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The Cataract Surgery Nightmare:When It Doesn’t Go To PlanDr Michael Forrest Northside Eye Specialists, NundahSenior Lecturer, The University of Queensland Visiting Ophthalmologist, Mater Hospital, Brisbane

Australian Vision Convention April 13, 2012

Is 99% good enough?Or 99.9%%?

Or 99.99%

! 135000 cataract procedures performed in Australia last year

! small changes in the rate of a given complication translate into a largechange in the number of people affected

! at 1% 1350

! at 0.1% 135

! at 0.01% ...

Selected complications

! endophthalmitis

! IFIS

! dropped nucleus

! corneal decompensation

! refractive complications

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Acute Post-Operative BacterialEndophthalmitis

Endophthalmitis

! arguably the most-feared complication of cataract surgery

! can result in blindness and even loss of the eye

! reported incidence varies from 0.04% to 0.22%

! 70% Staphylococcus epidermidis, 10% S.aureus, 9%Streptococcus, 5.9% Gram negative

! in EVS only 53% of patients retained 6/12 or better

EndophthalmitisManagement

! vitreous biospy

! needle aspirate may be adequate if VA is HM or better

! vitrectomy required if LP or worse

! vitrectomy may be indicated if

! rapidly worsening

! diabetic or immunocompromised

! intravitreal antibiotics

! Vancomycin and Ceftazidime

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! in EVS only 53% of patients retained 6/12 or better

EndophthalmitisProphylaxis?

! clear corneal incisions favoured by most surgeons but associated withslightly increased risk

! move towards smaller incisions may reduce risk somewhat

! before the ESCRS Endophthalmitis Study, only topical PovidoneIodine was proven to decrease risk

! Multiple other strategies adopted, including Fluorquinolone ABs pre-operatively, ABs in irrigating solution, subconjunctival ABs etc

! one problem with demonstrating effectiveness of a prophylaxisstrategy is the power required to demonstrate statistical significance

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Cefuroxime v Cefazolin

! Cefuroxime for injection not available in Australia

! Cefazolin is

! a “first generation” Cephalosporin, used more for prophylaxis thantreatment

! Good Gram positive cover (Staphyococcus sp, not MRSA;Streptococcus sp)

! AC concentration after intra-cameral injection exceeds MIC forMRSA

Why not use intra-cameral antibiotics?

! Penicillin or Cephalosporin allergy

! Scepticism regarding elements of study

! high rate of endophthalmitis in control group

! disagreement over which is the “optimal” topical or intra-cameral agent

! Lack of commercially-available preparation

! Concerns about possible increased risks of

! TASS

! endothelial toxicity

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IFIS

Benign Prostatic Hyperplasia

! hyperplasia of stromal and epithelial prostate cells large discretenodules in periurethral prostate

! compresses urethral canal, interfering with flow of urine

! symptoms:

! storage: increasing frequency, nocturia, urgency, urgencyincontinence

! voiding: dribbling, hesitancy, intermittency, straining to void

! 50% of men by age 50, 75% by age 80, symptoms in 40-50% of these

Intra-operative Floppy Iris Syndrome (IFIS)

! characterised by

! flaccid iris which billows in response to ordinary intra-ocular fluidcurrents

! a propensity for floppy iris to prolapse through surgical incisions

! progressive intra-operative miosis despite standard procedures toprevent this

! classification: mild- iris billowing, moderate- iris billowing &intraoperative miosis, severe- iris billowing, miosis & iris prolapse

! more than doubles risk of serious complications**CM Bell et al. Association Between Tamsulosin and Serious Ophthalmic Adverse Events in Older Men Following Cataract Surgery. JAMA 2009; 301(19): 1991-1996.

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IFIS

! Associated with use of alpha-adrenergic antagonists especiallyTamsulosin (Flowmaxtra)

! a selective alpha blocker

! works by relaxing bladder and prostatic smooth muscle

! also relaxes the iris dilator by binding to its postsynaptic nerveendings

! ceasing Tamsulosin doesn’t alter risk and risk is not related toduration of use

IFIS Management - avoiding or minimising problems“fore-warned is fore-armed”

! Preoperative:

! pupil needs to be well dilated from the start; Atropine Sulfate 1% well in advance, 2-3 days prior to surgery

! Intraoperative: 

! incision construction for all wounds - anterior, a square, longer tunnel

! epi-shugarcaine (Joel Shugar) - BSS (9ml), lignocaine (3ml 4%), adrenaline (4ml 1:1000)

! high-viscosity OVDs (eg Healon5 - AMO, DisCoVisc - Alcon) create pressure on anterior surface of the iris andalong the puplillary margin (“viscomydriasis” and “viscodilation”)

! mechanical pupillary dilation - 4 to 5 iris retractors or disposible 5-0 polypropylene Mayyugin Ring (MST)

! low flow parameters - bottle height, vacuum rates (< 200 mmHg), low aspiration rate (< 26 mL/min) 

Corneal Decompensation

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Causes of post-operative corneal edema

! surgical trauma

! primary corneal endothelial disease

! chemical injury

! IOL syndromes

! contact with ocular tissues

! detachment of Descemet’s membrane

! trauma from retained foreign material

! postoperative glaucoma

! infammation

! membranous ingrowth, vitreous adgerence, Brown-McLean syndromeRF Steinert. Corneal Edema After Cataract Surgery. In RF Steinert (Ed). Cataract

Surgery . 2010

Causes of post-operative corneal edemaSurgical Trauma

! instruments

! IOL

! irrigating solutions

! ultrasonic vibrations

! nuclear fragments

! prior surgery

Causes of post-operative corneal edemaPrimary endothelial disease

! Fuch’s endothelial dystrophy

! reduced endothelial cell count (“coarsemosaic”)

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Management of post-operative corneal edema

! eliminate cause -

! treat inflammation, lower IOP

! remove tissue/IOL contact, reattach Descemet’s

! enhance surface dehydration - eg hypertonic saline

! manage pain - lubricants, SCL etc

! restore anatomy - keratoplasty

! DSEK/DSAEK/DLEK/DMEK/PK

RF Steinert. Corneal Edema After Cataract Surgery. In RF Steinert (Ed). Cataract Surgery. 2010

Post-operative corneal edemaPrevcntion

! identify the “at risk” patient

! Fuch’s dystrophy

! the “coarse” endothelial mosaic

! low flow

! dispersive OVD eg Viscoat (Alcon) & DisCoVisc (Alcon)

! reduce chatter (torsional ultrasound) and total energy

The Ruptured Capsule and the “Dropped” Nucleus

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Vitreous loss and its management

! Vitreous loss is inevitable

! 0.5% to 14.5% incidence

! higher incidence in less experienced surgeons and more complexcases

! Goals of surgery include

! avoiding complications

! managing complications to secure the BEST POSSIBLE outcomefor our patients

What increases the risk of encountering vitreous?(and dropping the ball?)

! dense brunescent cataracts

! pseudoexfoliation

! posterior polar cataracts and posterior lenticonus

! (very soft cataracts in younger patients)

! history of blunt trauma

! (Morgagnian cataract)

Dense Brunescent Cataracts

! increased vertical and horizontal size

! less epinucleus

! more ultrasound power and nuclear manipulation with longerprocedure

! often have difficulty disassembling nucleus

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PXF and Cataract Surgery

! two proven risk factors for vitreous loss are PXF and poordilation

! PXF associated with

! Poor dilation (very common in PXF)

! Zonular fragility ( risk of lens dislocation / zonular dialysis up to 10x)

! Posterior capsule rupture (up to 27% compared to 2% of controls*); PC is of normal thicknessin PXF but risk of rupture may be due to

! degenerate capsule

! excessive “stickiness” of the remaining cortical material and increased difficulty inirrigation and aspiration

* Goder GJ: Our experiences in planned extracapsular cataract extraction in the exfoliation syndrome. Acta Ophthalmol 184(Suppl):126–8,1988

What is Pseudo-exfoliation?

! an unidentified, fibrillar substance (PXM) is produced in high concentrations within oculartissues; EM studies suggest localized production by these cells and extracellularaccumulation & deposition of PXM

! prevalence varies with geography - 20–25% in Iceland and Finland, 5% in USA

! PXF is clinically visualized as white, flaky PXM deposits on intraocular tissues - sources ofthe PXF protein include

! lens epithelium

! trabecular meshwork, iris, ciliary processes

! conjunctiva

! systemic disorder - skin, aorta, brain, heart, and kidney contain PXM

Why does effective vitreous management matter?

! Sequelae of vitreous loss include:

! Cystoid macular edema

! Retinal detachment: up to 1% after uncomplicated cataract surgery, 6-8% after vitreous loss

! Persistent increase in IOP

! IOL dislocation or subluxation

! Choroidal detachment

! Endophthalmitis

! Suprachoroidal hemorrhage

! Corneal edema

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! But ...

! Vitreous is invisible in the AC under the operatingmicroscope

! Traction on anterior vitreous is dangerous

! proximity to strong, permanent vitreo-retinaladherence at vitreous base

! peripheral retina has approximately 1/100 the tensilestrength of posterior retina

! So visualising it and understanding its surgicalbehaviour would be helpful

! “this huge advance in the management of complicationscannot be overestimated” *

! Triamcinolone is “washed” to remove preservatives thatmay be toxic to endothelium

! when irrigated into anterior chamber it sticks to thevitreous matrix, but washes out of OVD or BSS

! like throwing a ‘‘sheet over a ghost’’ guiding vitreousremoval and providing a secure end-point for it’s removal

* Lisa Brothers Arbisser, Steve Charles, Michael Howcroft, Liliana Werner. “Management of Vitreous Loss and Dropped Nucleus During CataractSurgery.” Ophthalmol Clin N Am. 2006; 19: 495–506.

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Refractive Complications

Error in IOL Power Calculation

! anterior chamber depth (35%)

! predicted from preoperative parameters

! compressed vault height

! capsulorhexis size

! post-operative refraction (27%) - outcome parameter but mean SD of manual refraction ~0.4D (auto ~0.2D)

! axial length measurement (17%) - this error has shrunk dramatically with optical measurement (SD +/-0.03mm)

! pupil size (8%) - less of an issue with reducing spherical aberration

! keratometry

! IOL power

Norrby S. Sources of error in intraocular lens power calculation. J Cataract Refract Surg 2008; 34:368–376.

What is Femtosecond Laser (FSL)?

! FSL systems use ultrashort pulses of laser and produce corneal tissuecutting using a photodisruption process; energy parameters andpulse rates differ between systems

! high pulse energy and low pulse frequency

! low pulse energy and high pulse frequency

! FSLs create bubbles in cornea & other ocular tissues

! a flap (eg LASIK flap) can be created if multiple bubbles are madein a plane parallel to surface of the cornea

! tissue can be removed if multiple layers are createdLubatschowski H. Overview of commercially available femtosecond lasers in refractive surgery. J Refract Surg.2008;24:S102–S107

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Why the drive to femto-assisted cataract surgery?,or “why are 4+ companies pushing this technology”

! ~170,000 cataract procedures in Australia annually (3.3 million in theUS in 2010, 18.9 million worldwide); this is growing

! Alcon Inc posted 2010 EBIT of US$2.6 billion; surgical sales areresponsible for ~45% of total revenue (>US$7 billion)

! FSL have been used in LASIK for 10 years, now worldwide themajority of LASIK flaps are cut with FSL

Why the drive to femto-assisted cataract surgery?,or “what are the supposed benefits for patients”

! Improvements in safety

! reduction in anterior capsule tears

! reduction in phaco power

! better wound construction

! Improvement in outcomes

! better effective lens position (ELP)

! less surgically-induced astigmatism (SIA)

! more predictable astigmatism management with LRIs

Capsulotomy / “Laser-incised capsulorhexis”

! the perfect capsulotomy is:! central! not too big (ie not enough capsule overlap of the optic)

! tilt

! decentration

! PCO

! not too small (too small means < 5.5mm)

! anterior capsule fibrosis and phimosis

! (hypermetropic shift)

Ravalico G, Tognetto D, Palomba M, et al. Capsulorhexis size and posterior capsule opacification . J Cataract Refract Surg 1996; 22:98–103.Walkow T, Anders N, Pham DT, Wollensak J. Causes of severe decentration and subluxation of intraocular lenses . Graefes Arch Clin Exp Ophthalmol 1998; 236:9–12.Wallace RB 3rd. Capsulotomy diameter mark . J Cataract Refract Surg 2003; 29:1866 – 1868.Sanders DR, Higginbotham RW, Opatowsky IE, Confino J. Hyperopic shift in refraction associated with implantation of the single-piece Collamer intra- ocular lens . JCataract Refract Surg 2006; 32:2110–2112.

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Capsulotomy:What is the evidence that this matters to refractive outcome?

! capsulorhexis size is recognized as an important determinant of post-operative anterior chamber depth

! small rhexis is more likely to lead to greater ACD and hyperopic shift

! ELP (effective lens position)

! concept that represents the IOL A constant and “surgeon factors”

! thought to be the single biggest error variable in post-operative refraction

! FSL can precisely size and centre the capsulotomy - will this improverefractive outcomes?

Cekic O, Batman C. The relationship between capsulorhexis size and anterior chamber depth relation. Ophthalmic Surg Lasers 1999; 30:185–190.Norrby S. Sources of error in intraocular lens power calculation. J Cataract Refract Surg 2008; 34:368–376.

Relaxing incisions

! advocates of LRIs for astigmatic control feel they are under-utilised

! 140,000 cataract operations performed in Australia in FY10, 2,500 LRIs; this has stayed static even afterintroduction of toric IOLs

! FSL may make them more consistent and their placement moreaccurate

! whether this will make them more effective is unclear

! toric IOLs are still likely to be the preferred method of managing astigmatism >1.5D

! (some US surgeons have advocated using FSL to “mark” axis of toric IOL with a small LRI )

What’s the take-home message?

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! cataract surgery is a combination of sequential critical steps

! errors or problems can occur at each step

! the final outcome is dependent on contingency planning and gooddecision making

! moving from 96% to 98% to 99% requires relentless attention to detail

! improvements in the best outcome will be industry driven, improvingthe worst outcomes must be clinician-driven