Nawat Watanachai2013

1949 Sir Harold Ridley (UK)

1952 : Baron (FRA)

1953 : Edward Epstein (USA)

More than 250 models of IOL to be chosenWhich one is the best choice?

Which one is the best (+affordable)

choice?Patient’s satisfaction

▪ Good VA/ wide range of vision▪ Less aberration/ glare▪ safe▪ Reasonable price

Which one is the best (affordable) choice? Doctor’s satisfaction

▪ Easy to handle/ insert/ remove▪ Chemically inert/ noncarcinogenic/ nonallergic▪ Low bacteria and fungus adherence▪ Durable▪ Others :

▪ high RI/ absorp UV/ transparent for visible light

Materials Optical part : clear/ biocompat/ durable Haptic part

Designs Optical part : less PCO/ less aberration/

UV filter Haptical part : stability/ easily

insert+remove

Optics Glass Silicone-based Acrylate-Methacrylate-Based

Haptics Silicone-based Acrylate-Methacrylate-Based Polyamide Polyethylenglycolterephthala

te Polypropylene Polyimide

Glass Silicone-Based Acrylate-Methacrylate-Based

Polymethylmethacrylate monomer (PMMA) Rohto, PH55MB, P366UV, EZE55, SF65

Acrylic polymers Hydrophilic Acrylic polymers

Hydrogel

Hydrophobic Acrylic polymers Acrysof, Akreos, Sensar, Clariflex, Tecnis

Refractive index = 1.49AdvantagesCheap Transmit a broad light spectrum Surface modification Good biocompatibility Large optic center

Disadvantages Large incision size Brittle Monomeric release Not autoclavable Injure cornea

one-piece PMMA PC-IOLPH55, MC60BM, RohtoRE06F,

Epoch651A,Crystalfor Scleral fixationP366UV, SF65AC IOLS122UV

Disadvantages The lowest threshold for YAG laser

damage Discoloration of lens to a tan-brown color Irreversible adherence to silicone oil Foggy when exposed to airflow Slippery when wet

SI-30 design (AMO)SI-40 design (AMO)CeeOn Edge 911 (Pfizer)Clariflex (AMO)SoFlex SE (B&L)

Advantages Good biocompatibility,optical quality Foldable Good laser resistance Little or no surface alteration or damage

from folding Low damage potential when

touching the corneal endothelium

The Hydroview lens (B&L)The MemoryLens (Ciba Vision)The CenterFlex Lens (Rayner)

Developed for IOLPure acrylic polymer (flexibility) +

Methacrylic polymer (durability)

Advantages Foldable High refractive index (1.55) Good biocompatibility, optical quality High tensile strength VS hydrophilic Low water content/ no hydration require

Disadvantages Limit (very) long term

study Easily get forceps marks Sticky surface

PMMA Hydrophilic acrylic

Hydrophobic acrylic

silicone

RI 1.49 1.45-1.52 1.45-1.55 1.41-1.46

Biocompatibility

+ ++ ++ +++

Surface smoothening

++ + + +

Surface modification

- +++ +++ ++

PMMA Hydrophilic acrylic

Hydrophobic acrylic

silicone

Incision size

Large Smallest Smallest small

Non-Slippery when wet

+ + + --

Unfolding 0 + - -

Less mechanical corneal damage

-- ++ ++ ++

PMMA Hydrophilic acrylic

Hydrophobic acrylic

silicone

Less pigment adhesion

++ - ++ ++

Less LEC outgrowth

++ -- ++ +

Laser resistance

- ++ ++ --

Less Silicone oil adhesion

++ + + ---

Optical part : clear/ less PCO/ less aberration

Haptical part : stability/ easily insert+remove

germinal cells migrate centrally from equator contribute to the formation of

the nucleus , epinucleus and cortex throughout life

Square posterior edge

Square posterior edge360 barrier

ProTEC™ 360° Edge Design The 360° square edge Uninterrupted contact

with the posterior capsular bag even at the haptic-optic junction

The frosted-edge design minimizes edge glare

35

PCO

Acrysof

Akreos Tecnis

Posterior square edge

+ + +

IOL design : Spherical aberration

Spherical aberrations of the human eye vary with age

Cornea : always gives positive spherical

aberrations

Young lens :negative spherical aberrations old lens : positive spherical aberrations

glare,reduce contrast

In aviation-type visual performance testing, vision in low-light conditions (5 mm pupil)Does not allow a lens to bring light rays to an ideal focal pointThe effect may be a reduction in contrast sensitivity or visual function*

IOL With Residual Spherical Aberration*

IOL With No Residual Spherical Aberration

Spherical IOL The thicker the lens, the

greater the spherical aberration More power, increase

IOL thickness IOL thickness <-- RI

AcrySof (+20D) Silicone (+20D)

* DA Atchison, JCRS 1991

Aspheric optics align the light rays to compensate for Aspheric optics align the light rays to compensate for positive corneal spherical aberration, resulting in enhanced positive corneal spherical aberration, resulting in enhanced image quality.image quality.

*Smith, G., Atchinson D.A., (1997) The Eye and Visual Optical Instruments. Cambridge University Press, Cambridge, United Kingdom, pp. 667.

Aspheric IOL

Acrysof IQ ( SN 60 WF) (Alcon)

Akreos AO (Bausch & Lomb)

Tecnis Z 900 (AMO)

IQ’s posterior aspheric optic Compensates for spherical aberration by

addressing over-refraction at the periphery No increase in edge thickness Lenc become thinner

Aspheric IOL

Trim both anterior and posterior surfaces

Creates asphericity by elevating the peripheral portion of the anterior lens surface

Edge thickness of approximately .60 mm

Spherical aberration

Acrysof Akreos Tecnis

Correction area

Trim posterior center

Trim anterior / posterior center

Add anterior rim

Lens thickness

Thinner at center

Thinner at center

Thicker at rim

511. Schwiegerling J. Survey of Ophthalmology, 2000.

52

may negatively impact: Visual acuity Contrast sensitivity Functional vision

Abbe numbers

The higher the Abbe number- lower the chromatic aberration - higher the retinal image quality

Negishi K, et al. Arch Ophthalmol .2001.

A higher Abbe number is better: this means less chromatic aberration and better optical performance

Acrysof (Alcon) 37Akreos (B&L) 47Tecnis (AMO) 55

A higher Abbe number is better: this means less chromatic aberration and better optical performance

Acrysof (Alcon) 37Akreos (B&L) 47Tecnis (AMO) 55

551. Schwiegerling J. Survey of Ophthalmology, 2000.

Acrysof (Alcon)

Akreos (B&L)Tecnis

(AMO)

ALL CHECKED

UV blocker (350-400 nm)Blue blocker (blue 400-480 nm)

Filters for invisible UV rays some visible blue rays

Block visible blue rays? Blue ray :

7% of cone related photopic vision 35% of rod related scotopic vision

Patients with blue light-filtering IOLs had faster response times in driving Gray R. J Cataract Refract Surg. 2011

Blue light-filtering IOLs helped to lower glare disability and increase photostress recovery time Hammond. Clin Ophthalmol. 2010

Block only the UV lightNOT the BLUE

Blue light is proven to be essential for optimal scotopic vision*

Blue light provides 35% of scotopic sensitivity*

*Mainster MA. Br J Ophthalmol. 2006. 61

Interest in blocking blue-light is motivated by the unproven hypothesis that phototoxicity from environmental light exposure can cause AMD*

10 of 12 major epidemiological studies show no correlation between AMD and lifelong light exposure

62 Mainster MA. Presented at ASCRS .2009.

Acrysof Akreos Tecnis

A 118.7 118.5 118.8

Hydrophobic acrylic

yes yes yes

RI 1.55 1.458 1.47

Abb no 37 47 55

UV blocker + + +

Blue blocker

+ - -

Acrysof Akreos Tecnis

Haptic angulation

0 10 5

Haptic shape

J Loop L

Block Spherical aberration

YesPost.trim

YesAnt. + Post.trim

YesAnt.add

Thickness at same power

thinnest fair thickest

Toric IOLsMultifocal IOLsAccommodative IOLs IOLs for very small incision Adjustable power IOLs Phakic IOLs

To reduce pre-existing astigmatismNeed appropriate centration, fixation

and stability without rotational movement

Preexisting regular astigmatism 0.75>D More problem if axis is away from 90/

180’Regular and smooth keratoscopic

mires with orthogonal steep and flat meridians

Irregular astigmatismDistorted keratometryA lifelong patient history of

satisfaction with spectacular cylindrical corrections

Large eyes (white-to-white distance > 12 mm)

Postoperative rotation or decentration will cause problems

negative effect can occur if the lens axis rotates by more than 30’

Coming soon

My opinion : when to consider toric IOL Astigmatism >1.5 at 90’ or 180’ Astigmatism 1.0 at other axes

distance and near visionRequire

astigmatism controlprecise biometry

Types of multifocal IOLs Refractive multifocal IOLs

▪ Spheric▪ Aspheric Diffractive multifocal IOLs

Array Design multifocal IOLs (AMO) Three-piece Silicone with PMMA haptic zonal multifocal optic with 5 concentric

zones▪ Zone 1, 3,5 – distance▪ Zone 2,4 -near

Array Design multifocal IOLs (AMO) Anterior spheric refractive surface and

multiple posterior refractive surface Power 0-5.0 D vision

▪ Distance vision 50 %▪ Intermediate vision 13 %▪ Near vision 37 %

The ReSTOR (Alcon) Single-piece The diffractive grating is present in the center 3.6

mm The largest diffractive step is at the lens center

▪ send most energy to the near focus As the step move away from the center,they

gradually decrease in size ,blending into the periphery▪ sending more proportion of energy to the distance focus

▪ When the pupil is small or medium size▪ provides appropriate near and distant

vision▪ large pupil situations

▪ becomes a distant-dominant

Problems and complications loss of contrast sensitivity pupillary apertures <2 mm

decrease in distance VA decentered > 2 mm

loss of near VA visual performance is minimally

affected by decentration and changing pupillary size

Problems and complications (cont’d) Ghosting of images and glare from

oncoming light

Refractive Diffractive

Near VA - +

Distance VA = =

Contrast sensitivity

better worse

glare Less more

Array AcrysofReSTORTecnisMF

▪ Pros▪ Offer ranges of vision

▪ Cons▪ Not offer good vision in all ranges▪ 30% still need reading glasses

▪ PCO will cause more visual problems▪ More glare▪ Less contrast sensitivity

▪ Need good IOL positioning Round CCC Clear capsular bag Tilt < 5-6’

Price tag

To restore accommodation forward movement of the optic during

accommodationIt is still not known whether the

ability of these new IOL design will not be impair by long-term postoperative fibrosis/ opacification within the capsular bag

CrystaLens The lens is hinged adjacent to

the optic

with accommodative effort▪ redistribution of ciliary body

mass▪ result in increased vitreous

pressure ▪ move the optic forward

anteriorly within the visual axis

▪ creating a more plus powered lens

synchrony IOL (Visiogen Inc.) One-piece silicone lens The anterior lens has a high plus power

beyond that required to produce emmetropia(30-35 D)

the posterior lens has a minus power to return the eye to emmetropia

The distance between the two optics• minimum in the un-accommodated state• maximum in the accommodated state

No long term data

FluidVisionPocket filled

with clear liquid silicone

• Calhoun lens•University of California at San Francisco, San Francisco, California

There is no BEST IOL for allFind the proper one for each patients