades OMD's seem to trust air puff stuff for preliminary exams. Don't see why you jumped on this poor GP.
Every one has known that corneal tonography was more reliable but don't think it is used much today unless a problem is at least suspected.
Why just think a half second of valuable "chair time" (now much more important than a mere patient) is required for the air puff. Several actual minites required for a Goldman.
What I'm wondering is how this GP could think scleral tonometry with a tonopen is even remotely acceptable when there is no published research to support it's use in that situation. Now consider this; the MD's scleral technique involved performing tonopen on the sclera and then dividing the reading by 2. Where in the world did that ever come from? How is it even reasonable when the nonogram for adjusting IOP based on corneal thickness is bunk? I wonder, did he even get a 5% confidence using tonopen on the sclera?
As I recall, tonometry is a screening tool. If you really want to evaluate the inflow/outflow you will perform tonography. Do you hold the position that scleral applination will work in this case.
Tonography can however have various uses in research.
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