Step by Step Iris Clip

Dr Rahul AchlerkarDr Vijay Shetty

HISTORYItalian scientist Tadini in mid 18th century first considered

intraocular lens implantation.

In 1895, 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

Why the Iris? Iris is the ”toughest” tissue within the eye

The iris is a resilient tissue.

Pigmented tissue in nature is usually associated with being “tough”

Iris Macroscopic appearance.1. Ciliary zone. It presents series of radial streaks

due to underlying radial blood vessels

2. Pupillary zone. Is relatively smooth and flat.

The Iris consists of Pupil BorderThe sphincter mechanism of the

pupil border is functioning due to a smooth muscle with a great constricting and dilating capacity.

Anatomy of the IrisThe stroma connects to a sphincter muscle (sphincter pupillae)

It contracts the pupil in a circular motion, and a set of dilator muscles (dilator pupillae) which pull the iris radially to enlarge the pupil, pulling it in folds. 

Anatomy of the IrisSphicnter pupillae muscle

Dilator pupillae muscle

Pupil Dilatation Mechanism (3 concentric areas)The central part is highly mobile dilatable and constrictable

The paracentral thickened area lies at two-third from the iris base

The iris base is immobile.

Binkhorst’s (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

EVOLUTION AND DEVELOPMENT

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

Discovery of the Iris Claw principle

Using an early model, the Slotted Medallion lens, Jan Worst sometimes observed that some iris tissue was caught in the slot of his lens.

This clasping of iris tissue proved to be a serendipitously discovered new possibility for stable fixation of the IOL.

Once the efficacy of this additional fixation method had been proven in a number of cases additional iris stitching seemed no longer necessary.

Peripheral Iris Supported IOLs

The design was relatively simple

One piece, one material, without additional loops.

The fixation mechanism is based on the enclavation of a fold of iris tissue.

In 1997 an improved vaulted design of the ARTISAN® Aphakia Lens was introduced with a number of new characteristics.

The lens configuration was made vaulted to create distance to the iris

Enclavation was made easier by using a lens with a larger and oval aperture between optic and haptics than the original circular shape.

Worst Iris Claw® IOL (left) ARTISAN®/ Iocare Aphakia IOL

Lens Design“Iris Bridge”

support The fixation points of these

lenses are located in the virtually immobile part of the peripheral iris

The “iris bridges” form a shield and protect the cornea from touching the PMMA haptics of the IOL.

The Iocare /ARTISAN® Aphakia IOL

Since the start of the original design of the Iris Claw lens (1978), the fixation concept of this lens has remained unchanged

Only the lens design has slightly changed in 1997 (vaulted design and oval aperture).

Worst Iris Claw design Vaulted IoCare/ ARTISAN® design

Unrestricted dilatation

The haptics (fixation arms) attach to the midperipheral virtually immobile iris stroma, thus allowing the pupil unrestricted ability to dilate &constrict

Fluorescein angiographic studies by Strobel1 and Izak2 have shown no leakage of the iris vessels at the enclavation sites.

Only a few cases of iris atrophy in the area of the fixation have been reported in the literature

Unrestricted dilatation

Lens Manufacturing

Compression Molding Technology During the compression molding process the molecular

structure of PMMA is enhanced by redistributing the molecules into longer chains, resulting in a much stronger material.

Compression Molding Technology

PMMA before and after compression molding.

Extreme flexibility of the hapticsCompression Molding Technology gives a high

tensile strength, combined with flexibility of the lens haptics. The risk of fracture is minimal.Proprietary Tumbling ProcessThe proprietary tumbling process gives a special surface

treatment to IOLs.An ultra smoothness of the IOL is the result.

Technical SpecificationsLens type: AC/ PC Iris

Fixation (“ Iris Bridge”)Lens material: Perspex-CQ

UVFixation: Mid-Peripheral,Iris Stromal SupportOverall diameter: 8.5 mmBody diameter: 5.4 mm

Technical Specifications

Optic diameter: 5.0 mm

Total height: 0.76 mmWeight: 8mg in air

(20D lens)Sterilisation: Ethylene

oxideAC Depth: 3.3 mmA-constant: 115.0

(Ultrasound)115.7 (Optical)

Powers available: +2.0 D to +30.0 D (1.0 D increments)

+14.5 D to +24.5 D (0.5 D increments).

Versatility AC or PC fixation

Paediatric Aphakia IOL

Lens type: AC Iris Fixation (“Iris bridge”);

Lens material: Perspex-CQ UV;

Overall diameter: 6.5 mm;Body diameter: 4.4 mm;Optic diameter: 4.4 mm;Total height: 0.56 mm;Weight: 8mg in air (20D

lens);- 6.5mm overall size

Benefits The “iris bridge” protects the

endothelium from touching the PMMA

Safe clearance from vital structures (corneal endothelium);

Unrestricted pupil dilatation and constriction (sphincter independent)

Excellent centration; once fixated the lens will not decenter

“vaulted” lens configuration

Iris clip Angle Supported lens

Sclera sutured PC IOL

Safety Excellent,predictable

Angle relatedcomplications

Sutures can erode andrefraction unstable

Outcomes Excellent,predictable

Angle relatedcomplications

Refraction not predictable,lens tilt, hemorrhage andsecondary glaucoma

Clinical History 30+ years Removed from manymarkets

30+ years

Toric option Yes No No

Suturingrequired IOL

No No Yes

Fixation options

Iris Angle Sclera, sulcus, iris

Next Generation of Iris Fixated IOLs

Foldable lens body thus permitting a small incision.

Small incision, 3.2 mmControlled folding and

unfolding Reversible treatment Aspherical edge design Large optical zone

Toric iris clip IOLs

PMMAOptic –PolysiloxaneHaptic-PMMA

Other IndicationsIris fixated Custom-made IOLs include lenses for the

treatment of unique ocular conditions likeColoboma, Diplopia

There are two categories of Custom-made lenses: Iris Reconstruction IOLs (made of coloured & clear PMMA) Pupil Occluder for Diplopia Correction (made of black

PMMA).

Iris fixated Reconstruction IOLs

IOLs with coloured haptics (blue, brown, green or black) are ideal for anterior segment reconstruction when iris damage has occurred or is already congenitally present.

Even large iris colobomata can be covered by the coloured haptic of the IOL.

Pupil Occluder for Correction of DiplopiaAnother application of the iris base Fixation Concept is Pupil

Occlusion in case of intolerable Diplopia due to ocular muscle imbalance.

The Pupil Occluder functions as a cover over the pupil to prevent double images.

Occluder is made of black polycarbonate and covers the pupil completely

Due to the vaulted configuration it can be applied in both phakic and aphakic eyes

8.5mm overall size Pupil Occluder in situ

The main features are:

Minimal risk surgeryThe anatomy of the iris and its specific features allow surgery

with minimal risks. Fixation is performed to the iris periphery.

Pressure free iris fixation

No iris atrophy when the recommended surgical technique is used

indicationsSenile cataract with severe zonular dialysis

Traumatic cataract

Congenital or juvenile cataract with subluxation

Secondary implantation after aphakia.

Contraindications

Recurrent or chronic iritisRubella cataract Retina and optic nerve defects; Corneal distrophy (except in preparation for penetrating

keratoplasty)Acute inflammationSevere iris atrophy Uncontrolled chronic glaucoma

Technique for AC iris fixated iol

Video of AC iris clip IOL

Enclavation Forceps

Enclavation Needle

Foldable Iris clipPerform a mainincision of 3.2 mm Insertion Spatula

How to properly Enclavate the iris

Notice that the “claws” are perfectly aligned.

PROPER technique

WRONG technique

See damage caused by improper enclavation

Peripheral iridectomy or iridotomy

Although all Aphakia IOLs are vaulted ,it is highly recommended to perform an iridectomy or iridotomy.

The pigment layer needs to be perforated completely

An iridectomy or iridotomy has to be made to avoid a postop pupil block

It can also be used to manage an unwanted iris prolapse.

Retropupillary Fixation Technique

As recommended by A. Mohr, M.D.

A technique is recommended with a 12 o’clock frown incision (corneo-scleral 5.5mm)

Authors from Bursa-Turkey use a scleral tunnel incision to avoid the formation of postoperative astigmatism.

The width of the incision should be 5.5 mm.

Do not constrict the pupil

Leave the pupil at a minimum size of approximately 3mm to allow the lens to reach the retropupillary position through the pupil.

use of high viscosity viscoelasticInject a small amount of viscoelastic from the periphery of the

eye, but never directly into the pupillary area

Implantation of the iol

The IOL will be inserted into the anterior chamber with the convex side downwards (upside down) holding it in the forceps.

With a manipulator, the IOL will be brought into the horizontal position from 3 o’clock to 9 o’clock.

iol fixation on the iris

After the IOL has been brought behind the iris and the pupil is constricted, the IOL will be lifted and tilted slightly in order to show the contour of the“claws” through the iris stroma.

A fine spatula is inserted and exerts gentle pressure on the slotted centre of the lens haptic, the “claw”.

The same manoeuvre is now repeated on the other side.

The IOL is now retropupillary fixated.

VIDEO OF RETROFIXTED IRIS CLIP

Peripheral iridectomy

It is not absolutely essential and strictly recommended to perform an iridectomy

removal of all viscoelastic Carefully remove all of the viscoelastic to avoid a high pressure.Suturing Close the incision with sutures.

VIDEO PUPILOPLATY

INTRA operative problems

Macular burnsThe light of the surgical

microscope may cause damage to the macula during surgery

PreventionUse a protecting filter on the

microscope or cover the pupil with a surgical sponge .

Iris Prolapse

An iris prolapse occurs more often when making a corneoscleral incision, than making a tunnel incision

PreventionPlace one or two sutures

after the insertion of the lens and before the enclavation.

SolutionMake an iridectomy as soon

as possible.

Lens not centered properly

A decentered IOL may cause glare or halos

PreventionCheck the centration of the

IOL on the pupil after removal of the viscoelastic.

SolutionIt can be corrected by re-

enclavation

Insufficient Iris Enclavation

Insufficient Iris Enclavation can lead to postoperative dislocation

PreventionUse the specific instruments

developed for the Aphakia IOL implantation

SolutionRe-enclavate a dislocated

IOL

Subluxation

After ocular trauma or spontaneously, luxation of one of the claws can occur, leading to subluxation of the IOL

when a too small amount of iris tissue is enclavated, The IOL has to be reenclavated

immediately to minimize endothelial damage.

Secondary surgical interventions

Lens repositioningIs necessary after lens decentration and in cases in which a

preventive repositioning was performedin subjects with too small amounts of enclavated iris tissue.

Lens replacementAn IOL can be removed and replaced by a new Aphakia IOL.

Articles of Interest

Long-term follow-up of the corneal endothelium after artisan lens implantation for unilateral traumatic and unilateral congenital cataract in children: two case series.

Odenthal MT, Sminia ML, Prick LJ, Gortzak-Moorstein N, Volker -Dieben HJ. Cornea 2006; 25(10):1173-7.

RESULTS: Endothelial cell loss 10.5 yrs after iris fixated IOL implantation for traumatic cataract was substantial & related to the length corneal scar of original trauma . In children operated for congenital cataract , no difference was found in CECD in operated & unoperated eyes after 9.5 yrs after artisan iols

Penetrating keratoplasty combined with posterior Artisan iris-fixated intraocular lens Implantation

Dighiero P, Guigou S, Mercie M, Briat B, Ellies P, Gicquel JJ. Acta Ophthalmol Scand. 2006; 84(2):197-200

Dr Vijay Shetty Dr Suhas Haldipurkar

Dr Shweta Rao Dr Maninder Singh Setia

A RETROSPECTIVE ANALYSIS OF IOL POWER CALCULATION AND

POSTOPERATIVE RESULTS OF IRIS CLIP IOL

WOC 2011 Abu Dhabi

AIM

• To study the post operative visual outcome in retrofixed iris clip IOLs with respect to uncorrected visual acuity and best corrected visual acuity

• To study the refractive outcome in iris clip IOLs using IOL master and various formulae

• To study the prevalance of PXF, Trauma, Marfan’s syndrome, retinal tears, cystoids macular oedema and retinal detachment in patients who underwent iris clip IOL

CONCLUSION

Retrofixed iris clip IOL is a relatively a safe procedure in eyes with no capsular support. Trauma, PXF and Marfan’s syndrome were associated in 41%, 14% and 14% respectively .IOL was required in 5/26 (19%). Similar IOL refixation was noted in both horizontal and vertical fixation.CME: 2/26, Uveitis: 1/27, Retinal Hole: 1/27 in our population,

Hoffer Q formula predicted the IOL power most accurately for iris clip IOLs consistently in eyes with varied axial length followed by Holladay and SRK T.

Books1. Cataract and IOL Daljit Singh, Jan Worst, Ravijit Singh, Indu R. Singh. 1993 Chapter 20: Iris Claw Lens, page 82-972. A Colour Atlas of Lens Implantation Chapter 13: Iris-fixated lenses, evolution and application – Jan

Worst, page 79-873. Iris Claw Lens or Lobster Claw Lens of Worst Alpar JJ / Fechner PV, 1986

Thanks