Paragon CRT Dual Axis User Manual

e Paragon CRT® Proximity Control Technology™ and manufacturing
system was designed to allow for independent modulation of the three zones
of the lens: Base Curve (BC) Return Zone Depth (RZD), and Landing Zone
Angle (LZA). e Base Curve radius controls treatment of the refractive
error and remains spherical and unchanged. In the Paragon CRT Dual Axis®
version, the Return Zone Depth (RZD) can be varied in selected meridians
to compensate for the peripheral corneal elevation dierences of an eye.
Correspondingly, the Landing Zone Angle, by itself, may be varied in a
second axis while the base curve and return zone depths are unchanged or
both RZD and LZA may be varied in the second meridian to compensate for
the peripheral corneal slope meridional dierences of an eye.
In other words, when tting a Paragon CRT Dual Axis® design, the BC
remains constant throughout the treatment process, unless there is a need
to correct untreated or residual power.
Using this standard CRT lens example: BC 8.7 RZD 550 LZA -33
e possible parameter alternatives for the Dual Axis product are:
1. e RZD could have a second value and the LZA
would remain a single parameter (8.7/550 & 600/-33)
2. e LZA could have a second value and the RZD
remains a single parameter (8.7/550/-33 & -34)
3. e RZD and LZA could both have second values (8.7/550 & 600/-33 & -34)
Corneal Topography and CRT Dual Axis
®
Prescribing
It is common for Placido-based corneal topographers to directly measure curvature
data out to about 9-10 mm. is curvature data can be reconstructed into height data
and represented as an ELEVATION MAP. Elevation maps illustrate relative height
deviations from the best t reference sphere for a particular cornea in MICRONS.
On a cornea with asymmetric peripheral saggital depth, a relative deviation from a
reference sphere (RED shaded areas) can be observed between the meridian having
the greatest elevation above the reference sphere and the meridian having the lowest
elevation below the reference sphere (BLUE shaded areas). By placing the cursor

Paragon CRT Dual Axis Specifications

General

Brand	Paragon
Model	CRT Dual Axis
Category	Medical Equipment
Language	English