ziemer PASCAL DCT Gebrauchsanweisung Seite 2

PASCAL DCT: Directions for use
IOP measured with PASCAL in comparison with Goldmann
PASCAL's outstanding accuracy was proven in an in vivo study where 60 eyes were measured during
cataract surgery. A mean difference between PASCAL and true IOP of only -0.2 mmHg was found. In
many other studies PASCAL's precision has been proven to be superior to the Goldmann Tonometer.
PASCAL's IOP measurements are fairly independent of any corneal properties, such as central corneal
thickness (CCT) and corneal rigidity. The latter was shown to have an even greater influence on
Goldmann tonometry (GAT) than CCT; however it cannot be measured directly. Therefore correction
tables based only on CCT, as well as conversions of IOP values from GAT to PASCAL are neither valid
nor possible in individuals.
Although individual values cannot be converted, on average PASCAL values are approximately 1.7
mmHg higher than a GAT-value. The difference stems from the fact that PASCAL is calibrated to real
pressure whereas the GAT scale was calibrated in 1954 according to calculations slightly
underestimating the real pressure. (Fig.2)
A PASCAL IOP reading cannot be converted to a GAT-IOP value for individuals. The difference of IOP
between GAT and PASCAL is an indirect measure for corneal rigidity.
For PASCAL, the traditional 21 mmHg GAT cut off limit would be at approximately 23 mmHg, based
on the average 1.7 mmHg difference between Pascal and GAT. (Fig.2)
PASCAL does not only record a snapshot reading of IOP as does GAT. Instead, PASCAL detects the full
IOP curve obtained over the measurement cycle (red curve in Fig.1).
Fig.1: In vivo comparison of a PASCAL (red) with a
manometric (black) IOP measurement.
IOP is an approximately sinusoidal curve pulsating with the heartbeat. PASCAL IOP is by definition
the diastolic IOP, and the Ocular Pulse Amplitude (OPA) is the difference between systolic and
diastolic IOP (Fig.1). PASCAL is measuring a minimum of 3 IOP cycles which takes approximately 3 to
5 seconds. This allows PASCAL to achieve its superior reliability and to acquire additionally the heart
rate and OPA. The full IOP curve (Fig.1) can be printed with the optional printer or transferred to a
PC. From the curve, PASCAL automatically calculates IOP, OPA and Quality.
DISCLAIMER OF LIABILITY
Ziemer Ophthalmic Systems Ltd excludes all liabilities concerning this product unless restricted by applicable law. Particularly Ziemer
Ophthalmic Systems Ltd shall not be liable for any injury or damage suffered by a patient as a result of any application technique used,
neither as a result of prescription, selection or use of this product for a particular patient. Every operator of this product takes full
responsibility for an appropriate prescription, selection and proper use of this product as well as for the application technique used for the
particular patient.
Ambient Conditions:
Storage:
Temperature: -10°C to +55°C / +14°F to +131°F
Relative humidity: 10% to 95%
Air pressure: 700 hPa to 1060 hPa
Doc. 6100-50-0001-22
Fig.2: Normal distribution of 2175 people; IOP
measured with PASCAL and GAT.
Working:
+10°C to +35°C / +50°F to +95°F
30% to 90%
800 hPa to 1060 hPa
2/8
PASCAL DCT: Directions for use
IOP measured with PASCAL in comparison with Goldmann
PASCAL's outstanding accuracy was proven in an in vivo study where 60 eyes were measured during
cataract surgery. A mean difference between PASCAL and true IOP of only -0.2 mmHg was found. In
many other studies PASCAL's precision has been proven to be superior to the Goldmann Tonometer.
PASCAL's IOP measurements are fairly independent of any corneal properties, such as central corneal
thickness (CCT) and corneal rigidity. The latter was shown to have an even greater influence on
Goldmann tonometry (GAT) than CCT; however it cannot be measured directly. Therefore correction
tables based only on CCT, as well as conversions of IOP values from GAT to PASCAL are neither valid
nor possible in individuals.
Although individual values cannot be converted, on average PASCAL values are approximately 1.7
mmHg higher than a GAT-value. The difference stems from the fact that PASCAL is calibrated to real
pressure whereas the GAT scale was calibrated in 1954 according to calculations slightly
underestimating the real pressure. (Fig.2)
A PASCAL IOP reading cannot be converted to a GAT-IOP value for individuals. The difference of IOP
between GAT and PASCAL is an indirect measure for corneal rigidity.
For PASCAL, the traditional 21 mmHg GAT cut off limit would be at approximately 23 mmHg, based
on the average 1.7 mmHg difference between Pascal and GAT. (Fig.2)
PASCAL does not only record a snapshot reading of IOP as does GAT. Instead, PASCAL detects the full
IOP curve obtained over the measurement cycle (red curve in Fig.1).
Fig.1: In vivo comparison of a PASCAL (red) with a
manometric (black) IOP measurement.
IOP is an approximately sinusoidal curve pulsating with the heartbeat. PASCAL IOP is by definition
the diastolic IOP, and the Ocular Pulse Amplitude (OPA) is the difference between systolic and
diastolic IOP (Fig.1). PASCAL is measuring a minimum of 3 IOP cycles which takes approximately 3 to
5 seconds. This allows PASCAL to achieve its superior reliability and to acquire additionally the heart
rate and OPA. The full IOP curve (Fig.1) can be printed with the optional printer or transferred to a
PC. From the curve, PASCAL automatically calculates IOP, OPA and Quality.
DISCLAIMER OF LIABILITY
Ziemer Ophthalmic Systems Ltd excludes all liabilities concerning this product unless restricted by applicable law. Particularly Ziemer
Ophthalmic Systems Ltd shall not be liable for any injury or damage suffered by a patient as a result of any application technique used,
neither as a result of prescription, selection or use of this product for a particular patient. Every operator of this product takes full
responsibility for an appropriate prescription, selection and proper use of this product as well as for the application technique used for the
particular patient.
Ambient Conditions:
Storage:
Temperature: -10°C to +55°C / +14°F to +131°F
Relative humidity: 10% to 95%
Air pressure: 700 hPa to 1060 hPa
Doc. 6100-50-0001-22
Fig.2: Normal distribution of 2175 people; IOP
measured with PASCAL and GAT.
Working:
+10°C to +35°C / +50°F to +95°F
30% to 90%
800 hPa to 1060 hPa
2/8