1
Surgically induced aberrations and optical performance
Susana Marcos, Ph.D.Instituto de Optica, CSIC
Wavefront Sensing Meeting. San Francisco. Feb.2003 Aberrations &Optical performance
Corneal Refractive surgery(LASIK)
Where does the optical degradation arise from?
Cataract surgery
Aberrations
Simpler case: defocus (myopia)
.
The eye suffers from aberrations of higherorder than defocus
Aberrations
Aberrated wavefront spherical wavefront
WAVE ABERRATION
What is the wave aberrationWhat is the wave aberration??Wave aberration:phase distortions at thepupil plane
topographic map
? m
2
???
??
??),(1
'W
Rx
p
???
???? ),(1' W
Ry
p
(?0,? 0)
(? x’,? y’)(?0,? 0)
Mathematical expressionMathematical expression
The deviations at the plane of the retina are proportional to the derivatives of the wave aberration
ZernikeZernike Polynomial expansionPolynomial expansion
= Z2
+ Z3 + Z3 + Z3 + ...
+ Z4 +...+ Z7 + Z7
+2 + Z2-2
3 1 -1
0 -5 -7
Root mean square Root mean square wavefrontwavefront errorerror::
— mean?2
RMS =RMS =
Optical quality metricsOptical quality metrics Wavefront aberration
Image of a point (PSF)
Modulation Transfer (MTF)
MethodsMethodsTotal aberrations:
LRTCorneal aberrations:
Topographer +
Custom software
Ocular biometryIOL master(OCT +Slit lamp)
2nd 2nd generationgeneration LRTLRT
Pupil Pupil monitoringmonitoring
FixationFixationchannelchannel
3
Aberratedwavefront
Laser Ray Tracing: Basic ConceptLaser Ray Tracing: Basic Concept
-150 -100 -50 0 50
-100
-50
0
Spot diagram Pupil Sampling
Data collectionData collection
Elevation map
Corneal topography
Ray Tracing
Corneal aberrations
Corneal aberrationsCorneal aberrations
Barbero et al. J.Refrt. Surg (2002)
Zernike Coefficient #
Ze
rnik
e A
mp
litu
de(
µm
)
Total CoefficientsCorneal Coefficients
Patient A: OD
0 5 10 15 20 25 30 35
-2.5
-1.5
-0.5
0.5
1.5
-3.0
-2.0
-1.0
0.0
1.0
Zernike Coefficient #
Ze
rnik
e A
mp
litu
de(
?m
)
Patient A: OI
0 5 10 15 20 25 30 35
-2.5
-1.5
-0.5
0.5
1.5
-3.0
-2.0
-1.0
0.0
1.0
ODTotal Corneal
OSTotal Corneal
KeratoconusKeratoconusBarbero, Marcos, Merayo, Moreno. J. Refract. Surg. (2002)
Total CoefficientsCorneal Coefficients
Zernike Coefficient #0 5 10 15 20 25 30 35-1.5
-0.5
0.5
-1.0
0.0
Ze
rnik
e A
mp
litu
de(
µm
)
Patient B: OD
Corneal
Total
AphakicAphakic Barbero, Marcos & Merayo. J. Cat. Refract. Surg. (2002)
= +
Total Corneal Internal
Aberrations and Cataract Surgery
4
?9 eyes from 7 subjects ?mean age: 70.58 ± 8.96?Measurements at least 2 months post-surgery?6 eyes also before surgery
?Phacoemulsification: 4.1 mm superior incision (no suture)?Spherical IOLs?Powers from 0 to 26 D.
Patients Patients ((cataract surgerycataract surgery))
Eye #1-IOL 0 D
Total Corneal Internal
Eye #4-IOL 21 Dp
Eye #4-IOL 23 Dp
Eye #9-IOL 26 D
Total Corneal Internal
Total, Total, cornealcorneal & & internal aberrationsinternal aberrationsPOST CATARACT POST CATARACT surgerysurgery
0 D 14 D 16.5 D 21 D 23 D
23 D 23 D 25.5 D 26 D
IOL IOL wave aberrations wave aberrations in vivoin vivo
? m
Barbero , Marcos, & Jimenez-Alfaro , JOSA A (2003)
00,10,20,3
0,40,5
0,60,70,80,9
Total Corneal Internal
RM
S 3
rd&
Hig
her
(mic
rons
)
Pre
Post
Young
ComparisonComparison total total aberrations aberrations PRE/POST/YOUNG control PRE/POST/YOUNG control group group
Barbero , Marcos, & Jimenez-Alfaro , JOSA A (2003)
Pre-cataract surgery Post-cataract surgery Young control
Age= 67RMS=0.63 ? m
Age= 68RMS=0.85 ? m
Age= 28RMS=0.15 ? m
? m
Why the aberrations of pseudophakic Why the aberrations of pseudophakic patientspatients are are higher than those of young higher than those of young eyeseyes?? ?Increase of corneal aberrations with age, and
increase of corneal aberrations by incision
?Aberrations of the IOL
?Tilt/decentrations of IOL
?No balance internal/corneal aberrations
Various reasonsVarious reasons::
5
Corneal aberrationsCorneal aberrationsIncrease of corneal aberrations with age
Oshika et al.1999Guirao et al. 2000
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
Eye #2 Eye #11 Eye #14
RM
S 3
rd &
Hig
her
(mic
rons
)
PRE POST
Slight increase of corneal aberrationswith surgery
1 mm 0.8 mm
Camara objetive Methachrylate
wall IOL
5 mm
Effective aperture: 4.22 mm
Nikkor camera objective Water cell
Movingartificial retinaIOL
MeasuringMeasuring IOL IOL aberrationsaberrations in in vitrovitro
IOL IOL wave aberrations wave aberrations in in vitrovitro
0 D 12 D 23 D16 D
Barbero , Marcos, & Jimenez-Alfaro , JOSA A (2003)
Ideal cornea(for in vitro measurements comparisons)
Or individual cornea(for in vivo measurements comparisons)
Predicted aberrations of thePredicted aberrations of the IOLIOL
0
0,1
0,2
0,3
0,4
0,5
0,6
3rd&Higher 3rd 4rd&Higher Astigm
RM
S (
mic
ron
s) In vivo
Ex vivo
IOL IOL AberrationsAberrations: in vivo : in vivo and and in in vitrovitro Spherical aberration of theSpherical aberration of the IOLIOL
Positive spherical aberration!!
0 5 10 15 20 25 30IOLPower (D)
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
In vivo
In vitro
Simulation
sphe
rica
l abe
rrat
ion
(mic
rons
)
6
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Eye #7 Eye #8 Eye #9 Eye #10 Eye #11 Eye #14 Eye #15
In vivo
Simulations
Spherical aberrationSpherical aberration: in vivo/: in vivo/simulatedsimulated
sphe
rica
l abe
rrat
ion
(mic
rons
)
0
0.5
1
1.5
2
3rd&higher 3rd 4rd&higher 4rd
RM
S (m
icro
ns)
In vivoIn vitro
Third order aberrationsThird order aberrations: : TiltsTilts
0 deg +4 deg
0.24 ? m 0.48 ? m
In vitro on/off axis
-0.6 -0.4 -0.2 0.0 0.2 0.4 0.6Decentration (mm)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
3rd
ord
er R
MS
(mic
ron
s)
2-deg tilt (x axis)
Horizontal decentration
Vertical decentration
-4 -2 0 2 4Tilt (deg)
0.00
0.05
0.10
0.15
0.20
3rd
ord
er
RM
S (
mic
rons
)
horizontal tilt
vertical tilt
0.5-mm horizontal decentration
Third order aberrationsThird order aberrations: : Simulated Simulated TiltsTilts & & decentrationsdecentrations
00,05
0,10,15
0,20,25
0,30,35
Post YoungRM
S s
ph
eric
al a
ber
rati
on
TotalCornealInternal
CornealCorneal / / Internal aberrationInternal aberration balancebalance
Wavefront aberration
Image of a point (PSF)
Modulation Transfer (MTF)
?In vitro MTF measurements
? In vivo double-pass MTF measurements
Optical performance Optical performance in in terms of terms of MTFMTF
7
0 10 20 30 40 50Spatial Frequency (c/deg)
0.1
1.0
MTF
In vitro (Acrysof)
Simulation (Acrysof)
Oshika et al. (Acrysof)
Norrby et al. (PMMA)
IOL’s MTF (in IOL’s MTF (in vitro and fromvitro and from designdesign))
? = 3 mm0 10 20 30 40 50 60 70 80 90
Spatial Frequency (c/deg)
0.0
0.1
1.0
MTF
Young eyes
Post surgery eyes
Guirao double-pass
Artal double-pass
Ocular MTFOcular MTF
? = 4 mm
ConclusionConclusion
IOLs elliminate the degradation IOLs elliminate the degradation produced produced by by scatteringscattering, , but but do do not not restore optical quality to young eyes’ restore optical quality to young eyes’ valuesvalues........
THERE IS ROOM FOR IMPROVEMENTTHERE IS ROOM FOR IMPROVEMENT
Age= 23.2RMS= 0.66 ? m
Age= 40.1RMS= 0.87 ? m
Age= 50.2RMS= 0.80 ? m
Age= 62,9RMS= 1.04 ? m
? mNormal aging
Young control
Age= 28RMS=0.15 ? m
? = 7.3 mm
Post-cataract surgery
Age= 68RMS=0.85 ? m
? m
? = 5 mm
McLellan, Marcos & Burns, IOVS, 2000
Optical vs visual performanve
spatial frequency (c/deg)0 1 0 20 30 40 50 60 70
0.0
0.2
0.4
0.6
0.8
1.0
MT
F
Optical vs visual performanve
spatial frequency (c/deg)0 1 0 20 30 40 50 60 70
0.0
0.2
0.4
0.6
0.8
1.0
MT
F
spatial frequency (c/deg)0 1 0 2 0 30 40 50 60 70
0.0
0.2
0.4
0.6
0.8
1.0
CSF
8
What is the CSF?
spatial frequency (c/deg)
CSF
2 4 6 8 210spatial frequency (c/deg)
0.0
0.5
1.0
1.5
2.0
2.5
Lo
g C
ontr
ast S
ensi
tiv
ity
Visual Visual performance with IOLsperformance with IOLs
Young eyesOld normal eyesEyes with IOL’s
Adapted from Navarro, Ferro, Artal & Miranda, 1993
Potential solution
Aspheric IOLsAspheric IOLsWith negative spherical aberrationWith negative spherical aberration, , ideally ideally
matching the matching the individual corneaindividual cornea
Drawbacks
Tilts and decentrations Tilts and decentrations more more detelerious than detelerious than for spheric IOLs for spheric IOLs ((AtchisonAtchison, 1989), 1989)
Presence of aberrations becomes attenuated by...
Smaller pupils
Increased depth-of-field (i.e. Multifocality)
Will the benefits of aspheric IOLs exceed their potential drawbacks?
Is an aberration-free eye really needed in an eye without accommodative response?
Other questions
Should we aim toward a customized intraocular(cataract) surgery?
http://patient. isrs.org
Moreno-Barriuso et al. IOVS; Marcos 2001
Optical aberrations and standard LASIK refractive surgery
9
www.lasersite .com
Patients Patients ((myopicmyopic LASIK)LASIK)
?22 eyes from 12 subjects ?mean age: 28?5?Spherical equivalent: -2.5 thru –13 D?No ocular or retinal condition?Measurements <1 mo. before and >1 mo. after surgery
?Flying spot Technolas 217-C (B&L surgical)?Hansatome microkeratome?Optical zone: 6 mm. Transition zone: 9 mm
gacod
CornealTotal
Pre-LASIK
Post-LASIK
RMS=0.83 ? m RMS=0.87 ? m
RMS=2.67? m RMS=2.66 ? m
Marcos et al. IOVS (2001)
ahcoi
CornealTotal
Pre-LASIK
Post-LASIK
RMS=0.54 ? m RMS=0.35 ? m
RMS=1.95 ? m RMS=1.93 ? m
Marcos et al. IOVS (2001)ahcod
CornealTotal
Pre-LASIK
Post-LASIK
RMS=0.54 ? m RMS=0.61 ? m
RMS=1.40 ? m RMS=1.49 ? m
mmaoi
CornealTotal
Pre-LASIK
Post-LASIK
RMS=0.74 ? m RMS=0.71 ? m
RMS=1.87 ? m RMS=2.36 ? m
Marcos et al. IOVS (2001)
3rd 3rd and higher orderand higher order
0
0.5
1
1.5
2
2.5
3
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
EYE #
RM
S (
?m
)
PRERE--LASIKLASIKPOST-LASIK
Moreno-Barriuso et al. IOVS (2001)
TOTAL TOTAL aberrationsaberrations
10
Average data
00.20.40.60.8
11.21.41.61.8
3rd - 7thorder
3rd order 4rth order 5th &higherorders
n= 22n= 22
3rd-7th
orders3rd
order4th
order5th & higher
orderssphericalaberration
PREPRE--LASIKLASIKPOSTPOST--LASIKLASIK
p=0.003 p=0.0028 p<0.0001 p<0.0001p=0.17** ** ** **
RM
S (?
m)
Moreno-Barriuso et al. IOVS (2001)
-0.5
0
0.5
1
1.5
2
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Tot-pre
Tot-post
Increase of TOTAL Spherical Aberration with LASIK
Spherical aberration
eye #
04Z
? m
Marcos et al. IOVS (2001)
The higher the pre-op spherical error, the largerspherical aberration is induced
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
r = 0.76
14121086420PRE-LASIK SPHERICAL ERROR (D)
PO
ST-
LAS
IK S
PH
ER
ICA
L A
B.(?
m)
-0.5
0
0.5
1
1.5
2
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Corn-pre
Corn-post
Increase of CORNEAL Spherical Aberration with LASIK
Spherical aberration
eye #
04Z
? m
Marcos et al. IOVS (2001)
Why spherical aberration increasesWhy spherical aberration increases??
Q>0
Q=0
Q<0
Because corneal asphericity changes from negative values (prolate cornea) to negative values (oblate cornea). Holladay (1999)
Analytical models provide controversial results:
No approximation
Equation for corneal asphericity after refractive surgeryJ.R. Jimenez et al. J. Refract. Surg. In press
CONCLUSIONS: This equation…. Explains the increased spherical aberration after refractive surgery.
Parabolic approximation
11
Munnerlyn formula simulations vs experimental data Munnerlyn ablation depth
POST corneal height
PRE corneal height
POST experimental -simulated
mmmm
POST CorneaExperimental SimulatedR=8.74
Q=0.35R=8.98Q=-0.075
R=9.04Q=0.54
R=9.19Q=0.14
R=9.68Q=1.82
R=9.40Q=0.026
#5
#6
#14
-2-1012345
-2 -2,8 -3,3 -3,5 -5,4 -6,3 -6,3 -7,3 -7,3 -7,5 -7,5 -8,9 -12Spherical Equivalent (D)
as
ph
eri
cit
y
ChangeChange in in corneal asphericity with corneal asphericity with myopicmyopic LASIKLASIK
Q<0 Q>0
-2-10123
45
-2 -2,8 -3,3 -3,5 -5,4 -6,3 -6,3 -7,3 -7,3 -7,5 -7,5 -8,9 -12
Spherical Equivalent (D)
asp
her
icity
Post-Q (Munnerlyn ) Marcos, Cano & Barbero (2003)
Compared to Munnerlyn algorithmCompared to Munnerlyn algorithm
Pre- QPost- Q
-2
-1
0
1
2
3
4
5
-2 -2.8 -3.3 -3.5 -5.4 -6.3 -6.3 -7.3 -7.3 -7.5 -7.5 -8.9 -12spherical equivalent (D)
asp
her
icit
yChangeChange in in corneal asphericity with corneal asphericity with myopicmyopic LASIKLASIKCompared to Munnerlyn Parabolic approximation Compared to Munnerlyn Parabolic approximation
Pre- QPost- QPost-Q (Parabolic Munnerlyn ) Marcos, Cano & Barbero (2003)
Radial Radial changes of absorbtion efficiencychanges of absorbtion efficiency
?Changes in spot area
?Reflection losses?KoI
K? I
Mrochen & Seiler, 2001Jiménez et al., 2002
Changes in absorbtion
Increased asphericity
Why corneal asphericity increasesWhy corneal asphericity increases??
Does the ablation profile really follow the Munnerlyn equation, or an approximation ?
Is the discrepancy due to biomechanical changes?
Is the ablation profile properly transferred onto the cornea?
CRITICAL FOR CRITICAL FOR CUSTOMIZED/OPTIMIZED CORRECTIONCUSTOMIZED/OPTIMIZED CORRECTION
12
-16.0 -12.0 -8.0 -4.0 0.0pre-op spherical error (D)
-1.0
0.0
1.0
2.0
3.0Corneal
Total
Internal
Indu
ced
Sph
eric
al a
berr
atio
n(?
m)
INDUCED corneal, total & internal aberration
Marcos et al. IOVS (2001)
PRE POST
Can the change of ray convergence on the crystalline lens be the cause of the measured change in internal aberrations?
Explaining the changes in the internal optics
Computer simulation
Internal aberration= Total – Corneal
-16 -12 -8 -4 0Pre-op spherical error (D)
-0.1
0.0
0.1
0.2Simulated Internal POST-PRE
Ind
uce
d in
tern
al
sph
eric
al a
ber
rati
on
(?m
)
Real cornealanterior surface
Model crystalline lens
Simulated total aberrations
Toward positivevalues!
Intraocularpressure
Laserablation
Can be changes in the posterior corneal surfacebe the cause of shift of internal aberrations to negative values?
Explaining the changes in the internal optics
Comparing with scanning slit topography data
Previous studies using Orbscan showed changesin the posterior corneal surface after LASIK
Naroo & Charman (2000)Baek et al. (2001)Bruno et al. (2001)Seitz et al. (2001)
Do those changes in the posterior corneal shapepredict our change in posterior spherical aberration?
Spherical aberrationof posterior cornea inducedby LASIK
Ray Tracing Seitz et al. (2001):Change in central power:
-6.28 D -6.39 DChange in asphericity (P)
0.98 -1.14 -0.103 ? m
This study. Marcos et al. (2001) -0.110 ? m
13
Most changes in the spherical aberration of the internal optics with LASIK seem to be due to the posterior corneal surface
-16 -12 -8 -4 0pre-op spherical error (D)
-1.5
-1.0
-0.5
0.0
0.5
PO
ST-
PR
E in
tern
al
sphe
rica
l abe
rrat
ion
(D)
Experimental
Convergence
The role of pre-LASIK internal optics
pre
post
Total Corneal Internal
amaodMarcos et al. IOVS (2001)
Spherical aberrationSpherical aberration in in myopic eyesmyopic eyes
-0.5
-0.3-0.1
0.10.30.5
0.70.9
1.11.3
1.5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
-0.5
-0.3
-0.1
0.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
1 2 3 4 5 6 7 8 9 10 11 12 1 3
Low myopes (-0.25 – -4.1 D)
TotalCorneal
Moderate myopes (-4.4 – -7 D)
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1 2 3 4 5 6 7 8 9 1 0 11 12 13 1 4 15 16
High myopes (-7.1 – -15D)
sph.
ab
erra
tio
n c
oef
f. (?
m)
Marcos et al. OSA 2001
-16 -12 -8 -4 0spherical error (D)
-1.0
0.0
1.0
co
eff 1
2 (m
icro
ns
)
Total
Internal
Corneal
Total
Corneal
Internal
(p=0.95)
(p=0.001)
(p=0.009)
Marcos et al. OSA 2001
Spherical aberrationSpherical aberration in in myopic eyesmyopic eyes
AberrationsAberrations in in myopic eyesmyopic eyes
-0.7 D -6.5 D -11 D
RMS=0.39 ? m RMS=0.63 ? m RMS=0.98 ? m
0 4 8 12Spherical error (D)
0
RM
S 3
rdor
der
and
high
er (?
m)
0 4 8 12Spherical error (D)
0
1
2
RM
S 3
rd o
rder
and
hig
her
(mm
)
4
-3
2
0-1.5
? m
Marcos et al. 2000
n=53
r= 0.42 p=0.0014
Hyperopic LASIK Refractive Surgery
The central cornea is made steeper than the periphery, by removing tissue around the central area
14
Patients Patients ((hyperopichyperopic LASIK)LASIK)
?13 eyes from 7 subjects ?mean age: 32?11?Spherical equivalent: +1.25 thru +3.5 D?No ocular or retinal condition?Measurements <1 mo. before and >1 mo. after surgery
?Flying spot Technolas 217-C (B&L surgical)?Hansatome microkeratome
http://www.lasersite .com
Total Corneal
Pre
Post
RMS= 0.34 ? m
RMS= 0.82 ? mRMS= 1.13 ? m
RMS= 0.63 ? m
cssoi
RMS= 1.00 ? m
RMS= 0.93 ? mRMS= 0.94 ? m
RMS= 0.67 ? m
cssod
Total Corneal
Pre
Post
RMS= 0.52 ? m
RMS= 1.14 ? mRMS= 1.25 ? m
RMS= 0.50 ? m
ifroi
Total Corneal
Pre
Post
RMS= 0.81 ? m
RMS= 1.64 ? mRMS= 1.92 ? m
RMS= 0.70 ? m
cfaoi
Total Corneal
Pre
Post
RMS= 0.75 ? m
RMS= 2.10 ? mRMS= 2.10 ? m
RMS= 0.75 ? m
cfaod
Total Corneal
Pre
Post
15
0
0.2
0.4
0.6
0.8
1
1.2
1 2 3 4 5 6 7 8 9 10 11 12 13
Eye #
RM
S (
?m)
TOTALCORNEAL
AberrationsAberrations in in hyperopic eyeshyperopic eyes
3rd and higher order aberrations
PrePre-- opopLlorente, Marcos, Barbero & Merayo, IOVS (Suppl), 2002
AberrationsAberrations in in hyperopic eyeshyperopic eyes
spherical aberrations
PrePre-- opop
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
1 2 3 4 5 6 7 8 9 10 11 12 13Eye #
Coe
ff.Z 4
0 ( ?m
)
TOTALCORNEAL
Llorente, Marcos, Barbero & Merayo, IOVS (Suppl), 2002
Spherical aberration
20
22
24
26
28
0 1 2 3 4 5 6 7 8|Spherical Error| (D)
Ax
ial
Le
ng
th (
mm
)
Myopes
Hyperopes
MyopesMyopes/ / hyperopichyperopic eyeseyesAxial length
-0.6-0.4-0.2
00.20.4
0 1 2 3 4 5 6 7 8|Spherical Error| (D)
Asp
heri
cit
y
Corneal asphericity
Llorente, Marcos, Barbero & Merayo, IOVS (Suppl), 2002
0
0.5
1
1.5
2
2.5
1 2 3 4 5 6 7 8 9 10 11 12 13Eye #
RM
S (
?m)
PRE-LASIK HPOST-LASIK H
Change ofChange of TOTAL TOTAL aberrations with aberrations with hyperopichyperopic LASIKLASIK
3rd and higher order aberrations
Llorente, Marcos, Barbero & Merayo, IOVS (Suppl), 2002
-1,2-1,0-0,8-0,6-0,4-0,20,00,20,40,60,8
1 2 3 4 5 6 7 8 9 10 11 12 13
RM
S (
m)
PRE-LASIK HPOST-LASIK H
Spherical aberration
Change ofChange of TOTAL TOTAL aberrations with aberrations with hyperopichyperopic LASIKLASIK
Llorente, Marcos, Barbero & Merayo, IOVS (Suppl), 2002
-1,4-1,2-1,0-0,8-0,6-0,4-0,20,00,20,40,60,8
1 2 3 4 5 6 7 8 9 10 11 12 13
Eye #
Coe
ff.
Z40
?????
m?
PRE-LASIK HPOST-LASIK H
Change ofChange of CORNEAL CORNEAL aberrations with aberrations with hyperopichyperopic LASIKLASIK
Spherical aberration
Llorente, Marcos, Barbero & Merayo, IOVS (Suppl), 2002
16
Myopic LASIK
Hyperopic LASIK
Slope= 0,1701R= 0,86
-2-1,5
-1-0,5
00,5
11,5
2
0 2 4 6 8 10 12 14
Corneal
|Pre-LASIK Spherical Error| (D)
Slope= -0,23R= 0,60
-1,5
-1-0,5
00,5
11,5
2
0 2 4 6 8 10 12 14
Total
|Pre-LASIK Spherical Error| (D)
Slope= 0,091R= 0,63
Slope= -0,057R= 0,24
Spherical aberration inducedSpherical aberration induced by LASIKby LASIK
Llorente, Marcos, Barbero & Merayo, IOVS (Suppl), 2002
Indu
ced
sphe
rica
lA
berr
atio
n (?
m)
Indu
ced
sphe
rica
l A
berr
atio
n (?
m)
Comparison with visual performance
Contrast sensitivity MTF horizontal sectionPRE & POST PRE & POST
LASIKLASIK
CSFCSF
Co
ntr
ast
sen
siti
vity
0.0 4.0 8.0 12.0 16.0 20.0spatial frequency(c/deg)
0
40
80
120
Mo
du
lati
on
tra
nsf
er
MTFMTF
0 10 20 30spatial frequency (c/deg)
0.0
0.2
0.4
0.6
0.8
1.0
undilated pupil 3 mm
Area Area = 1.51= 1.51PREPREPRE
POSTPOST Area Area = 1.38= 1.38PREPREPRE
POSTPOSTMarcos. J. Refract. Surg . (2001)
ContrastContrast ratio POST/PREratio POST/PRE
0 10 20 30spatial frequency (c/deg )
0.2
0.4
0.6
0.8
1.0
CSF ratio
MTF ratio
Co
ntr
astr
atio
PR
E/P
OS
TAverage 22 eyes
Marcos. J. Refract. Surg . (2001)
Total and corneal aberrometry provide:?Detailed evaluation of correction procedures?Clues for improvent and customization
• LASIK ablation algorithms should be optimized to avoid aberration induction.
• IOL lenses design could improve to achieve better corneal/internal balance
Publicationshttp://www.io.csic.es/susana/susana.htm
17
Collaborative Clinical Sites
Instituto de Oftalmobiologia Aplicada, U. Valladolid(Jesus Merayo)
Fundacion Jimenez Diaz, Madrid(Ignacio Jimenez-Alfaro)
Carlos Dorronsoro
DanielCano
Elena Garcia de la Cera
SergioBarbero
LourdesLlorente
Funding
Grant CAM08.7/0010.1/2000Madrid Regional Government
Carl Zeiss, S.A., Spain
, Atlanta, GA
Grant BFM2002-02638Spanish Ministry of Science and Technology
Alcon Research Labs