newer iols

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


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


• Iris clip lens (Binkhorst) • Iris claw lens (Worst)


• 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.


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


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-


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


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



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


DIFFRACTIVE MULTIFOCAL IOLs

Distance vision (white arrow) Near vision (blue arrow)


• 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


• 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)


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


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


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…

newer iols

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