DYNAMIC CONTOUR TONOMETRY PDF

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

Claude Kaufmann ; Lucas M. After application of topical anesthesia to the cornea, a paper stripe impregnated with fluorescein was used to stain the precorneal tear film cotnour before IOP measurement. Other studies 68 – 10 found that patients with normal-tension glaucoma have thinner corneas than those of the general population. Create a free personal account to download free article PDFs, sign up for alerts, customize your interests, and more.

Dynamic Contour Tonometry

Further studies are warranted todetermine its reliability in patients and the effect of corneal thickness. In contrast to GAT, multivariable regression analysis showed no significant effect of tonoometry thickness, corneal curvature, astigmatism, anterior chamber depth, and axial length on DCT readings. Sign in to access your subscriptions Sign in to your personal account. Purchase access Subscribe now.

The transducer and the anterior chamber were kept at the sameheight. Glaucoma Today delivers important information on recent research, surgical techniques, clinical strategies, and technology. The tube was connectedto a manometric transducer, an isotonic sodium chloride solution infusionbottle, and an open-air reference tube. Further studies are indicated to further elucidate theproperties, usefulness, and accuracy of DCT in clinical situations. Since a value is given automatically by the strain gauge andthe automatic software in the base station, there is less chance for observerbias with this system than with GAT.

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However, in the range of 18 to 23 mm Hg, an underestimationof 3 or 4 mm Hg could be clinically problematic, and the increasing underestimationof IOP by PTG in the high-pressure range mm Hg might also be clinicallysignificant. The stopcock at the gauge needle tube was closed atthe maximal IOP and the globe was left in the cadaver eye holder but unhookedfrom the reservoir bottle distal to the stopcock. Sign in to save your search Sign in to your personal 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.

The Ocular Hypertension Treatment Study: Most studies have usedaverage pressures or some kind of algorithm to peg the manometric pressure. Sign in to save your search Sign in to your personal account.

The pressure sensor placed on the outside of the cornea thus measures a pressure that is equal to IOP. Human corneal thickness and its impact on intraocular pressure measures: Detailed mechanical analysis by the inventors demonstrated that variations in any corneal properties over a wide range of values does not influence this pressure measurement, and it showed that even the amount of appositional force applied to hold the tip in place does not affect the pressure reading.

DCT seems to be an appropriate method of tonometry for routine clinical use. Intraocular pressure readings by DCT were computed and displayed by the instrument, thereby reducing possible observer bias.

A piezoelectric pressure sensor 1 is built in the concavity of the tip. In marked contrast, the DCT data were flat across the spectrum of corneal thickness readings, a finding that suggests that this tonometer alone functions independently of corneal thickness. This is still more precise than the GAT readings used to date. Create a free personal account to make a comment, download free article PDFs, sign up for alerts and more.

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Dynamic Contour Tonometry Overcoming the limitations of applanation tonometry. This was a very small sampleand might not be representative of the whole group, or other unknown histopathologicchanges in the anterior part of the cornea may have occurred that were notdetectable by the orbital topography system in these stressed eyes. Pneumatonometry also furnished values lower than true IOP, with the error increasing markedly at higher pressures.

Data points are transferred to a microprocessor-based control unit, whichcomputes and displays the measured pressure.

The contoured tip features a concave surface with a radius of Before each reading, the measuring drum was reset to approximately 2 mm Hg, and the mean of three consecutive readings was recorded. The advantage of an interocular or intraindividual comparison is minimal interference from other nonocular factors in different individuals. Univariate linear regression using DCT as the dependent variable tonoometry GAT as the independent variable gives a slope of 0.

Dynamic contour tonometry: principle and use.

To evaluate intra- and interobserver variability, IOP was measured in eight eyes by four observers. Copyright American Medical Association. Submitted for publication January 8, ; revised May 14, ; accepted June 9, The PTG was rather accurate in the low end of the pressure spectrum comtour deviation, 1.

The chosen contour of the DCT tip will furnish correct measurements defined as measurements with a systematic error of less than 0.

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