Ziemer Ophthalmology
CPT Code 0198T (Measurement of Ocular Blood Flow
by repetitive intraocular pressure sampling)
Dynamic contour Tonometry (DCT) is a novel measuring technique, which was designed to more
accurately measure IOP, largely independent of the cornea’s thickness, curvature or biomechanical
properties. In vitro and in vivo invasive studies have demonstrated a nearly linear relationship of DCT
to manometric IOP, independent of corneal thickness or curvature. Additionally, DCT values have been
shown to remain unchanged in individuals, before and after LASIK surgery. While this device is similar
in appearance to Goldmann Applanation Tonometry, the PASCAL® is not a variable force tonometer.
PASCAL implements a miniature piezoelectric pressure sensor, which is embedded within a contourmatched
tonometer tip. The tonometer tip rests on the cornea with a constant appositional force of one
gram. The contour matched tip has a concave surface that approximates the cornea’s shape when no
external forces are acting on it. Once a portion of the central cornea has taken up the shape of the tip,
the integrated pressure sensor begins to acquire pressure readings.
Because the PASCAL® measures IOP 100 times per second, a pulse wave is generated, that is
reflective of heart rate and the mean difference between diastolic and systolic IOP. This value is called
Ocular Pulse Amplitude (OPA). OPA is reflective of the relative quality of ocular blood flow.
Investigators have shown that those individuals with lower than average OPA have a greater likelihood
of being glaucomatous. This relationship seems to be particularly significant in patients with normal
tension glaucoma.
This information may have value to the clinician in assessing the early onset of disease caused by
compromised blood supply to the eye. In particular, patients who have normo-tensive glaucoma (NTG)
may have insufficient blood perfusion. Studies have shown that OPA is lower in patients with glaucoma,
which supports the hypothesis that vascular factors are associated with this disease. Low OPA has also
been shown to correlate with Drance hemorrhage.
Effective January 1, 2009, Category III CPT Code 0198T (measurement of ocular blood flow by
repetitive intraocular pressure sampling, with interpretation and report) has been assigned. Measuring
the ocular pressure curve with the PASCAL DCT is therefore now a billable procedure.
To make documenting the measurement easy, Ziemer has created the PASCAL TRS Tonometry
Recording System. It combines the proven PASCAL Dynamic Contour Tonometer with an elegant
subnotebook PC. The PC receives PASCAL data over a Bluetooth link and generates a diagnostic
report that can be appended to the patient’s electronic medical record and serves to document the
procedure for billing purposes.
For more information on the PASCAL TRS and on the specifics of billing procedures, go to
www.ziemergroup.com
Please also refer to a detailed FAQ issued by the Corcoran Consulting Group:
http://www.corcoranccg.com/View.aspx/2255/Ziemer-USA--Inc-
Contact:
Elliot M. Kirstein, OD, FAAO; PASCAL Sales Director - Ziemer USA.
Phone 513.530.0440; mobile 513.659.1916
[email protected]
About Ziemer:
Ziemer Ophthalmic Systems, a Ziemer Group company, is domiciled in Port (Switzerland). Ziemer develops, manufactures, and
markets surgical and diagnostic devices for the ophthalmic and optometric market. Main activities include corneal and refractive
surgery, and diagnostic tools for refractive and Glaucoma specialists. Founded in 1998, Ziemer Group currently has 125 employees
and actively markets its products world-wide. Besides its Switzerland-based headquarters, Ziemer has a marketing subsidiary in the
USA. The Ziemer product portfolio includes the FEMTO LDV™ Femtosecond Surgical Laser, the AMADEUS II® Comprehensive
Microkeratome System, the GALILEI™ Dual Scheimpflug Camera, and the PASCAL® Dynamic Contour Tonometer.
Ziemer USA, Inc. is a fully owned subsidiary of Ziemer Group. It markets all Ziemer Group products in the USA.
The PASCAL® has been engineered and is manufactured by SMT AG, a Ziemer Group Company, and is marketed and
distributed by Ziemer Ophthalmic Systems AG and its worldwide network of authorized distributors. PASCAL® is a registered
trademark of SMT AG (a Ziemer Group Company).