Functions of Final Fit
– Interface between OPD-Scan & Excimer
Laser
– Ablation Simulator and Post-Op Map
Display
– Component Splitting (Sph, Cyl and
Irregularity)
– Selection of Treatment type
(OATz, CATz, OPDCAT and Conventional)
– Nomogram Adjustments
– Shot Data File Creation for EC-5000
Ablation Mode (Ver. 1.11)
• OATz
– Large Pupils; reduction of spherical
Aberration
• CATz
– Retreatments; Corneal Irregularities
• OPDCAT
– Maximizing Visual Acuity, Including
internal Aberrations
• Spherical
– Simulation of Conventional Ablations
Profile Algorithms in Final Fit
Central ‘OZ’ Peripheral ‘TZ’ Multipoint
Optimized
Reduce Spherical
Aspherical TZ No
Aberration
OATz
Spherical
Topo-Guided Custom Aspherical
Reduce Corneal Aberration
Yes
CATz
OPD-Guided Custom Reduce Entire Eye Ball
Aspherical Yes
OPDCAT Aberration
1. OATz
A serious concern in Refractive Surgery
with conventional treatment is
“Poor Night Vision”
“Reduce Night Vision
Complaints”
Why night vision complaints
in conventional treatment ?
Post OP -7 D myopia Central part is Plano,
with but…
6.0mm OZ / 7.5mm TZ 3 mm -0.5 D / 5 mm -2.0
D
Why night vision complaints
in conventional treatment ?
• Red Ring :
– rapid Curvature Changes in small area
( = Spherical Aberration )
• The Refraction of Red Ring :
– obstacle to Normal Vision especially in Night Time
→ A cause of Poor Night Vision
Key to solution:
“Transition Zone
Shape”
To Achieve Better
Vision
– Control TZ shape based on Diopter changes
– Push the Red Ring out to the Edge ( or averaging )
– Reduce the Spherical Aberration
– Reduce Night Vision Problem ( Halo & Glare )
– Create Wide Effective Optical Area ( = Optical Area in TZ )
Simulations :
Optimized Aspherical TZ
(OATz)
• Conditions :
– Simulate with PMMA Model Eye 43.27D ( 7.80mm
)
– Sph. : -5D, Cyl. : Non
– OZ / TZ : 5.0 / 9.0mm
– Power control profile #1 to 7
– in Instantaneous map
Red Rings
conditions
Profile#1 Profile#2 Profile#3
69.0µm 76.8µm 84.0µm
Profile#4 Profile#5 Profile#6 Profile#7
93.0µm 101.4µm 109.2µm 116.4µm
Treatment Test on PMMA Model
Eye
Conventional Profile OATz Profile#4
Sph.:-3D Sph.:-3D
OZ/TZ: 6.0/8.0mm OZ/TZ: 5.0/9.0mm
Depth: 54.4µm Depth: 57.6µm
Instantaneous Map, Scale: 0.50D/step, Mid:
Treatment Test on PMMA Model
Eye
Conventional Profile OATz Profile#4
Sph.:-3D Sph.:-3D
OZ/TZ: 6.0/8.0mm OZ/TZ: 5.0/9.0mm
Depth: 54.4µm Depth: 57.6µm
Axial Map, Scale: 0.25D/step, Mid:
OZ/TZ setting for OATz
For OATz (Optimized Aspheric Transition zone),
we recommend to use the widest possible TZ
(OZ +3mm to +4mm) in order to achieve a larger
functional Optical Zone and to reduce
Night Vision problems.
Start with one of the following settings:
• OZ/TZ: 5.0/9.0 mm with Profile #4
• OZ/TZ: 4.5/8.0 mm with Profile #5
2. CATz
OATz
+
Topography based
Irregularity Component
=
CATz
Simulation guide for normal
primary case
1st
dialogue
2nd
dialogue
Resume for the
simulation with Final Fit
Open the simulation screen Check the amount
with attempt correction 0 D of irregular ablation
(Sph./Cyl.)
No Irregularitie
Irregularit s The
y difference
Check the location of between
irregularities corneal
OATz astigmatism
on Cornea on Cornea
+ Internal and
refractive
error of
CATz cylinder can
OPDCAT be a
reference
Decentered LASIK correction
Preoperativ Postoperative
e
Decentered LASIK correction
Preoperativ Postoperative
e
RMS decreased postoperatively
Decentered LASIK correction
Preoperativ Postoperative
e
Wavefront error decreased postoperatively
Decentered LASIK correction
Preoperativ Postoperative
e
Individual higher order aberrations decreased postoperatively
