Evolution of Diffractive MultifocalEvolution of Diffractive MultifocalIntraocular LensesIntraocular Lenses

Wavefront CongressWavefront CongressFebruary 24, 2007February 24, 2007

Michael J. Simpson, Ph.D.Michael J. Simpson, Ph.D.Alcon Research, Ltd., Fort Worth, TexasAlcon Research, Ltd., Fort Worth, Texas

Presentation OverviewPresentation Overview Multifocal Multifocal IOLsIOLs

two lens powerstwo lens powers

Early Diffractive multifocal IOLEarly Diffractive multifocal IOL full-optic, equal energyfull-optic, equal energy rigid, meniscus, strong loops (it is not just the optics)rigid, meniscus, strong loops (it is not just the optics)

Full-optic, equal energy, foldableFull-optic, equal energy, foldable Full-optic, unequal energy, foldableFull-optic, unequal energy, foldable ReSTOR Apodized diffractiveReSTOR Apodized diffractive DiscussionDiscussion

Multifocal Multifocal IOLsIOLs

Two primary lens powersTwo primary lens powersdistancenear

Base power for distance visionBase power for distance vision

““AddAdd”” power for near vision power for near vision

20 Years of Multifocal 20 Years of Multifocal IOLsIOLs (1987-2007) (1987-2007)

e.g.IOLABNuVue

e.g. StorzTrueVista

e.g.AMOArray/ReZoom

n=near d nd

ndnd

2 zones 3 zones 5 zones

d

Zonal Refractive: Each zone has either distance or near power

d=distance

12 diffractive zones.e.g. Alcon AcrySofReSTOR

Apodized Diffractive: Central diffractive blends into outer distance power

~ 30 diffractive zones.e.g. 3M 815LE,Pharmacia 811 E,AMO Tecnis 9001

Diffractive: Light goes into both distance and near powers from all zones

Diffractive Multifocal LensesDiffractive Multifocal Lenses Physical geometry is very importantPhysical geometry is very important

Place zone boundary where optical distancePlace zone boundary where optical distanceto image increases by 1 wavelengthto image increases by 1 wavelength

Create optical jump in phase at boundaryCreate optical jump in phase at boundary Zones shaped to direct lightZones shaped to direct light Light from all zones goes to both imagesLight from all zones goes to both images Adjacent zones have Adjacent zones have

similar effectssimilar effects

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Full-optic Equal-Energy Diffractive IOLFull-optic Equal-Energy Diffractive IOLTheoretical Energy Balance at 550 nmTheoretical Energy Balance at 550 nm

81% theoreticalmaximum

constant diffractive steps heights across entire lens

distance and near ~ 41 % for all pupils

additional energy goes to higher diffraction orders

steps only ~ 1-2 microns

• Rigid PMMA lenses•6mm diameter, large incision

• Meniscus optic shape• meniscus lenses no longer used

•Closed-loop and long haptics• large force on capsule

Full Optic Equal-Energy Diffractive IOLFull Optic Equal-Energy Diffractive IOLInitial 3M Diffractive IOL, 1988Initial 3M Diffractive IOL, 1988

Improvements to Improvements to IOLsIOLs and surgery : and surgery :The lens platform is also importantThe lens platform is also important

Foldable lenses have replaced rigid lensesFoldable lenses have replaced rigid lenses smaller incisions, lower aberrationssmaller incisions, lower aberrations

PhacoemulsificationPhacoemulsification and capsular bag implantation and capsular bag implantation IOLsIOLs stable in the bag stable in the bag

Gentle Gentle hapticshaptics strong strong hapticshaptics of early lenses displaced the optic of early lenses displaced the optic

Reduced PCO (Posterior Capsular Reduced PCO (Posterior Capsular OpacificationOpacification)) improved contrastimproved contrast

Aberration control (shape factor and Aberration control (shape factor and asphericityasphericity)) reduced spherical aberrationreduced spherical aberration improved large-pupil contrastimproved large-pupil contrast

• Biconvex 3M IOLs, rigid PMMA• Biconvex Pharmacia 811E, rigid PMMA• Biconvex AMO Tecnis Z9001, foldable silicone, aspheric

More recent Full Optic Equal-Energy Diffractive More recent Full Optic Equal-Energy Diffractive IOLsIOLsLenses with published clinical dataLenses with published clinical data

Full Optic Full Optic UnUnequal-Energy Diffractive equal-Energy Diffractive IOLsIOLs

Changing the step heights changes the energyChanging the step heights changes the energy lower steps send more light to distancelower steps send more light to distance higher steps send more light to nearhigher steps send more light to near all zones have the same optical effectall zones have the same optical effect

““Distance dominantDistance dominant”” or or ““Near dominantNear dominant””

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n) Equal dEqual n70/30 d70/30 n

Full Optic Full Optic UnUnequal Energy Diffractive equal Energy Diffractive IOLsIOLs

shorter steps send less light to near

taller steps send more light to near

Diffractive step heights control the energyDiffractive step heights control the energy Total energy for the two powers typically ~81%Total energy for the two powers typically ~81%

distance energy for shorter steps; near energy for taller steps

near energy for shorter steps; distance energy for taller steps

Full Optic Full Optic UnUnequal Energy Diffractive equal Energy Diffractive IOLsIOLs

Energy balance sometimes given just for primaryEnergy balance sometimes given just for primarypowerspowers portion of total energy not always givenportion of total energy not always given e.g. 70%:30% e.g. 70%:30% distance:neardistance:near energy, energy,

•• actually 57% distance, 25% near at design wavelengthactually 57% distance, 25% near at design wavelength

IOL examples are IOL examples are AdatomedAdatomed, , Acri.TwinAcri.Twin, and, andAcri.LisaAcri.Lisa IOLsIOLs foldable diffractive lensesfoldable diffractive lenses biconvexbiconvex asphericaspheric sloped diffractive steps for sloped diffractive steps for Acri.LisaAcri.Lisa

Limited published clinical dataLimited published clinical data

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Limitations of Full Optic Diffractive Limitations of Full Optic Diffractive IOLsIOLs

Near vision rarely used for large pupilactivities, and the near componentcreates a halo effect for distance visionwith large pupils

Most large pupil activitiesinvolve distance vision

The maximum energy in thetwo images is about 81%

Theoretical relative energy at design wavelength between distance and near

Apodized Diffractive Surface and Energy BalanceApodized Diffractive Surface and Energy Balance

ReSTOR use of Apodization toReSTOR use of Apodization toControl Defocused LightControl Defocused Light

The ReSTOR Apodized Diffractive OpticThe ReSTOR Apodized Diffractive Optic

Step heightsdecreaseperipherallyfrom 1.3 – 0.2microns

Central 3.6 mmapodized diffractive

structure

Outer refractive region

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Equal dEqual n70/30 d70/30 nReSTOR dReSTOR n

Energy Balance ComparisonEnergy Balance Comparison

apodized diffractive

equal energy diffractive

unequal energy diffractive

Apodized Diffractive DesignApodized Diffractive Design

Diffractive zones are in same locations as for full-Diffractive zones are in same locations as for full-optic diffractive IOLoptic diffractive IOL zone location determined by zone location determined by ““AddAdd”” power power

Apodized diffractive structure blends into peripheralApodized diffractive structure blends into peripheralrefractive regionrefractive region

Matches optical properties to visual needsMatches optical properties to visual needs Reduces nighttime visual phenomenaReduces nighttime visual phenomena Increases overall percentage of light usedIncreases overall percentage of light used

Apodized Diffractive IOL Lens PlatformApodized Diffractive IOL Lens Platform

•• Proven AcrySof materialProven AcrySof material•• Single-Piece designSingle-Piece design•• Slow, controlled, unfoldingSlow, controlled, unfolding•• Easy to insertEasy to insert

~ 25 Million AcrySof lenses implanted

Large Binocular Depth of FocusLarge Binocular Depth of Focus

n= 27

n= 34

excellent distance vision excellent near vision

n=22 ReSTOR, n=17 monofocal

80

17

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0102030405060708090

100

% o

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ject

s

Never Sometimes Always

Overall Spectacle Wear

ReSTOR (N=339)

High level of Spectacle IndependenceHigh level of Spectacle Independence

Modest Visual DisturbancesModest Visual Disturbances120-180 Days Post-Operative120-180 Days Post-Operative

Night Vision Problems

Halos Glare

ReSTOR®

N=457

MonofocalControlN=156

None, Mild Moderate Severe

9%4%

87% 76%

5%19%

4%2%

94%

2%

97%

1%7%2%

91%

21% 5%

74%

9%4%

87% 76%

5%19%

4%2%

94%

2%

97%

1%7%2%

91%

21% 5%

74%

Conclusion:Conclusion: Diffractive Multifocal Diffractive Multifocal IOLsIOLs

Diffraction divides light between two powersDiffraction divides light between two powers Diffractive step heights control the energy balanceDiffractive step heights control the energy balance Apodized diffractive IOL has gradual change inApodized diffractive IOL has gradual change in

step heightsstep heights central distance/near vision regioncentral distance/near vision region outer outer ““refractiverefractive”” distance vision region distance vision region allocates appropriate light energy according to activityallocates appropriate light energy according to activity

and light levelsand light levels designed to minimize photic issuesdesigned to minimize photic issues high level of spectacle independencehigh level of spectacle independence

Thank YouThank You