EastwoodEye Surgery

Toric and Modern IOL Technology

Dr Gagan KhannahOphthalmic Surgeon

Eastwood Eye SurgerySydney Eye Hospital

Stamford Grand3rd May 2009

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Cataract and Refractive Cataract and Refractive SurgerySurgery

Cataract surgery and refractive surgery Cataract surgery and refractive surgery are now seen as a surgical spectrumare now seen as a surgical spectrumSignificant advances in safety, technology, Significant advances in safety, technology, techniques and results techniques and results 2006 200,000 Cataract operations 2006 200,000 Cataract operations 2006 50,000 Refractive operations2006 50,000 Refractive operations>10% of >60yo have IOLs>10% of >60yo have IOLsCataract surgery is very cost effective Cataract surgery is very cost effective surgerysurgery

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Two Residual ProblemsTwo Residual Problems

Routine monofocal IOL cataract surgery Routine monofocal IOL cataract surgery results does not overcome:results does not overcome:

– PresbyopiaPresbyopia

– AstigmatismAstigmatism

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Treatment of AstigmatismTreatment of Astigmatism

Spectacles or Contact lensesSpectacles or Contact lenses

Excimer Laser: LASIK or PRKExcimer Laser: LASIK or PRK

Incisional Corneal Surgery: LRI or AKIncisional Corneal Surgery: LRI or AK

Toric IOLsToric IOLs– Correct Correct cornealcorneal astigmatism astigmatism

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Toric IOLsToric IOLs

The Staar plate haptic AA4203 IOL The Staar plate haptic AA4203 IOL became the first FDA approved toric IOL in became the first FDA approved toric IOL in November 1998 November 1998

– Poor rotational stability (>20%)Poor rotational stability (>20%)

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Toric IOLsToric IOLs

Rayner T-Rayner T-flexflex®® Toric Toric

Zeiss Acri.Comfort 646 TLCZeiss Acri.Comfort 646 TLC

Alcon Alcon AcrySof® Toric IOL

IOL DesignIOL Design

Single piece and foldable AcrylicSingle piece and foldable AcrylicPlaced within the capsular bag Placed within the capsular bag For pre-existing corneal For pre-existing corneal astigmatismastigmatismBlue-light filtering technologyBlue-light filtering technology6.0-mm optic6.0-mm opticInjector-style delivery similar to Injector-style delivery similar to conventional monofocal IOLsconventional monofocal IOLsAdhesive property Adhesive property Prevents rotation after Prevents rotation after implantationimplantationNOT AsphericNOT Aspheric

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IOL Design – Optic MarkingsIOL Design – Optic Markings

Surgeons must Surgeons must

Choose the correct Choose the correct AcrySofAcrySof®® Toric IOL power Toric IOL power

Ensure precise alignment of Ensure precise alignment of IOL within the eye relative IOL within the eye relative to the patient’s axis of to the patient’s axis of corneal astigmatismcorneal astigmatism

Designed with axis marks Designed with axis marks on the posterior surfaceon the posterior surface

IOL placed and marks IOL placed and marks aligned precisely with the aligned precisely with the steep axis of the steep axis of the postincisional corneapostincisional cornea

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IOL Design – Rotational StabilityIOL Design – Rotational Stability

Lens stability is importantLens stability is important

Off-axis rotation reduces Off-axis rotation reduces the corrective cylinder the corrective cylinder power power

For every 1° of rotation, For every 1° of rotation, 3.3% of the lens cylinder 3.3% of the lens cylinder power is lostpower is lost

For 30° of rotation there is a For 30° of rotation there is a complete loss of astigmatic complete loss of astigmatic correctioncorrection

Additional astigmatism or Additional astigmatism or visual problems with greater visual problems with greater than 30° of rotation than 30° of rotation

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IOL Design – Rotational StabilityIOL Design – Rotational Stability

STABLEFORCESTABLEFORCE®® haptic haptic design and adhesive nature design and adhesive nature of AcrySofof AcrySof®® Toric IOL Toric IOL material provide high level of material provide high level of rotational stability rotational stability Average rotation of less than Average rotation of less than 4° at six months post-op4° at six months post-opSTABLEFORCESTABLEFORCE®® haptic haptic design allows the IOL to design allows the IOL to conform to the capsular bagconform to the capsular bagPromotes optimal placement Promotes optimal placement and centration in different and centration in different sized capsular bagssized capsular bags

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AcrySofAcrySof®® Toric IOL Models Toric IOL Models

• Three AcrySof® Toric IOL models initially available

• Chart shows the model numbers, the power at the IOL and corneal planes, and the recommended range of astigmatism correction

• Additional power options will be added in the future to address a broader range of astigmatic conditions

• Aspheric models to be released in Australia

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Patient Selection CriteriaPatient Selection Criteria

Proper patient selection is critical to Proper patient selection is critical to achieve successachieve successSuitable candidates are cataract Suitable candidates are cataract patients with pre-existing corneal patients with pre-existing corneal astigmatism astigmatism > 0.75 D with the following > 0.75 D with the following characteristicscharacteristics– Manual keratometry: steep and Manual keratometry: steep and

flat meridians ~90° apartflat meridians ~90° apart– Corneal topography: symmetrical Corneal topography: symmetrical

astigmatism astigmatism – Intact capsular bag compatible with Intact capsular bag compatible with

continuous curvilinear capsulotomy continuous curvilinear capsulotomy performed with in-the-bag performed with in-the-bag placement of the IOLplacement of the IOL

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IOL Power Selection ProcessIOL Power Selection Process

• Determine the required spherical lens power

• Use manual keratometry and topography for magnitude, orientation, and type of pre-existing corneal astigmatism

• Subjective refraction data is not advised in order to avoid the influence of any lenticular astigmatism, which will be eliminated when the cataractous lens is removed

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Selecting an AcrySofSelecting an AcrySof®® Toric IOL Model Toric IOL Model

The data are entered into the The data are entered into the AcrySofAcrySof®® Toric IOL Calculator Toric IOL Calculator to determine the optimal modelto determine the optimal model

Calculator Calculator – Considers the effect of Considers the effect of

incision location and incision location and surgically induced cylinder surgically induced cylinder to make a more precise to make a more precise calculationcalculation

– Determines the correct IOL Determines the correct IOL model and optimal axis model and optimal axis placement of the IOL in the placement of the IOL in the capsular bagcapsular bag

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AcrySofAcrySof®® Toric IOL Calculator Toric IOL Calculator

Manual keratometry is Manual keratometry is recommended recommended Output data are displayed in a Output data are displayed in a format suitable for printing for format suitable for printing for – Reference in the operating Reference in the operating

roomroom– Inclusion in the patient’s chart Inclusion in the patient’s chart

Determines the optimal axis Determines the optimal axis placement of the lens within the placement of the lens within the capsular bagcapsular bagCompensates for expected Compensates for expected surgically induced astigmatismsurgically induced astigmatismAllows for customization of Allows for customization of important variables to important variables to accommodate individual accommodate individual surgeon preferencessurgeon preferences

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Estimated Surgically-induced CylinderEstimated Surgically-induced Cylinder

Directly impacts the Directly impacts the amount and/or axis of amount and/or axis of post-incisional post-incisional astigmatism to be astigmatism to be correctedcorrectedSurgeons should enter a Surgeons should enter a number that represents number that represents their actual historical their actual historical average of surgically-average of surgically-induced cylinder and then induced cylinder and then customize itcustomize itBased on clinical data, a Based on clinical data, a default value of 0.5 D is default value of 0.5 D is provided as a starting provided as a starting pointpoint

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Marking of the EyeMarking of the Eye

Two stepsTwo steps– Reference MarkingReference Marking– Axis MarkingAxis Marking

Reference MarkingReference Marking– Pre-induction periodPre-induction period– Patient in upright positionPatient in upright position– Two reference marks placed at the Two reference marks placed at the

limbus, 180 degrees apart limbus, 180 degrees apart – Used later to align the marking Used later to align the marking

instrument for placement of axis instrument for placement of axis marksmarks

Axis MarkingsAxis Markings• Define the optimal axis of IOL Define the optimal axis of IOL

placementplacement• Determined by the AcrySofDetermined by the AcrySof®® Toric Toric

IOL CalculatorIOL Calculator• Using the reference marks as a Using the reference marks as a

guide, the patient’s eye is marked guide, the patient’s eye is marked accurately at two positions, 180 accurately at two positions, 180 degrees apartdegrees apart

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Reference MarkingReference Marking

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Axis MarkingAxis Marking

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Intraoperative IOL AlignmentIntraoperative IOL Alignment

Gross alignment Gross alignment – Inject the IOL into the capsular bagInject the IOL into the capsular bag– Rotate the IOL clockwise, approximately 20° to 30° Rotate the IOL clockwise, approximately 20° to 30°

short of the intended final axis locationshort of the intended final axis location

Viscoelastic removalViscoelastic removal– Ensure that the IOL does not rotate beyond the Ensure that the IOL does not rotate beyond the

intended final axis locationintended final axis location– Carefully remove viscoelastic from both the anterior Carefully remove viscoelastic from both the anterior

and posterior sides of the lensand posterior sides of the lens

Final alignment of the IOLFinal alignment of the IOL– Rotate the lens clockwise precisely to the intended Rotate the lens clockwise precisely to the intended

axis of alignment as previously markedaxis of alignment as previously marked

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SummarySummary

AcrySofAcrySof®® Toric IOL Toric IOL– Good rotational stabilityGood rotational stability– The presence of an online calculator brings a high The presence of an online calculator brings a high

level of precision and accuracy to the selection of level of precision and accuracy to the selection of the correct IOL model and optimal axis placement the correct IOL model and optimal axis placement of the IOL. Provides flexibility in surgical planning of the IOL. Provides flexibility in surgical planning for precise correction of astigmatism for precise correction of astigmatism

– Routine surgical technique except accurate marking Routine surgical technique except accurate marking of the eye, and precise alignment of the IOL within of the eye, and precise alignment of the IOL within the capsular bagthe capsular bag

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LimitationsLimitations

Not AsphericNot Aspheric

Limited cylinder power optionsLimited cylinder power options

No combination of Toric Multifocal yetNo combination of Toric Multifocal yet

Always under promise and over Always under promise and over deliver!!deliver!!

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Future: Super IOLFuture: Super IOL

One pieceOne piece

AcrylicAcrylic

AsphericAspheric

Accommodative or MultifocalAccommodative or Multifocal

Toric Toric

PreloadedPreloaded

Centration will become vitalCentration will become vital

Thank You!Thank You!