The New Corvis ST. Evaluation of corneal biomechanical response, tonometry and pachymetry. Biomechanical Response

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Matthew Lawson
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1 The New Corvis ST Evaluation of corneal biomechanical response, tonometry and pachymetry. The revolutionary Corvis ST records the reaction of the cornea to a defined air pulse using a newly developed high-speed Scheimpflug camera (which takes over 4,300 images per second). A highly precise measurement of IOP and corneal thickness can be obtained on the basis of the Scheimpflug images it creates. A video of the 140 images taken within 31 ms after onset of the air pulse is displayed on an integrated touch screen. Based on the parameters that describe the deformation of the cornea it is possible to draw conclusions about its biomechanical properties. Thus the Corvis ST has the potential to provide IOP values which are independent of corneal biomechanical properties. With the new Corvis ST and the diagnostic possibilities it opens up, OCULUS is taking completely new paths in the area of ocular diagnostics. Tonometer Pachymeter Biomechanical Response > Screenshot of the Corvis ST with IOP, corneal thickness and biomechanical response parameters

Biomechanical Response Visualisation of dynamic corneal deformation response images you have never seen before The

These 140 images provide detailed insight into corneal biomechanical response.

and 2 nd applanation length and the curvature radius at the point of maximum deformation (highest concavity).

shorter applanation length and a smaller radius of curvature.

Initial state Applanation 1 Applanation length Highest concavity Deformation Amplitude Peak Distance Radius Applanation

2 Biomechanical Response Visualisation of dynamic corneal deformation response images you have never seen before The high-speed camera records 140 images within 31 ms after onset of the airpulse. These 140 images provide detailed insight into corneal biomechanical response. Information about biomechanical properties can be inferred from the deformation amplitude (see image below), the 1 st and 2 nd applanation length and the curvature radius at the point of maximum deformation (highest concavity). Compared to a stiffer cornea with the same IOP, a softer cornea would lead to a higher deformation amplitude but a shorter applanation length and a smaller radius of curvature. These parameters of corneal deformation open up completely new doors in the field of corneal biomechanics. Initial state Applanation 1 Applanation length Highest concavity Deformation Amplitude Peak Distance Radius Applanation 2 Applanation length Measurement Features of the Corvis ST Deformation amplitude Applanation length Corneal velocity IOP measurement Corneal thickness Scheimpflug images of 1 st and 2 nd applanation and of the highest concavity of the cornea Slow-motion video of the corneal deformation after air pulse

IOP and Pachymetry Measurement of IOP and corneal thickness reaches new level of precision IOP Measurement Mode The new measuring technique uses an ultra-high-speed Scheimpflug camera in combination

Initial studies have confirmed its high degree of reproducibility in comparison to that obtained by Goldmann applanation tonometry and non-contact tonometry 1).

3 IOP and Pachymetry Measurement of IOP and corneal thickness reaches new level of precision IOP Measurement Mode The new measuring technique uses an ultra-high-speed Scheimpflug camera in combination with an air pulse to determine IOP values with great precision. Initial studies have confirmed its high degree of reproducibility in comparison to that obtained by Goldmann applanation tonometry and non-contact tonometry 1). The measurement principle employed here ensures results uninfluenced by such factors as insufficient tear film or patient positioning. Automatic release and specified measurement quality guarantee user-independent data. Up to 6 measurements can be taken, and the average IOP is printed out or displayed. IOP measurements can be corrected with the aid of pachymetry-based correction tables including the Dresden correction table and the new Spoerl correction table, which takes patient age into account. > IOP and corneal thickness measurements using the Corvis ST Pachymetry Mode An integrated Scheimpflug camera enables the Corvis ST to take precise measurements of corneal thickness. Integrated correction tables (Dresden, Ehlers, etc.) also allow for correction of IOP measurements according to central corneal thickness. Additionally, the Corvis ST determines corneal thickness along the horizontal sectional plane including minimal corneal thickness. > Corneal thickness profile over the horizontal sectional plane 1) Hong J, Xu J et al.:. A new tonometer the Corvis STL tonometer: clinical comparison with noncontact and Goldmann applanation tonometers. Invest Ophthalmol Vis Sci ;54(1):659-65

Unique Features, Multiple Applications Applications Determine the true IOP The Corvis ST measures IOP, corneal

Based on these data it has the potential to determine an IOP value that is uninfluenced by corneal biomechanical

High-speed Scheimpflug images A quantum leap in ocular diagnostics Screening for corneal ectasia Corneal ectasia lead

These changes can be analyzed based on deviations in deformation response parameters relative to normal eyes.

4 Unique Features, Multiple Applications Applications Determine the true IOP The Corvis ST measures IOP, corneal thickness and the deformation response of the cornea. Based on these data it has the potential to determine an IOP value that is uninfluenced by corneal biomechanical properties. High-speed Scheimpflug images A quantum leap in ocular diagnostics Screening for corneal ectasia Corneal ectasia lead to changes in the viscoelastic properties of the cornea. These changes can be analyzed based on deviations in deformation response parameters relative to normal eyes. Visualizing the effect of corneal crosslinking Changes in deformation characteristics due to corneal crosslinking can also be measured with the Corvis ST. The Corvis ST has the potential to quantify the effect of crosslinking on the biomechanical properties of the cornea ms ms ms ms ms ms ms ms ms

5 Technical Data OCULUS Corvis ST Tonometer Measurement range Measurement distance Inner fixation light Scheimpflug camera Frame rate Measurement range Pachymeter measurement range Measuring points Source of light Technical specifications Dimensions (W x D x H) Weight Max. power consumption Voltage Frequency in accordance with Medical Device Directive 93/42/EEC mm in 270 mm 10.7 in Oculus is certified by TÜV according to DIN EN ISO mmhg 11 mm (0.4 in) Red LED 4,330 images per sec 8.5 mm (0.3 in) horizontal coverage 200-1,200 μm 576 per image (80,640 per examination) Blue LED (470 nm UV free) 270 x 520 x mm (10.7 x 20.5 x in) 14 kg (30.8 lbs) 49.5 W 110/220 VAC Hz 520 mm 20.5 in OCULUS Optikgeräte GmbH Postfach Wetzlar GERMANY Tel Fax export@oculus.de OCULUS USA, sales@oculususa.com OCULUS Asia, info@oculus.hk OCULUS Czechia, oculus@oculus.cz OCULUS Iberia, info@oculus.es OCULUS Poland, biuro@oculus.pl 20/0313/EN/Ha The availability of products and features may vary by country, and OCULUS reserves the right to change product specifications and design. P/72100/EN

6 OCULUS Corvis ST Corneal Visualization Scheimpflug Technology We focus on progress

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