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Types of iol
Types of intraocular lenses include foldable acrylic and silicone lenses. IOLs are either single piece or multipiece, and have different optic designs like aspheric, toric, or multifocal to correct vision. IOLs are implanted either in the capsular bag or ciliary sulcus, and are made of materials like acrylic, silicone, or hydrogels. Newer accommodating IOL designs aim to restore accommodation.
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Types of iol
- 1. Types of IOL DrRohit Rao
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- 3. Primary vs secondaryimplantation • Primary implantation – use of IOLs during surgery for cataract • Secondary implantation – implantation of IOL to correct aphakia in a previosly operated eye
- 4. Parts of anIOL • OPTIC Part of the lens that focuses light on the retina. • HAPTIC Small filaments connected to the optic that hold the lens in place in the eye HAPTEN OPTIC
- 5. MATERIALS USED FORINTRAOCULAR LENSES Optic materials 1.Non-foldable-rigid IOL • Polymethyl methacrylate(PMMA) 2.Foldable IOL • Silicone • Hydrophobic acrylic • Hydrophilic acrylic 3.Rollable/Ultra-thin IOL • Hydrogel Haptic materials • PMMA, • Polyvinylidene fluoride (PVDF), • Polyimide (elastimide), • Polypropylene (prolene)
- 6. Polymethylmethacrylate • Hard andrigid - Inert and non autoclavable. • Hydrophobic – so causes adherence of cell and bacteria • Refractive Index 1.47 and1.55
- 7. Flexible Acrylic • Hydrophilic –Unfolds in controlled fashion – Good uveal and excellent capsular biocompatibility • Hydrophobic – More prone to develop PCO • Copolymer of phenyl ethylacrylate and phenylethylmethacrylate. • Good viscoelastic and three dimensional stability • Viscoelasticity is temperature dependant with increase elasticity at higher temperature
- 8. Silicone • Elastomer Polydimethylsiloxane •Capable of large and reversible deformations • Good memory • Surface deposits are common • Additives in silicone IOL are – UV chromophore – Phenyl group to increase Refractive Index from 1.41 to 1.46
- 9. Hydrogels • HEMA or2 Hydroxyethylmethacrylate • Polymerization in ethylene glycol medium • Hydrate to form soft, swollen, rubbery mass • Hydrophilic hence repel cells and microbes • Refractive Index - 1.43 to 1.48
- 10. Truedge • Truedge 360°Square Edge acts as a mechanical barrier for cell proliferation • 10° Angulation, steep vault of 0.4 mm
- 11. Aurofold lens • negativeaspheric hydrophilic acrylic foldable intraocular lens made of p-HEMA material • Truedge technology to prevent PCO • Zero Degree Angulation
- 12. Aurofold lens • p-HEMAmaterial • Zero degree angulation • Disposable delivery system
- 13. Auro toric • AuroflexToric IOL has been carefully designed with toricity on the anterior surface of the IOL. • UV absorbing p-HEMA • OptiCal an web based online service www.aurolab.com/OptiCal.
- 14. Aurovue • Single piecehydrophobic foldable acrylic IOL • 3° Angulation • disposable delivery system
- 15. Aurovue • Aspheric optic(negative spherical aberration), preloaded hydrophobic acrylic IOL. • 3° Angulation
- 16. Acrysoft IQ • HydrophobicAcrylic IOLs • Aspheric
- 17. Sensar • Single piecehydrophobic foldable acrylic IOL • OptiEdge® with 360° square edge, and round anterior edge • 5˚ angulation
- 18. Tecnis • Biconvex, anterioraspheric surface, square optic edge • ProTEC frosted, continuous 360° posterior square edge • UV-blocking hydrophobic acrylic • Haptics offset from optic
- 19. • enVista hydrophobicacrylic IOL • No glistenings • Aberration-free aspheric Advanced Optics • Step-vaulted haptics • 360° square barrier edge enVista
- 20. Restor • Single piecefoldable acrylic IOL • Apodized Diffractive Technology • Apodization is the gradual shortening of step heights toward the periphery of the diffractive zone.
- 21. Intraocular Lens Design •multipiece or monobloc; • plate or open-loop style; • angulated or planar haptics; • special haptics for certain indications such as sulcus, anterior chamber angle, or iris fixation; • optic shape and edge design; • Optic geometry for certain indications such as toric, aspheric, or multifocal IOLs
- 23. Open-Loop • Multipiece – IOLsare held in place by exerting centripetal pressure on capsule bag fornix and or ciliary sulcus. • Single-Piece – IOLs are produced in a single step from one material – More resistant to damage with injectors – Production process is cheaper – May have less of a PCO-inhibiting effect
- 25. Haptic Angulation • Maximizethe barrier effect to migrating LECs by pushing the IOL backwards.
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- 27. POSITIONING OF IOL 1.Posterior chamber implantation • Ciliary sulcus fixation • In the bag fixation • Scleral fixation Eg:- modified C loop type IOL
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- 29. Intraocular Lenses for InsufficientCapsule Support • In cases of PCR where IOL placement is no longer possible, but ALC is intact, the IOL can be placed in sulcus. (optic capture if possible) • 0.5 diopters should be deducted • no capsule support is given, – angle-supported ACIOL, – Iris-supported IOLs – Scleral-sutured IOLs
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- 31. 2. Anterior chamber implantation •angle supported IOLs • Kelman multiflex type IOL
- 32. 3. Iris- fixatedlens • Fixed on the iris with claws,loops or sutures • Eg- Singh and Worst’s iris claw lens
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- 34. Edge Design • Sharp-edgeIOL designs – edge-glare phenomena • IOLs with a round anterior and sharp posterior optic edge seems to avoid this disturbing side effect
- 36. Optic Geometry • Biconvexity –Radius of curvature of the front and back surface are identical. • Asymmetric biconvex optic – Back surface curvature is relatively flat and constant throughout most of the power range and anterior curvature is varied for IOL power.
- 37. Aspherical Intraocular Lenses •IOL has prolate surface inducing negative SA, which should neutralize positive SA of the average cornea. • The aim is to increase contrast sensitivity under mesopic conditions where the pupil is dilated. • little to no effect when the pupil is small.
- 41. Toric Intraocular Lenses •Correcting preexisiting corneal astigmatism using incisional techniques, – Corneal incision on the steep axis, – Making limbal relaxing incisions (LRIs) on the steep axis. – Neutralizing corneal astigmatism is the use of toric IOLs • Accurate axis placement of the toric IOL is critical • 3% of toric correction is lost for every degree off axis. • Being 10 degrees off axis results in about 1/3 of toric correction lost. • Being 30 degrees off results in no toric correction
- 43. Multifocal Intraocular Lenses •Multifocal IOLs (mIOL) are designed to overcome the postoperative lack of accommodation by dividing the incoming light onto two or more focal points. • Two types of mIOLs: – Diffractive – Refractive
- 52. 3.Accomodative IOLs • Specialdesign and mechanical properties of this IOL enable lens to change power by a forward and backward movement of the optic during the contraction of ciliary muscle.
- 53. • Diameter ofthis lens optic is 5.5 mm with an overall diameter of 9.8 mm. • Four haptics which are connected to the optic with a pliable joint. • Single piece acrylic material. • Hinge type haptics permit movement between haptics and optic. • Merits – May eliminate the need of any kind of refractive correction. – There is no incidence of glare, haloes, ghost images and loss of contrast sensitivity. • Demerits – High incidence of contraction of capsular bag. – Loss of pliability of material at the haptic- optic junction.
- 58. TECNIS® symfony IOL •Proprietary diffractive echelette design feature introduces a novel pattern of light diffraction that elongates the focus of the eye resulting in an extended range of vision. • TECNIS® symfony IOL merges two complementary enabling technologies – The proprietary diffractive echelette design feature extends the range of vision. – The proprietary achromatic technology corrects chromatic aberration for enhanced contrast sensitivity.
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