NEWER IOLs•Ajay Kumar Singh•Nibha Mishra•Department of Ophthalmology•King George‘s Medical University, Lucknow(INDIA)
An artificial lens that is implanted inside the eyeusually replacing natural crystalline lens duringcataract or refractive surgery to correct opticalpower of the eye.WHAT IS AN IOL ???
HISTORYItalian scientist Tadini in mid 18th century first consideredintraocular lens implantation.In 1795, Casamata implanted glass IOL which sankposteriorly.English ophthalmologist Sir Nicholas Harold Lloyd Ridleyis credited for first successful IOL implantation on November29th 1949, at St. Thomas’ hospital in London.Sir Harold Ridley (1906-2001)
EVOLUTION AND DEVELOPMENT Generation-I (1949-1954)• Biconvex PMMA PCIOL• Implanted behind iris after ECCE• Diameter – 8.32 mm; Power – 24 DComplications:•Inferior decentration•Posterior dislocation•Inflammation•Secondary glaucoma
Generation-II (1952-1962)• Early Anterior Chamber IOLs• Fixation of lens in angle recess• Advantages:– Less decenteration– Decreased reactionComplications:•Corneal decompensation•Pseudophakic Bullous keratopathy•Uveitis•Secondary glaucoma•UGH syndromeEVOLUTION AND DEVELOPMENT
Generation-III (1953 – 1975)• Iris supported or iris fixated IOLs• Advantages:– It is away from angle structures hencerate of complications like secondaryglaucoma is less.– Rate of dislocation is less.– Less contact with corneal endotheliumhence lesser damage to it.•Complications:•Iris chaffing•Pupillary distortion•Chronic inflammation•CME•Distortion on pupillary dilatation•Endothelial decompensationEVOLUTION AND DEVELOPMENT
• Iris clip lens (Binkhorst) • Iris claw lens (Worst)EVOLUTION AND DEVELOPMENT
• Binkhorst’s another modification (1965)-– Iridocapsular Lens– Posterior haptics in capsular bag with anteriorloops removed.• In 1970 Binkhorst and Worst employed a trans-iridectomy suture for fixation mechanism-MEDALLION lens.EVOLUTION AND DEVELOPMENT
Generation-IV (1963-1990)• Intermediate ACIOLs• Made up of flexible loops with multiple point of fixation• More stable lesser complications• Choyce, Mark VIII, Mark IX, flexible ACIOL, Kelman, Kelman flexibletripod, Kelman quadraflex, Kelman multiplex 4 point fixationChoyce KelmanMark IXEVOLUTION AND DEVELOPMENT
Generation-V (1975-1990)– Improved PCIOLs• Rigid tripod design (John Pierce)• J-looped PCIOL (Steven Shearing)• Modified J-looped PCIOL (Sinskey)• C-looped PCIOL (Simcoe)• One piece PCIOL (Eric Arnott)POSITION•Major advantage-EVOLUTION AND DEVELOPMENT
Generation VI (1990- present) (Modern IOLs) Aspheric IOL Multifocal IOL Accommodative IOL Toric IOL Phakic IOL Aniridia IOL Scleral fixated IOL Glued IOLAdjustable IOLTelescopic IOLElectronic IOLEVOLUTION AND DEVELOPMENT
• Square-edge design• Surface Modifications• UV absorbing materialDESIGN AND MATERIALChromophores are added.Two classes-HydroxybenzophenonesHydroxyphenylbenzotriazoles• Bio-compatible material– Uveal compatibility– Capsular compatibility• Bio-active material
• CONVENTIONAL SPHERICAL IOLs:• A biconvex IOL exhibits positivespherical aberration.• ADD positive spherical aberration to thealready positive corneal sphericalaberrationConventional IOL increasethe spherical aberration of the eyeASPHERIC IOLs
How to overcome this ???• Strategy 1:– Lens with negative spherical aberrations to balance the normally positivecorneal spherical aberrations• Strategy 2:– Lens with minimum spherical aberrations so that no additional sphericalaberration is added to the corneal spherical aberrationsAspheric IOLs attempt to improve pseudophakic vision by controlling spherical aberrations.ASPHERIC IOLs
TYPES:• Anterior prolate surface– Tecnis, Advanced Medical Optics (AMO)• Posterior prolate surface– Acrysof IQ, Alcon Laboratories• Both Anterior and Posterior prolate surfaces– Akreos AO, SofPort AO and L161 AO, Bausch & LombTecnisAcrysof IQSofPort AOAkreos AOASPHERIC IOLs
Restoration of accommodation in pseudophakia-MULTIFOCAL IOLs
Single IOL with two or more focal points. Types Refractive Diffractive Combination of bothMULTIFOCAL IOLs
Bull’s eye lenso Concentric rings of different powerso Central addition surrounded by distance optical power Annulus design 3-5 rings-o Central for distance visiono Near vision ringo Distance vision ringREFRACTIVE MULTIFOCAL IOLs
12345Bright light/ Distance dominant zoneLarge Near dominant zoneLow light/ Distancedominant zoneDistance zoneNear zone Aspheric transitionREFRACTIVE MULTIFOCAL IOLs
REFRACTIVE MULTIFOCAL IOLsMultiple focal points of a refractive MIOL
Silicone MIOLs Array multifocal IOL (AMO) First FDA approved foldable MIOL Acrylic MIOLs ReZoom multifocal IOL (AMO) PREZIOL (Acrylic)(Care Group) Manufactured by Indian company Also available as non foldable PMMA lensREFRACTIVE MULTIFOCAL IOLs
• Tecnis Multifocal IOLs (AMO)– ZM900 (Silicone)– ZA00 (Acrylic)• Optic Diameter 6.0 mm• Optic Type– Modified prolate anterior surface– Total diffractive posterior surface• Diffractive Power +4.0 diopters of near addition (+3.0 Diopters at spectacle plane)Tecnis ZM900 Tecnis ZA900DIFFRACTIVE MULTIFOCAL IOLs
• Acrysof IQ ReSTOR (Alcon) Acrylic diffractive multifocal IOL with apodized design Optic diameter- 6 mm Refractive for distance, and a diffractive lens for near. 16 rings distributed over central 3-6 mm Peripheral rings placed closer to each other Central rings are 1.3 µm elevated are for near vision whereasperipheral 0.2 µm elevated and for distant vision Anterior peripheral surface is modified to act as refractive design Near Addition +3.0 D at IOL plane (+2.5 D at spectacleplane)DIFFRACTIVE MULTIFOCAL IOLs
REFRACTIVE MULTIFOCAL IOLS DIFFRACTIVE MULTIFOCAL IOLSExcellent intermediate and distance vision Excellent reading vision and very gooddistance visionNear vision fair but may not be sufficient to seevery small printFair Intermediate visionPatients who read for prolonged periods of timeor in poor lighting may experience eye fatigue.Patients who do lots of computer work may notaccept it wellPUPIL DEPENDENT LESS DEPENDENT ON PUPILRefractive vs DiffractiveMULTIFOCAL IOLs
Disadvantages• Reduction of contrast sensitivity• Glare, haloes• Less satisfactory visualization of fundus- difficulty in vitreo-retinal procedures• Requires Visual-Cortical Neuro-adaptation• Requires• Accurate biometry• Precise IOL implantation• Astigmatic reductionMULTIFOCAL IOLs
PATIENT SELECTION:Recommended for most but NOT ALL patients.• Not recommended in:– Monofocal lens in the other eye– Pediatric patients– Patient with high ametropia– Patients with unrealistic expectations– Moderate to severe maculardegeneration– Irregular astigmatism or high degreesof regular astigmatism– Previous corneal transplantationsurgery– Keratoconus– Very small or fixed dilated pupils– Where there is doubt about thestability of IOL centration– >83 years of age (Because agereduces contrast sensitivity)MULTIFOCAL IOLs
ACCOMMODATIVE IOLs• Monofocal IOL• Changes position inside the eye as the eyesfocusing muscle contracts• 1 mm of anterior movement of lens = 1.80 D ofaccommodation• Mimicking the eyes natural ability to focus
Silicone Crystalens (Bausch & Lomb) Only FDA approved IOL for correction of presbyopia Hydrophilic Acrylic BioComFold type 43E (Morcher GmbH) 1CU (HumanOptics AG) Tetraflex (Lenstec Inc.)ACCOMMODATIVE IOLs
• Anterior element with a spherical lens to correctthe overall refraction of the eye, and two cubicoptical surfaces for varifocal effect.• Cubic optical elements are fitted by spring-likehaptics fused at the rim to allow a movementperpendicular to the optical axis.Akkolens IOL (Akkolens)ACCOMMODATIVE IOLs
Synchrony Dual-Optic IOL (Visiogen)One piece Silicon foldable IOLTwo optics with high plus anterior andposterior minus lens that are connected byspring like haptics.When zonular tension is released –resultingcompression of optic-spring haptic releasesanterior optic forward.ACCOMMODATIVE IOLs
SmartLENS (Medennium Inc.,Irvine, Calif.) Manufactured from thermodynamic hydrophobic acrylic material which makes it astable, flexible, gel polymer. 2.0 mm rod and injected through a normally sized capsulorhexis Reconfigures itself High refractive index Prevent PCOACCOMMODATIVE IOLs
Sulcus fixated lens Composed of silicone gel between 2 rigidplates with an opening on the front plate With increased vitreous pressure, theplate compress, the polymer bulgesthrough the anterior plateaperture, resulting in increased curvatureand in increased curvature and increasedpower. Accommodation +30 to +50 DNuLens (NuLens Ltd., Israel)ACCOMMODATIVE IOLs
FluidVision IOL (PowerVision, Belmont, Calif.)The annular peripheral haptics- Fluid reservoirThe fluid moves back and forth naturally through thispliable system (Microfluidic technology)The channels in the lens are completely translucentAs the ciliary body and zonular apparatus contract andexpand, that fluid in the peripheral annular haptics isforced radially through a channel into the centre of thelens, causing it to increase its anterior posterior curvatureAverage accommodation +5 DACCOMMODATIVE IOLs
LiquiLens (Vision Solutions) A dual liquid IOL (two immiscible fluids of different refractive indices) Gravity dependent Lower 3/4th – Lower refractive index- Distant vision (in straight gaze) Upper 1/4th – Higher refractive index- Near vision (in downgaze)ACCOMMODATIVE IOLs
Disadvantages of Accommodative IOLs• Smaller optic-more aberrations• Failure of accommodation due to• Fibrosis• Capsular opacification• Anterior• Posterior• Costly
TORIC IOLsVision with Cataract andAstigmatismCataract corrected with IOLbut Astigmatism remainingCataract and Astigmatismboth corrected with Toric IOL
Designed to correct astigmatism Axis of toric power is designed with 2 small hash-marks Pre-operative marking of steep axis (greatercurvature) of cornea (in sitting position) Per-operative alignment of lens with corneal marking 1º misalignment ~ 3.3% loss of cylindrical power Proper positioning of IOL is a mustTORIC IOLs
Two Types• Silicone– STAAR Toric IOL (STAAR Surgicals)• Cylindrical powers: 2.0 D and 3.5 D• Acrylic– AcrySof Toric IOL and Acrysof IQ Toric IOL (Alcon Labs)• Cylindrical powers of 1.5 D, 2.25 D, and 3.0 D– T-flex (Rayner)• 1.0 to 11.0 D in 0.25 D steps– Acri.Comfort (Zeiss)TORIC IOLs
Proposed incision ismarked at the steepest plusmeridian.IOL is loaded into theinjection cartridge withthe toric marks on theanterior surfaceIOL is implanted in thecapsular bag and axis isalignedTORIC IOLs
ROLLABLE IOLs•Ultrathin ~100 µ•Hydrophilic material•Front surface curved•Back surface: series of steps with concentric rings•Open up gradually•Implanted by phakonit technique•Acrismart•Thin Optx ultrachoice•Slimflex lens
PHAKIC IOLs Implantation of IOL without removing naturalcrystalline lens. ADVANTAGE: Preserves natural accommodation Mostly used in Myopic eyes: -5 to -20 DS Also used in Hyperopic eyes Concern in Hyperopes: More chances of endothelial damage Increased risk of angle closure glaucoma Life-long regular follow up required.
Pre-crystalline lens made of silicone or collamer. The length of the lens is calculated by subtracting0.5 mm from the white-to-white limbal diameter. Overall size- 11-13 mm Otical zone - 4.5-5.5 mm Toric model also availableImplantable Collamer Lens (ICL)•COMPLICATIONS:•Constant contact pressure•Cataract•Ciliary body reactions•Prevent free passage of aqueous.- Iridectomyrequired•SPINNAKER EFFECT: Blowing sail of a boatPHAKIC IOLs
VERISYSE/ARTISAN (AMO/OPTECH)– Made of PMMA– convexo-concave– Length = 7.2 – 8.5 mm– Optic size = 5-6 mm– Haptics fixed to iris –clawsIris Fixated Phakic IOLPHAKIC IOLs
Iris Fixated Phakic IOL• ADVANTAGES OVER ICL:– Customized smaller size possible– Can be examined from end-to-end under the slit lampmicroscope throughout the patients life•COMPLICATIONS-•Early post op AC inflammation•Glaucoma•Iris atrophy on fixation sites•Implant dislocation•Decentration•Endothelial cell lossPHAKIC IOLs
TWO TYPES – 4 point fixation– Baikoff’s modification of Kelman type haptic design• NuVita MA20 (Bausch and Lomb) 3 point fixation– Vivarte (IOL Tech)• Separate optic and hapticAngle Fixated Phakic IOLPHAKIC IOLs
PIGGYBACK IOLs An intraocular lens that “piggybacks” onto anexisting intraocular lens or two IOLs areimplanted simultaneously. First IOL is placed in the capsular bag. The second (piggyback) IOL is placed in the bagor sulcus.
Advantages• Easier to place 2nd IOL than to explant IOL & replace it• Lesser risk• More predictable• Can change power with time-by adding IOL or explanting an IOL• Better image quality• Increased depth of focusPIGGYBACK IOLs
COMPLICATIONS Interlenticular opacification (Interpseudophakos Elshnig’s pearls) (RED ROCK SYNDROME) Unpredictable final IOL positionDisadvantagesPIGGYBACK IOLs
ADJUSTABLE IOLs Lens works on the principle of a piston. The haptic-optic junction is a piston such that the optic can be moved forwards orbackwards. It allows multiple adjustments. Useful for pediatric age group.
LIGHT ADJUSTABLE IOLsA photosensitive adjustable foldable 3-piece IOLComposed of subunits (macromers) embedded in a matrix. Focal UV irradiation (365 nm) froma digital light delivery device (Carl Zeiss Meditec) causes polymerization of macromers.Non-polymerised macromers diffuse and migrate into their radiated area causing a powerchangeIrradiating the lens again locks in the desired configurationCalhouns light adjustable IOL.
ANIRIDIA IOLs Various designs Overall size = 12.5 to 14 mm Optic diameter = 3.5 to 5 mm Central clear optic Surrounding colored diaphragm
SCLERAL SUPPORTED IOLs PCIOLS sutured to the sclera through sulcus Widely used technique if there is no capsule oronly sections of peripheral capsule. No endothelial damage Low risk of iris chaffing Some risk of suture breaking Some risk of suture erosion
Techniques of fixation: Ab-interno Ab-externo Single loop Double loopo Single haptic fixationo Double haptic fixationSCLERAL SUPPORTED IOLs
GLUED IOLs Fibrin glue-assisted suture-less posterior chamber IOL implantation technique. INDICATION: Eyes with a deficient posterior capsule. The IOL is introduced through a limbal incision and both the IOL haptics areexternalized under the scleral flap with a 25-gauge MicroSurgical Technologyforceps.
IMPLANTABLE MINIATURE TELESCOPE Miniature implantable Galiliean telescope Implanted in posterior chamber Held in position by haptics loops Contain number of microlenses whichmagnify objects in the central visual field. Improves central vision in ARMD.
• Acts as a telephoto system to enlarge images 2-3 times.• Telephoto effect allows images in the central visual field to not be focused directlyon the damaged macula, but over other healthy areas of the central and peripheralretinaDiseased eye: Image focused ondamaged maculaImplanted eye: Image focused onmacula and peripheryIMPLANTABLE MINIATURE TELESCOPE
DRAWBACKS: Surgically more challenging Difficulty due to the size and weight of the implant Endothelial compromise Blocked peripheral retinal visibility Difficulty in future retinal laser treatments Loss of peripheral visionIMPLANTABLE MINIATURE TELESCOPE
TELESCOPIC IOL Next generation of implantable miniature telescopes. Uses mirrors rather than glass lenses 25 X magnification of central images The LMI (Lipshitz Macular Implant) optics is 6.5mm and onlyslightly thicker than a standard IOL Contains 2 miniature mirrors (a 2.8 mm posterior doughnutshaped mirror that reflects light anteriorly onto a 1.4 mm centralretina–facing mirror which in turn focuses the light on retina). Does not affect peripheral vision.
Ray diagram showing the mirrored deflection of certain light rays that emergewith magnification , the peripheral rays are not engaged by the mirror lens system and passthrough as they would in a standard lens implant thus helping to maintain a relatively normalvisual field .TELESCOPIC IOL
SHAPE OF THINGS TO COME…
• Worlds first implantable lens with artificial intelligence.ELECTRONIC IOLElectro-active switchable elementChange in the molecular configuration of the liquid crystal to alter the optical power of thelensAutomatically adjusts focusing power electronically, in millisecondsMaintains constant in-focus vision for various distances and light environments.Controlled by a micro-sized power-cell with an expected >50 year rechargeable cycle life.CONCEPT: The pupil responds to accommodation by getting smaller. The IOLincludes sensors that detect very small changes in pupil size. The pupillary response toaccommodation is different from the pupillary response to light in regard to amplitude andhow rapidly it occurs in response to accommodation.
LENS: Set to correct distantvision (with dilated pupil)AUTO FOCAL LENS: Electro-active liquidcrystal centre for near vision (with small pupil)BATTERY:Rechargeable Li-ionbatteryMICRO CHIP:Regulates the auto-focallensPHOTO SENSOR: Detectsthe external lightFRONT (CUT-AWAY)VIEW OF ELENZA®ELECTRONIC IOLELECTRONIC IOL
• Remaining safety andtechnological issues…– What happens to the electroniccomponents if the lens is hit with aYAG laser ???– Are any of the materials toxic ???– What if theres leakage ???ELECTRONIC IOL