Clin Exp Ophthalmol. Dec;34(9) Dynamic contour tonometry: principle and use. Punjabi OS(1), Kniestedt C, Stamper RL, Lin SC. The PASCAL Dynamic Contour Tonometer (DCT) from Ziemer is a slitlamp mounted tonometer for measuring intraocular pressure IOP independent of corneal. The gold standard for assessing IOP is Goldmann applanation tonometry (GAT). Recently, the dynamic contour tonometer (DCT) has become.

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Dynamic Contour Tonometry Overcoming the limitations dynamlc applanation tonometry. Purchase access Subscribe to JN Learning for one year. Several studies 4 – 7 have reported that most patients with ocular hypertension have a high CCT, which may lead to a spuriously high IOP measured using an applanation device rather than truly elevated IOP.

PASCAL® Dynamic Contour Tonometer from Ziemer Group

Tonkmetry intra- and interobserver variability found with GAT is very similar to the results found in other studies. At present, it is unclear why the difference in this study population is so large.

Most nonpathologic corneas will be well within the scope of what DCT can handle correctly, however. You can manage this and all other alerts in My Account. Register for email alerts with links to free full-text articles Access PDFs of free articles Manage your interests Save searches and receive search alerts.

Relationship between corneal thickness and measured intraocular pressure in a general ophthalmology clinic. Furthermore, corneal shape radius and astigmatismelasticity, and rigidity differ widely among patients.

PASCAL® Dynamic Contour Tonometer from Ziemer Group – Product Description and Details

The effect of corneal thickness on applanation tonometry. According to the manufacturer 18 and cntour studies 1920 on cadaver eyes, DCT measurements are minimally dependent on structural properties of the cornea, particularly CCT. This reduced the amount of inter- and intraobserver variability for both tonometers but did not change the finding that the intra- and interobserver variability found for DCT 0.

The use of DCT wasquick and easy. A piezoelectric sensor integrated into the contoured surface of the tip measures IOP without systematic errors caused by these forces or by changes in the corneal biomechanical properties. The ultrasonic CCT was measured after 15, 30,and 45 minutes of immersion. Submitted for publication January 8, ; revised May 14, ; accepted June 9, The results with Goldmann applanation tonometry were consistently below true IOP by an average of -4 mm Hg.


Dynamic contour tonometer DCT tip. Before each reading, the measuring drum was reset to approximately 2 mm Hg, and the mean of three consecutive readings was recorded. Interobserver variability was 0. Hemidiscs overlap approximatelyone fifth of the disc diameter 2 times the ring width.

The mean IOP reading for each measurement method was recorded. Bull Soc Ophtalmol Fr. Over the past four decades, Goldmann applanation tonometry GAT has become the standard for routine measurement of IOP, as the method has proven to be robust and easy to use with low intra- and interobserver variability.

One hundred fifty healthy volunteers from the hospital staff with normal eyes on slit lamp examination and no history of previous ocular diseases, trauma, or surgery contributed eyes that dynzmic evaluated in a prospective single-center study.

The device seems to be particularly useful for IOP measurements in post-LASIK eyes as well as in other corneas that are thinner or thicker than average and in which the practitioner cannot achieve fynamic readings by force tonometry.

For this reason, it is controversial whether CCT is an independent risk factor for progression of established glaucoma.

Dynamic contour tonometry: principle and use.

DCT seems to be an appropriate method of tonometry for routine clinical use. An important factor for the accuracy of IOP measurements is the variability that occurs between measurements performed by the same observer intraobserver or by different observers interobserverwhen measuring IOP in the same eye.

Twenty freshly enucleated human cadaver globes that were unsuitablefor transplantation were provided by the eye banks of San Diego, Calif, andPortland, Ore.

Likewise, whether there is an effect of topical drugs on biomechanical properties of the cornea other than CCT needs further validation, as there is evidence that some IOP-lowering drugs may alter tissue 3637 by stimulating the degradation of extracellular maxtrix eg, modulation of matrix metalloproteinases in conjunctival and subconjunctival tissue.

This indicates parallelism between the 2 methods.

To test for significant differences between the ICCs, we calculated tonometgy sum of variance of all noise components for the two tests all variance components except the subjects variance component. Submitted for publication August 11, ; final revision received March31, ; accepted April 6, Mixed-effects models incorporated fixed and random effects.

Therefore, patients with normal-tension glaucoma may have a higher IOP than measured. Register for email alerts with links to free full-text articles Access PDFs of free articles Manage your interests Save searches and receive search alerts.


Purchase this article with an account. Corneal preparation of eye bank eyes for experimental surgery. Create tonojetry free personal account to access your subscriptions, sign up for alerts, and more.

To evaluate intra- and interobserver variability, IOP was measured in eight eyes by four observers. To determine whether elevated IOPs alter the corneal curvature and theaccuracy of DCT, 3 eyes were subjected to optical keratometry and cornealtopography Orbscan II dgnamic a maximal IOP of approximately 58 mm Hg after thelast trial series. Even when the eye-banked corneas were thinned post-mortem by photorefractive keratotomy or dehydration, DCT yielded readings very close to true IOP, whereas results with Goldmann applanation tonometry and pneumatonometry deteriorated further.

Applanation tonometry and central corneal thickness. The bottleheight was adjusted at 5 cm to begin each trial. Dynamic contour tonometry and GAT intraocular pressure differences significantly increased with older age slope, 0. Nevertheless, it remains to be elucidated whether various cotnour glaucoma medications might confound the relationship between Toonometry and IOP.

To reduce the risk of observer bias, the more subjective GAT measurements have always been dnamic before the DCT readings, which cannot be influenced by the examiner. In contrast to GAT, for which the index on the scale is set at 2-mm increments to take into account the intra- and interobserver variability, DCT gives pressure readings with a dtnamic of one decimal place.

Kala Pharmaceuticals announced that it will be presenting at the Spotlight on dry eye session at the Ophthalmology Innovation Summit at the American Society of Cataract and Re…. Similar findings have been reported by other researchers who have also noted that this effect persists even 3 months postoperatively. Bayesian adaptive assessment of the reading function for vision: Reduction in intraocular pressure after excimer laser photorefractive keratectomy: Tonkmetry right eye was always measured first.

Dynamic contour tonometry compared with Goldmann applanation tonometry, pneumotonometry and intraocular manometry in cadaver eyes.

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