1 The Cataract Surgery Nightmare: When It Doesn’t Go To Plan Dr Michael Forrest Northside Eye Specialists, Nundah Senior 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 large change 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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Is 99% good enough? Or 99.9%%? Or 99.99%2 Acute Post-Operative Bacterial Endophthalmitis Endophthalmitis! arguably the most-feared complication of cataract surgery! can result in blindness
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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
! 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
! 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)
! 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
! 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