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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 eye
usually replacing natural crystalline lens during
cataract or refractive surgery to correct optical
power of the eye.
WHAT IS AN IOL ???
HISTORY
Italian scientist Tadini in mid 18th century first considered
intraocular lens implantation.
In 1795, Casamata implanted glass IOL which sank
posteriorly.
English ophthalmologist Sir Nicholas Harold Lloyd Ridley
is credited for first successful IOL implantation on
November 29th 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 D
Complications:• 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 reaction
Complications:• Corneal decompensation
• Pseudophakic Bullous keratopathy
• Uveitis
• Secondary glaucoma
• UGH syndrome
EVOLUTION AND DEVELOPMENT
Generation-III (1953 – 1975)
• Iris supported or iris fixated IOLs
• Advantages:
– It is away from angle structures hence
rate of complications like secondary
glaucoma is less.
– Rate of dislocation is less.
– Less contact with corneal endothelium
hence lesser damage to it.
• Complications:• Iris chaffing
• Pupillary distortion
• Chronic inflammation
• CME
• Distortion on pupillary
dilatation
• Endothelial decompensation
EVOLUTION 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 anterior
loops 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 flexible
tripod, Kelman quadraflex, Kelman multiplex 4 point fixation
Choyce KelmanMark IX
EVOLUTION 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 IOL
Adjustable IOL
Telescopic IOL
Electronic IOL
EVOLUTION AND DEVELOPMENT
NEWER IOLs
• Square-edge design
• Surface Modifications
• UV absorbing material
DESIGN AND MATERIAL
Chromophores are added.
Two classes- Hydroxybenzophenones
Hydroxyphenylbenzotriazoles
• Bio-compatible material– Uveal compatibility– Capsular compatibility
• Bio-active material
ASPHERIC IOLs
Human eye- Aspheric Optics
Cornea- Positive spherical aberration
Young crystalline lens- Negative spherical
aberration
Ageing- Crystalline lens gains Positive
spherical aberration
+ -
++
ASPHERIC IOLs
• CONVENTIONAL SPHERICAL IOLs:
• A biconvex IOL exhibits positive
spherical aberration.
• ADD positive spherical aberration to the
already positive corneal spherical
aberrationConventional IOL increase
the spherical aberration of the eye
ASPHERIC IOLs
How to overcome this ???
• Strategy 1:
– Lens with negative spherical aberrations to balance the normally positive
corneal spherical aberrations
• Strategy 2:
– Lens with minimum spherical aberrations so that no additional spherical
aberration is added to the corneal spherical aberrations
Aspheric 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 & Lomb
TecnisAcrysof IQSofPort AOAkreos AO
ASPHERIC IOLs
METHODS
Monovision Multifocal IOLAccommodative
IOL
Restoration of accommodation in pseudophakia-
MULTIFOCAL IOLs
Single IOL with two or more focal points.
Types
Refractive
Diffractive
Combination of both
MULTIFOCAL IOLs
Bull’s eye lenso Concentric rings of different powers o Central addition surrounded by distance optical power
Annulus design 3-5 rings-
o Central for distance visiono Near vision ringo Distance vision ring
REFRACTIVE MULTIFOCAL IOLs
12345
Bright light/ Distance dominant zoneLarge Near dominant zone
Low light/ Distance dominant zone
Distance zone
Near zone Aspheric transition
REFRACTIVE MULTIFOCAL IOLs
REFRACTIVE MULTIFOCAL IOLs
Multiple 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 lens
REFRACTIVE MULTIFOCAL IOLs
DIFFRACTIVE MULTIFOCAL IOLs
Distance vision (white arrow) Near vision (blue arrow)
DIFFRACTIVE 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 ZA900
DIFFRACTIVE 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 whereas
peripheral 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 spectacle
plane)
DIFFRACTIVE MULTIFOCAL IOLs
REFRACTIVE MULTIFOCAL IOLS DIFFRACTIVE MULTIFOCAL IOLS
Excellent intermediate and distance vision Excellent reading vision and very good distance vision
Near vision fair but may not be sufficient to see very small print
Fair Intermediate vision
Patients who read for prolonged periods of time or in poor lighting may experience eye fatigue.
Patients who do lots of computer work may not accept it well
PUPIL DEPENDENT LESS DEPENDENT ON PUPIL
Refractive 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 reduction
MULTIFOCAL 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 macular
degeneration
– Irregular astigmatism or high degrees
of regular astigmatism
– Previous corneal transplantation
surgery
– Keratoconus
– Very small or fixed dilated pupils
– Where there is doubt about the
stability of IOL centration
– >83 years of age (Because age
reduces contrast sensitivity)
MULTIFOCAL IOLs
ACCOMMODATIVE IOLs
• Monofocal IOL
• Changes position inside the eye as the eye's
focusing muscle contracts
• 1 mm of anterior movement of lens = 1.80 D of
accommodation
• Mimicking the eye's 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
ACCOMMODATIVE IOLs
Working Mechanism of CrystaLensACCOMMODATIVE IOLs
• Anterior element with a spherical lens to correct
the overall refraction of the eye, and two cubic
optical surfaces for varifocal effect.
• Cubic optical elements are fitted by spring-like
haptics fused at the rim to allow a movement
perpendicular to the optical axis.
Akkolens IOL (Akkolens)ACCOMMODATIVE IOLs
Synchrony Dual-Optic IOL (Visiogen)
One piece Silicon foldable IOL
Two optics with high plus anterior and
posterior minus lens that are connected by
spring like haptics.
When zonular tension is released –resulting
compression of optic-spring haptic releases
anterior optic forward.
ACCOMMODATIVE IOLs
SmartLENS (Medennium Inc.,Irvine, Calif.)
Manufactured from thermodynamic hydrophobic acrylic material which makes it a
stable, flexible, gel polymer.
2.0 mm rod and injected through a normally sized capsulorhexis
Reconfigures itself
High refractive index
Prevent PCO
ACCOMMODATIVE IOLs
Sulcus fixated lens
Composed of silicone gel between 2 rigid plates with an opening on the front plate
With increased vitreous pressure, the plate compress, the polymer bulges
through the anterior plate aperture, resulting in increased curvature and in increased curvature and increased power.
Accommodation +30 to +50 D
NuLens (NuLens Ltd., Israel)ACCOMMODATIVE IOLs
FluidVision IOL (PowerVision, Belmont, Calif.)
The annular peripheral haptics- Fluid reservoir
The fluid moves back and forth naturally through this
pliable system (Microfluidic technology)
The channels in the lens are completely translucent
As the ciliary body and zonular apparatus contract and
expand, that fluid in the peripheral annular haptics is
forced radially through a channel into the centre of the
lens, causing it to increase its anterior posterior
curvature
Average accommodation +5 D
ACCOMMODATIVE 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 IOLs
Vision with Cataract and Astigmatism
Cataract corrected with IOL but Astigmatism remaining
Cataract and Astigmatism both 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 (greater
curvature) 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 must
TORIC 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 is marked at the steepest plus meridian.
IOL is loaded into the injection cartridge with the toric marks on the anterior surface
IOL is implanted in the capsular bag and axis is aligned
TORIC 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 natural
crystalline 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.
Posterior Chamber
Iris fixatedAngle fixated
PHAKIC IOLs
Examples:
• Implantable collamer lens (ICL) (VISIAN; STAAR)• Phakic refractive lens (Medennium)• Sticklens
COMPLICATIONS:– Endothelial cell damage– Inflammation– Pigment dispersal– Elevated IOP– Cataract
Posterior Chamber Phakic IOLsPHAKIC IOLs
Pre-crystalline lens made of silicone or collamer.
The length of the lens is calculated by subtracting 0.5 mm from the white-to-white limbal diameter.
Overall size- 11-13 mm
Otical zone - 4.5-5.5 mm
Toric model also available
Implantable Collamer Lens (ICL)
• COMPLICATIONS:
• Constant contact pressure
• Cataract
• Ciliary body reactions
• Prevent free passage of aqueous.- Iridectomy required
• SPINNAKER EFFECT: Blowing sail of a boat
PHAKIC 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 –claws
Iris 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 lamp
microscope throughout the patient's life
• COMPLICATIONS- • Early post op AC inflammation• Glaucoma• Iris atrophy on fixation sites• Implant dislocation• Decentration• Endothelial cell loss
PHAKIC 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 haptic
Angle Fixated Phakic IOLPHAKIC IOLs
COMPLICATIONS –
Endothelial cell loss
Irregular pupil
Iris depigmentation
Post-op inflammation
Halos and glare
Surgical induced astigmatism
PHAKIC IOLs
PIGGYBACK IOLs
An intraocular lens that “piggybacks” onto an
existing intraocular lens or two IOLs are
implanted simultaneously.
First IOL is placed in the capsular bag.
The second (piggyback) IOL is placed in the bag
or 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 focus
PIGGYBACK IOLs
COMPLICATIONS
Interlenticular opacification (Interpseudophakos Elshnig’s pearls) (RED ROCK SYNDROME)
Unpredictable final IOL position
Disadvantages PIGGYBACK 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 or backwards.
It allows multiple adjustments.
Useful for pediatric age group.
LIGHT ADJUSTABLE IOLs
A photosensitive adjustable foldable 3-piece IOL
Composed of subunits (macromers) embedded in a matrix. Focal UV irradiation (365 nm) from a digital light delivery device (Carl Zeiss Meditec) causes polymerization of macromers.
Non-polymerised macromers diffuse and migrate into their radiated area causing a power change
Irradiating the lens again locks in the desired configuration
Calhoun's 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 or
only 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 loop
o Single haptic fixationo Double haptic fixation
SCLERAL 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 are externalized under the scleral flap with a 25-gauge MicroSurgical Technology forceps.
IMPLANTABLE MINIATURE TELESCOPE
Miniature implantable Galiliean telescope
Implanted in posterior chamber
Held in position by haptics loops
Contain number of microlenses which
magnify 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 directly on the damaged macula, but over other healthy areas of the central and peripheral retina
Diseased eye: Image focused on damaged macula
Implanted eye: Image focused on macula and periphery
IMPLANTABLE 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 vision
IMPLANTABLE 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 only
slightly thicker than a standard IOL
Contains 2 miniature mirrors (a 2.8 mm posterior doughnut
shaped mirror that reflects light anteriorly onto a 1.4 mm central
retina–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 emerge with magnification , the peripheral rays are not engaged by the mirror lens system and pass through as they would in a standard lens implant thus helping to maintain a relatively normal visual field .
TELESCOPIC IOL
SHAPE OF THINGS TO COME…
• World's first implantable lens with artificial intelligence.
ELECTRONIC IOL
Electro-active switchable element
Change in the molecular configuration of the liquid crystal to alter the optical power of the
lens
Automatically adjusts focusing power electronically, in milliseconds
Maintains 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 IOL
includes sensors that detect very small changes in pupil size. The pupillary response to
accommodation is different from the pupillary response to light in regard to amplitude and
how rapidly it occurs in response to accommodation.
LENS: Set to correct distant vision (with dilated pupil)
AUTO FOCAL LENS: Electro-active liquid crystal centre for near vision (with small pupil)
BATTERY: Rechargeable Li-ion battery
MICRO CHIP: Regulates the auto-focal lens
PHOTO SENSOR: Detects the external light
FRONT (CUT-AWAY) VIEW OF ELENZA®
ELECTRONIC IOL
ELECTRONIC IOL
• Remaining safety and technological issues…
– What happens to the electronic
components if the lens is hit with a
YAG laser ???
– Are any of the materials toxic ???
– What if there's leakage ???
ELECTRONIC IOL
Thank you…