1. Associate Professor of Ophthalmology
Wavefront-guided Photorefractive Keratectomy to Correct Ametopia following ReSTOR Implantation
Irene C. Kuo, MD
Associate Professor of Ophthalmology
Wilmer Eye Institute
I have no financial interests; research supported by an unrestricted grant from Research to Prevent Blindness, NY, NY
ASCRS 2009, San Francisco, P-191A

2. Co-authors Elliott Myrowitz, OD Oliver Schein, MD, MPH, MBA
Roy S. Chuck, MD, PhD (consultant for Advanced Medical Optics, Inc., and Alcon Laboratories, Inc.)

3. Introduction
expectations of refractive outcomes after cataract surgery are increasing.
ametropia can still occur with multifocal lens implantation despite advanced surgical techniques and sophisticated methods to predict intraocular lens power.
Kuo , ASCRS 2009

4. Introduction
few reports of excimer laser surgery to correct residual refractive error in patients implanted with multifocal lenses
questions about accuracy of wavefront acquisition in multifocal lenses, both diffractive and refractive types
Kuo , ASCRS 2009

5. ReSTOR lens: apodized diffractive, refractive IOL
Two primary focal points--distance and near (approx 3.2 D add power in spectacle plane). 12 diffractive discontinuities (steps) in the anterior surface of the cast-molded acrylic optic provide the diffractive add power. The steps cover the central 3.6 mm diameter of the IOL. The optic from 3.6 mm to the 6.0 mm edge is comprised of a refractive surface dedicated to distance vision. ≤2 mm pupil, 41% distance, 41% near, 18% to higher diffractive orders (with permission from Davison JA, Simpson MJ. History and development of the apodized diffractive intraocular lens. J Cataract Refract Surg 2006;32: ).

6. Methods IRB-approved protocol for refractive patients
thorough preoperative evaluation
detailed medical, ocular, social history
uncorrected and best corrected visual acuity
manifest refraction , cycloplegic refraction
corneal topography, pachymetry
slit-lamp examination, pupillary exam, Schirmer testing, dilated exam
Kuo, ASCRS 2009

7. Methods Orbscan (Bausch and Lomb)
CustomVue Wavescan (Advanced Medical Optics)
three or more measurements are obtained with undilated pupil; 5 mm pupil or larger needed for wavescan capture
measurement where wavefront sphere best matches manifest sphere is chosen for treatment
physician adjustments to sphere are performed where needed to improve match between manifest and wavefront sphere
Kuo, ASCRS 2009

8. Methods VISX STAR S4 (Advanced Medical Optics) was used in all cases
eye tracker and iris registration were engaged in all eyes
off-label use of VISX laser in setting of pseudophakia was discussed with each patient
Kuo, ASCRS 2009

9. Case YAG laser capsulotomy in June 2007
78-year-old man with bilateral cataracts
Preoperative Ks x D in OS at 169 degrees by IOL Master
November 2006: uncomplicated cataract extraction OS, with 19.5 D ReSTOR SN6AD3 (+4 diopter add in IOL plane) and limbal relaxing incisions
YAG laser capsulotomy in June 2007
August 2007: UCVA was 20/40 and BCVA was 20/30 with manifest refraction of x 175—wavefront PRK
Kuo, ASCRS 2009

10. Case
corneal pachymetry was 580 microns. Keratometry was x D at 175 by Orbscan
CustomVue Wavescan showed an RMS of 0.43 µm
patient underwent wavefront-guided PRK in OS with goal of postoperative emmetropia
wavefront data from a 5.25 mm pupil was used. Physician adjustment of diopters was incorporated in treatment
Kuo, ASCRS 2009

11. Kuo, ASCRS 2009

12. Kuo, ASCRS 2009

13. Results
Post-CE-IOL and pre-PRK
Post-PRK
UCVA
MR, BCVA
near
1-2 months
3-6 months
7-10 months months
MR, BCVA, Near
Case 1 OS
20/50
plano+1.25x020
20/20 J6
20/25
x145,
-0.25, 20/25, J3
Plano, 20/20, J1+
Case 2 OD
20/40
x175
20/30
x035, J4 J5
x040,
x100
x110
20/30 J2+
Plano, 20/25, J / J2
x090
20/25, J2
Visual acuity of eyes with ReSTOR lens before and after PRK. CE-IOL=cataract extraction with ReSTOR implantation, UCVA=uncorrected Snellen visual acuity, BCVA=best-corrected Snellen visual acuity, MR=manifest refraction, J=Jaeger. All manifest refractions are in diopters.
Kuo, ASCRS 2009

14. Hartmann-Shack Aberrometer
CCD-Camera
Lens Array
Outcoming Wave
CCD-Image
With permission from AMO, Inc.

15. Hartmann-Shack Aberrometer
Each Spot or lenslet
lets in light
Each spot is analyzed
as to how the light is traveling in that part
of the eye
WaveScan® software calculates the wavefront map and generates a wavefront treatment for the laser to follow
240 points in a 7 mm pupil
With permission from AMO, Inc.

16. Why wavefront-guided treatment?
seems appropriate to correct refractive error after implantation of an aspheric multifocal lens
offers iris registration
compensates for cyclotorsion and pupil centroid shift, thus correcting astigmatism more precisely than conventional treatment
Kuo, ASCRS 2009

17. Role of excimer laser after multifocal lens implantation
unavailability of toric multifocal lenses
“refractive surprises”
range of lens powers for the ReSTOR lenses is smaller than range for monofocal lenses
any residual refractive error after multifocal lens implantation will affect vision (and contrast sensitivity) at all distances
Kuo, ASCRS 2009

18. Drawbacks of H-S sensor with multifocal IOL
diffractive discontinuities in lens may result in locally distorted wavefronts
spatial distribution of stray centroids (just inside or outside pixel subarray of charge-coupled device) may be hard to predict
scattering incurred by discrete junctions between diffractive zones
may lead to overestimation of the optical quality of eyes with diffractive multifocal IOLS
Kuo, ASCRS 2009

19. Drawbacks of H-S sensor with multifocal IOL
concentric zones in ReSTOR vs. square microlens array may lead to inaccurate reconstruction of wavefront
Kuo, ASCRS 2009

20. Drawbacks of H-S sensor
Perhaps the findings from our three cases will not be true with larger refractive errors and/or with lens tilt/decentration
tilt/decentration may be more deleterious in aspheric than in spheric lenses
size of capsulorhexis and clarity of posterior capsule may also interfere with good wavefront capture
Kuo, ASCRS 2009

21. Why H-S data may still be acceptable
At the wavelength used, the aberrometer may be unaffected by the diffractive effect of the ReSTOR lens
the higher the wavelength used in the wavefront sensor, the lower the diffractive efficiency, and the higher the add power
Kuo, ASCRS 2009

22. Why H-S data may still be acceptable
the H-S aberrometers seem more likely to produce wavefront results corresponding to the wavefront produced by the distance power of a diffractive IOL
Hence, the relative lack of “doubling” of spots in H-S images in eyes with the ReSTOR
Kuo, ASCRS 2009

23. Conclusions
It is possible to obtain good quality wavefront data in patients with ReSTOR lens and to use such data to design wavefront-guided treatment to maximize uncorrected distance and near visual acuities after ReSTOR
reproducible, well-focused, properly aligned image
wavefront and manifest refractions correlate
Ortiz et al confirmed using another H-S system
Kuo, ASCRS 2009

24. Conclusions
It is possible to “mix and match” platforms—one company’s IOL and another company’s wavefont-guided laser
Kuo, ASCRS 2009 24

25. Conclusions
in our cases, PRK was chosen over laser in-situ keratomileusis (LASIK) because of low refractive error and possibility that LASIK flap might induce more aberrations
However, perhaps not all patients with multifocal IOLs will qualify for wavefront-guided excimer laser treatment
type of IOL, amount of refractive error , corneal topography, pachymetry

26. Conclusions
The three eyes in our series had good quality wavescans which were used for wavefront-guided PRK, with subsequent improvement of UCVA and in one case, BCVA
delay in achieving best UCVA and BCVA
results of (older) patients undergoing conventional laser surgery to correct post-cataract surgery ametropia vs. patients who have not had CE-IOL

27. References
Charman WN, Montés-Micó R, Radhakrishnan H. Problems in the measurement of wavefront aberration for eyes implanted with diffractive bifocal and multifocal intraocular lenses. J Refract Surg. 2008; 24(3):
Davison JA, Simpson MJ. History and development of the apodized diffractive intraocular lens. J Cataract Refract Surg 2006;32:
Gatinel D. Limited accuracy of Hartmann-Shack wavefront sensing in eyes with diffractive multifocal IOLs [letter]. J Cataract Refract Surg 2008;34:528
Jendritza BB, Knorz MC, Morton S. Wavefront-guided excimer laser vision correction after multifocal IOL implantation. J Refract Surg 2008;24:

28. References
Ortiz D, Alio J, Bernabeu G, Pongo V. Optical performance of monofocal and multifocal intraocular lenses in the human eye. J Cataract Refract Surg 2008;34:
Altmann GE, Wavefront-customized intraocular lenses. Curr Opin Ophthalmol 2004;15:
Holladay JT, Piers PA, Koranyi G, van der Mooren M, Norrby NE. A new intraocular lens design to reduce spherical aberration of pseudophakic eyes. J Refract Surg 2002;18:
Atchison DA. Design of aspheric intraocular lenses. Ophthalmol Physiol Opt 1991;11:
Altmann GE, Nichamin LD, Lane SS, Pepose JS. Optical performance of 3 intraocular lens designs in the presence of decentration. J Cataract Refract Surg 2005;31: 28