Toric lenses san diego 07

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Perfect Vision's Dr Con Moshegov presentation on: Toric lenses san diego 07

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  • In Part 1 of this presentation, we will describe the new AcrySof ® Toric IOL and discuss its principal design features, its benefits to both patients and surgeons, and the results of a clinical study. The cylinder power options to be made available initially will also be covered.
  • The AcrySof ® Toric IOL is a foldable, single-piece IOL intended for placement within the capsular bag following cataract surgery in patients with pre-existing corneal astigmatism.   It is based on the proven AcrySof ® Single-Piece Natural blue-light filtering technology. The AcrySof ® Toric IOL features a fully functional 6.0-mm optic as well as STABLEFORCE ® haptic design. The AcrySof ® Toric IOL is designed to be delivered into the capsular bag using an injector-style delivery, just as conventional monofocal IOLs are implanted.  
  • The acrylic material of which the IOL is made is soft and malleable, which allows for easy manipulation by the surgeon while positioning the IOL in the capsular bag. Additionally, the lens material is highly biocompatible, and has adhesive properties that help prevent rotation after implantation within the capsular bag. Reference: Oshika T, et al. Adhesion of lens capsule to intraocular lenses of PMMA, silicon, and acrylic foldable materials: an experimental study. Br J Ophthalmol . 1998;82:468.
  • The importance of maintaining lens stability within the capsular bag cannot be overstated. Rotation of the IOL off axis reduces the corrective cylinder power of a toric IOL.   Generally, for every 1 degree of rotation, 3.3% of the lens cylinder power is lost. Therefore, 30 degrees of rotation could cause a complete loss of astigmatic correction, and more rotation than this may induce additional astigmatism and potentially increase visual problems for the patient.
  • The process of selecting the appropriate AcrySof ® Toric IOL model for a given patient starts with determination of the required spherical lens power. Surgeons should use their preferred method and formulae as for conventional monofocal IOLs to determine spherical power requirements for a patient.   The magnitude, orientation, and type of pre-existing corneal astigmatism to be treated are best determined by manual keratometry and topography; subjective refraction data is not advised in order to avoid the influence of any lenticular astigmatism which will be eliminated when the cataractous crystalline lens is removed.
  • Once biometry and manual keratometry are completed, the spherical power and K readings are then used to determine the optimal AcrySof ® Toric IOL model by entering required data into the online AcrySof ® Toric IOL Calculator. It is important to note that the Calculator takes into consideration the effect of incision location and surgically induced cylinder to make a more precise calculation. After entering all required information, the Calculator will determine the correct IOL model and the optimal axis placement of the IOL in the capsular bag.   The AcrySof ® Toric IOL Calculator will be described and explained in greater detail later in this orientation program.
  • The chart shown here depicts for each of the three AcrySof® Toric IOL models initially available: the model number, 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.
  • Axis marking: After phacoemulsification, using the reference marks as a guide, the patient’s eye is marked accurately at two positions (180 degrees apart) that define the optimal axis of IOL placement as determined by the AcrySof ® Toric IOL Calculator.
  • Let us review the key points. The AcrySof ® Toric IOL has been designed for maximum rotational stability on the basis of the AcrySof ® Single-Piece IOL platform, STABLEFORCE ® haptic design, and AcrySof ® IOL material. The AcrySof ® Toric IOL retains all the benefits of the AcrySof ® Single-Piece IOL platform and blue-light filtering chromophore, with the added features of toricity and axis markings on the posterior surface of the IOL.
  • Toric lenses san diego 07

    1. 1. Alcon AcrySof ® Toric IOL Con Moshegov Stephen Bambery Australia
    2. 2. IOL Design <ul><li>AcrySof Single piece foldable acrylic </li></ul><ul><li>Soft and malleable </li></ul><ul><li>Allows easy manipulation while positioning </li></ul><ul><li>Axis marks on the posterior surface </li></ul><ul><li>IOL placed with marks aligned with the steep axis of the cornea </li></ul>
    3. 3. <ul><li>Blue-light filter </li></ul><ul><li>Injector delivery same as conventional SN60AT IOLs </li></ul>
    4. 4. Other toric IOLs <ul><li>Silicone plate haptic: rotation in capsular bag has been an issue </li></ul><ul><li>First toric FDA approval </li></ul>
    5. 5. AcrySof Single Piece IOL <ul><li>Adhesive property </li></ul><ul><li>Advantage taken to prevent rotation after implantation </li></ul>Oshika T, et al. Adhesion of lens capsule to intraocular lenses of PMMA, silicon, and acrylic foldable materials: an experimental study. Br. J Ophthalmol , 1998;82:468.
    6. 6. IOL Design – Rotational Stability <ul><li>Lens stability is important </li></ul><ul><li>Off-axis rotation reduces the corrective cylinder power </li></ul>
    7. 7. <ul><li>For every 1°of rotation, 3.3% of the lens cylinder power is lost </li></ul><ul><li>For 30° of rotation there is a complete loss of astigmatic correction </li></ul><ul><li>Additional astigmatism or visual problems with greater than 30° of rotation </li></ul>
    8. 8. Error Induced from Cyclotorsional Movements <ul><li>Residual PSF and Blurred Eye Chart Letters </li></ul><ul><li>Real eye: –0.15DS –1.01DC x 0˚ </li></ul>
    9. 9. IOL Power Selection Process <ul><li>Determine the required spherical lens power </li></ul>
    10. 10. Select an AcrySof ® Toric IOL Model <ul><li>The data are entered into the AcrySof ® Toric IOL Calculator to determine the optimal model </li></ul><ul><li>Calculator </li></ul><ul><ul><li>Considers effect of incision location and surgically induced cylinder to make a more precise calculation </li></ul></ul><ul><ul><li>Determines the correct IOL model and optimal axis placement of the IOL in the capsular bag </li></ul></ul>
    11. 11. AcrySof ® Toric IOL Models <ul><li>Three AcrySof ® Toric IOL models available </li></ul><ul><li>Cylinder power option is combined with SE power 16 D to 25 D in 0.5 D increments </li></ul><ul><li>Additional power options will be added in the future to address a broader range of astigmatic conditions </li></ul>
    12. 14. ASICO instruments
    13. 15. Pre-op mark
    14. 16. Marking of the Eye – Axis Marking
    15. 17. Astigmatism SEC Holladay Data Base 0.916 D Average K astig 2.4% >/= 3 D 8.6% >/= 2 D 39% >/= 1 D n = 3538
    16. 18. Surgically induced astigmatism <ul><li>Holladay IOL Consultant </li></ul><ul><li>SIA = 0.13 (SD 0.39) </li></ul><ul><li>N = 41 </li></ul><ul><li>2.75 mm (pre implantation) temporal clear corneal wound </li></ul><ul><li>OD 180 ° OS 10° </li></ul><ul><li>No other incisions </li></ul>
    17. 19. Pre op: Toric vs. LRI N=55 N=75 -0.25 -0.25 aim 100% 96% cyl >/= 1 D 32% 21% cyl >/= 2 D 1.84 D 1.75 D Pre-op cyl SN60AT with LRIs n=55 Acrysof Toric n=75
    18. 20. Post op: Toric vs. LRI -0.575 -0.45 Mean SE 0.97 D 0.48 D Post-op refractive cyl 85% 93% >/= 6/12 24% 56% >/= 6/6 SN60AT + LRIs Acrysof Toric
    19. 21. SEC experience <ul><li>25.5% of cataract patients have a toric IOL </li></ul><ul><li>Over half are T3 </li></ul>56% T3 25% T5 19% T4
    20. 22. IOL rotation <ul><li>Follow-up: about a month later </li></ul><ul><li>n = 38 </li></ul><ul><li>Av = 2.66 (0 –7.5 °) </li></ul><ul><li>92% < 5 ° </li></ul><ul><li>Direction: equal clockwise and anticlockwise </li></ul>
    21. 23. Measuring axis post-op
    22. 24. Conclusion <ul><li>AcrySof ® Toric IOL </li></ul><ul><li>We can confirm that the lens has excellent rotational stability at 1 month </li></ul><ul><li>It handles just as easily as any AcrySof single piece lens </li></ul><ul><li>More reliable than spherical lens and LRIs in improving uncorrected distance visual acuity </li></ul>

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