Akreos IOL Material Fact Sheet - PDF by jki47277

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									Akreos® IOL Material Fact Sheet




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The Akreos IOL design route
There have been 5 generations of design: Akreos Disc, Akreos Fit, Akreos Adapt, Akreos AO
and the new Akreos MI-60 (Figure 1).


         July 98             May 99        May 2000          May 2005        September 2006
       Akreos Disc          Akreos Fit   Akreos Adapt        Akreos AO        Akreos MI-60




Figure 1: Akreos IOL designs

Material
The Akreos MI-60 lens, like its Akreos predecessors, is composed of a biocompatible,
hydrophilic acrylic material.

The material was developed in 1996–1997. It is a copolymer of HEMA
(hydroxyethylmethacrylate) and PMMA (polymethylmethacrylate) (Figure 2). These polymers
have a long record of use in ophthalmology, demonstrating excellent biocompatibility. PMMA
has been used in IOLs since the 1960s. HEMA is used both extraocularly in contact lenses and
intraocularly for scleral implants.

This copolymer has 26% water content which makes it compressible and foldable.




Figure 2: Chemical stucture of the Akreos lens material




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Benefits of using the Akreos IOL acrylic material for a MICS™ lens
Only a lens composed of hydrophilic acrylic material is appropriate for use in MICS, owing to its
unique properties.

•   Suitability as MICS lens – Extremely deformable, tear-resistant and easy to fold,
    independent of temperature, making it appropriate for use in sub 2 mm incisions.

       •   The hydrophilic component, HEMA, allows the lens to be easily compressed to fit
           through the microincision and unfold smoothly once implanted in the eye.

       •   The mechanical resistance of the hydrophobic acrylic component (MMA) ensures
           the lens recovers its initial shape without damage.

•   Biocompatible – A proven clinical safety record since it first implantation in 1998, now used
    in over 1.5 million implantations. Acrylic hydrophilic lenses have been shown to cause less
    inflammation than hydrophobic lenses, fewer deposits and a lower biocontamination risk1,2,3.

•   High quality optics – The lens material enables lens designs to be formed to fit with MICS
    phaco surgery, as it can be machined with high precision milling and lathe-cut machines for
    very precise optical surfaces.

       •   Homogeneous material – the water is stable inside the polymer matrix, so the
           Akreos lens material is an extremely homogeneous material with transparency
           across the optic.

       •   Moderate refractive index is 1.46, ideal to avoid flat anterior optic surfaces, which
           are the cause of many dysphotopsic effects.

Lens design

•   Akreos MI-60 lens is 30% thinner than its parent design to allow the implantation through
    a sub 2 mm incision.

•   Novel haptic design. The haptic design is slender, but ensures excellent stability of the
    implant. The external portions of the haptics, known as the absorption zone, undergo
    deformation in 3 dimensions in order to limit any pressure which may be exerted on the
    optic. The base of the haptics is rigid and thicker, and together with the optic, forms the
    foundation zone (Figures 3–5).




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Figure 3: Akreos MI-60 lens design             Figure 4: Absorption zone of haptics on Akreos
                                               MI-60 lens




Figure 5: 3-dimensional deformation of haptics on Akreos MI-60 lens

•   Anti-PCO. The Akreos MI-60 lens uses the same anti-PCO properties as the Akreos AO
    Adapt: the 360° anti-PCO barrier and square edge design (Figure 6). The haptics on the
    new lens are also angled at 10° to improve contact with the posterior capsule (Figure 7).


                                         Anti-PCO
                                          barrier




Figure 6: 360° anti-PCO barrier on Akreos MI-60 lens




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Figure 7: 10° angulation of haptics on Akreos MI-60 lens

•   Aspheric aberration-free optic. Like its predecessor, the lens uses an aberration-free
    optic. This leaves the eye with its natural degree of corneal positive spherical aberrations,
    improving contrast sensitivity and benefiting patients with a good depth of field. These
    properties were demonstrated by a Swedish multi-centre study on the Akreos Adapt AO4.




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References
1. Manuchehri K, Mohamed S, Cheung D, Saeed T, Murray PI. Brown deposits in the optic
   of foldable intraocular lenses in patients with uveitis. Eye. 2004 Jan;18(1):54–8.

2. Ursell P. Prospective randomized trial of the surface cytology of three different single-piece
   acrylic intraocular lenses. ESCRS 2003.

3. Schauersberger J, Amon M, Aichinger D, Georgopoulos A. Bacterial adhesion to rigid and
   foldable posterior chamber intraocular lenses: in vitro study. J Cataract Refract Surg. 2003
   Feb;29(2):361–6.

4. B. Johansson et al. Swedish multi-centre study to compare the optical performance of the
   Akreos Adapt Advanced Optic (AO) IOL and the Tecnis Z9000. ASCRS 2006.

™/® denotes trademark of Bausch & Lomb Incorporated or its affiliates.




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