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Cataract and Refractive Surgery.ppt
- 1. Eastwood Eye Surgery Toric andModern IOL Technology Dr Gagan Khannah Ophthalmic Surgeon Eastwood Eye Surgery Sydney Eye Hospital Stamford Grand 3rd May 2009
- 2. Eastwood Eye Surgery Cataract andRefractive Surgery Cataract surgery and refractive surgery are now seen as a surgical spectrum Significant advances in safety, technology, techniques and results 2006 200,000 Cataract operations 2006 50,000 Refractive operations >10% of >60yo have IOLs Cataract surgery is very cost effective surgery
- 3. Eastwood Eye Surgery Two ResidualProblems Routine monofocal IOL cataract surgery results does not overcome: – Presbyopia – Astigmatism
- 4. Eastwood Eye Surgery Treatment ofAstigmatism Spectacles or Contact lenses Excimer Laser: LASIK or PRK Incisional Corneal Surgery: LRI or AK Toric IOLs – Correct corneal astigmatism
- 5. Eastwood Eye Surgery Toric IOLs TheStaar plate haptic AA4203 IOL became the first FDA approved toric IOL in November 1998 – Poor rotational stability (>20%)
- 6. Eastwood Eye Surgery Toric IOLs RaynerT-flex® Toric Zeiss Acri.Comfort 646 TLC Alcon AcrySof® Toric IOL
- 7. IOL Design Single pieceand foldable Acrylic Placed within the capsular bag For pre-existing corneal astigmatism Blue-light filtering technology 6.0-mm optic Injector-style delivery similar to conventional monofocal IOLs Adhesive property Prevents rotation after implantation NOT Aspheric
- 8. Eastwood Eye Surgery IOL Design– Optic Markings Surgeons must Choose the correct AcrySof® Toric IOL power Ensure precise alignment of IOL within the eye relative to the patient’s axis of corneal astigmatism Designed with axis marks on the posterior surface IOL placed and marks aligned precisely with the steep axis of the postincisional cornea
- 9. Eastwood Eye Surgery IOL Design– Rotational Stability Lens stability is important Off-axis rotation reduces the corrective cylinder power For every 1° of rotation, 3.3% of the lens cylinder power is lost For 30° of rotation there is a complete loss of astigmatic correction Additional astigmatism or visual problems with greater than 30° of rotation
- 10. Eastwood Eye Surgery IOL Design– Rotational Stability STABLEFORCE® haptic design and adhesive nature of AcrySof® Toric IOL material provide high level of rotational stability Average rotation of less than 4° at six months post-op STABLEFORCE® haptic design allows the IOL to conform to the capsular bag Promotes optimal placement and centration in different sized capsular bags
- 11. Eastwood Eye Surgery AcrySof® ToricIOL 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
- 12. Eastwood Eye Surgery Patient SelectionCriteria Proper patient selection is critical to achieve success Suitable candidates are cataract patients with pre-existing corneal astigmatism > 0.75 D with the following characteristics – Manual keratometry: steep and flat meridians ~90° apart – Corneal topography: symmetrical astigmatism – Intact capsular bag compatible with continuous curvilinear capsulotomy performed with in-the-bag placement of the IOL
- 13. Eastwood Eye Surgery IOL PowerSelection 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
- 14. Eastwood Eye Surgery Selecting anAcrySof® Toric IOL Model The data are entered into the AcrySof® Toric IOL Calculator to determine the optimal model Calculator – Considers the effect of incision location and surgically induced cylinder to make a more precise calculation – Determines the correct IOL model and optimal axis placement of the IOL in the capsular bag
- 15. Eastwood Eye Surgery AcrySof® ToricIOL Calculator Manual keratometry is recommended Output data are displayed in a format suitable for printing for – Reference in the operating room – Inclusion in the patient’s chart Determines the optimal axis placement of the lens within the capsular bag Compensates for expected surgically induced astigmatism Allows for customization of important variables to accommodate individual surgeon preferences
- 16. Eastwood Eye Surgery Estimated Surgically-inducedCylinder Directly impacts the amount and/or axis of post-incisional astigmatism to be corrected Surgeons should enter a number that represents their actual historical average of surgically- induced cylinder and then customize it Based on clinical data, a default value of 0.5 D is provided as a starting point
- 17. Eastwood Eye Surgery Marking ofthe Eye Two steps – Reference Marking – Axis Marking Reference Marking – Pre-induction period – Patient in upright position – Two reference marks placed at the limbus, 180 degrees apart – Used later to align the marking instrument for placement of axis marks Axis Markings • Define the optimal axis of IOL placement • Determined by the AcrySof® Toric IOL Calculator • Using the reference marks as a guide, the patient’s eye is marked accurately at two positions, 180 degrees apart
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- 20. Eastwood Eye Surgery Intraoperative IOLAlignment Gross alignment – Inject the IOL into the capsular bag – Rotate the IOL clockwise, approximately 20° to 30° short of the intended final axis location Viscoelastic removal – Ensure that the IOL does not rotate beyond the intended final axis location – Carefully remove viscoelastic from both the anterior and posterior sides of the lens Final alignment of the IOL – Rotate the lens clockwise precisely to the intended axis of alignment as previously marked
- 21. Eastwood Eye Surgery Summary AcrySof® ToricIOL – Good rotational stability – The presence of an online calculator brings a high level of precision and accuracy to the selection of the correct IOL model and optimal axis placement of the IOL. Provides flexibility in surgical planning for precise correction of astigmatism – Routine surgical technique except accurate marking of the eye, and precise alignment of the IOL within the capsular bag
- 22. Eastwood Eye Surgery Limitations Not Aspheric Limitedcylinder power options No combination of Toric Multifocal yet Always under promise and over deliver!!
- 23. Eastwood Eye Surgery Future: SuperIOL One piece Acrylic Aspheric Accommodative or Multifocal Toric Preloaded Centration will become vital
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