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Premier IOL choices- Earlier cataract surgery vs Femtosecond laser cataract surgery
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Premier IOL choices Technique & Decision Makingor earlier cataract surgery
or do we really need femtosec laser cataract surgery
Dr. Inderjit Singh
FRCS(E)., FRCOphth., FRANZCO
Chatswood , Sydney
Aim of modern cataract Surgery Royal College of Ophthalmologists
Restoration of vision Achievement of desired refractive
outcomeImprovement QOLEnsuring safety and satisfactionA VA is not mentionedMeticulous pre-op;intra-op;post op mng
Earlier Cataract Operations (1)
Outcomes in small incision is more predictable Glasses free vision-Toric and Multifocal IOLs Safer operation because of smaller incisions Meet the visual demands that patient expects Short recovery period
Earlier Cataract Operations (2)
Surgery should be performed for symptoms rather than a number on a vision chart– Influenced by a variety of cataracts
Earlier Cataract Operations (3)
Allow patients to minimise glasses wear Have the surgery at an age when you are still healthy
and active Improved vision, via cataract surgery, minimises falls.
Fractured hip aged 75, 40% survive one year. Contralateral hip fracture, in such a patient
Earlier Cataract Operations (4)
Minimize future AAC glaucoma Improves glare and night drivingUp to 97% of patients are achieving
UDVA/CDVA of 6/4
Visual Function Test- VF7
Reading signs – traffic,street,storeSeeing steps,stairs,or curbsWatching TVNight drivingReading small printDoing fine handiworkCooking
The Unhappy Patient
Ocular Co-morbidities Refractive surprises Astigmatism Amblyopia
FOCUS Autumn 2010Pt. Expectations
The success of refractive cataract surgery depends on achieving a predictable refractive outcome for defocus (spherical equivalent) and astigmatism. Refractive surprises can seriously compromise patient
satisfaction and also give rise to potential problems of anisometropia, dominance switch in which the dominant eye ends up with the weaker uncorrected vision and, above all, give rise a sense of failure in patients expecting good
uncorrected visual acuity.
FOCUS – Autumn 2010Ocular comorbidities
Small hyperopic eyes, large myopic eyes, eyes with very steep or flat corneas, shallow anterior chamber depths, history of refractive surgery, vitrectomy, corneal ectasia, peripheral corneal melt syndromes and contact lens use (when measured without an adequate contact lens holiday) are at significant risk of refractive surprises. It is important to warn these patients of the increased risk of refractive surprise as part of the informed consent process and prepare the patients for a second stage enhancement procedure
Refractive Surprise
Refractive Cataract Surgery
Restore transparency of ocular media +correct any refractive aberrations of the eye (ametropia,astigmatism)
Reduce spec dependence QOL and economic benefits
Refractive Surprise
Anisometropia Dominance switch Sense of failure in pts
expecting good uncorrected va
Refractive Surprise - Sources of ErrorNorrby,S. JCRS 34/3 March 2008
IOL power calculations- SRKT, HofferQ, Haigis,HolladayII, Post op Effective Lens position(36%) ( Optimising IOL constant
most important factor,Anstodemon,JCRS Jan 2011) Error in post op refraction(27%) AXL Measurements(17%) Pupil Size(8%) – only if there is spherical aberration Keratometry(10%)- ant curvature with keratometer,topographers;post
curvature IOL Power –very small variability,(desired outcome deviation =max
0.18D) Other Sources of error- corneal thickness,post surface
asphericity,higher order,chromatic aberrations,change in corneal power (Norrby,S JCRS 34/3 March 2008)
What about Astigmatism Pre-existing corneal astig –TORIC IOL Surgeon induced astig – astigmatic neutral
incision. Nailing +/- 0.50 D for both sphere
and cylinder is important
+1.00-2.00x90(SE=0) +0.25-0.50x90(SE=0)
Ferrer-Blasco T,Montés-Micó R,Peixoto-de-Matos SC,González-Méijome JM,Cerviño A.Prevalence of corneal astigmatism before cataract surgery.J Cataract Refract Surg.2009;35(1):70-75. N =
4540 eyes.
87% of cataract surgery patients have preoperative astigmatism
64% of patients fall within 0.50 to 1.2536% of patients having greater than 1.26 D
ASTIGMATISM (contd)
16% of all eyes had astig of 1.5D or more 46.8% WTR(minus cyl @180) , 34.3% ATR Temp clear corneal incision will reduce
astig in 34% of pts but worsen for 47% Corneal astig did not increase with age Correlations -AXL,Ks,ACD,WTW-normal
and abnormal eyes – effect on effective IOL position
TORIC IOLs- New Standard of careWolffsohn,JCRS,Effect of uncorrected astigmatism on
vision March 2011
Modest amounts of astigmatism can have major effect on vision
Effect independence – night,rain driving Quality of life, well being – reading speed Higher risks of falls Worse with WTR
1.Eliminate Surgeon Induced Astigmatism - Results of Astigmatism Studies Masket, MD
Surgeon Factor
The surgically induced astigmatic factor is usually in the range between 0.25 and 0.50 D when a 2.2- to 2.4-mm incision is used. Ideally, a surgeon should review the outcomes of one’s previous 20 or more cases, comparing preoperative keratometric measurements with postoperative readings. Routinely reexamining one’s surgically induced astigmatic factor to monitor for any changes can also be beneficial.
Astigmatism
aim for both spherical and astigmatic outcomes of ±0.5 D to avoid symptoms of ghosting and shadows.
A patient with >=0.75 D of regular corneal astigmatism and who desires spectacle independence for distance vision may be considered for a toric IOL. Evidence supports the use of toric IOLs even in patients with low levels of astigmatism
Statham M, Apel A, Stephensen D. Comparison of the AcrySof SA60 spherical intraocular lens and the AcrySof Toric SN60T3 intraocular lens outcomes in patients with low amounts of corneal astigmatism. Clin Experiment Ophthalmol. 2009;37:775–779
Wound assisted Un-enlarged 2.2mm Incision
K values and corneal topography centred on visual axis
nasaltemporal
Toric IOLSAlcon,
Zeiss- larger corrections
SN60 T2 = 0.5 D correction
SN60 T2 = 0.5 D – 1.0 D correction
Toric IOLs
2.2mm incision at mark5-5.5mm CCCCohesive viscoelastic (provisc) for easy and
complete removal from behind IOLPrecise alighnment using I/A tip start 10-20 shy of markings
Other Factors affecting postop astig-IOL Tilt and Shift
Small rhexis- hyperopic shift Post capsule debris (viscoelastic) and
fibrotic bands-myopic shift and cyl Irregular rhexis One loop in bag only
Toric IOLS(140 eyes )
Stable IOL in the bagAfter 1yr.- 100% within 10*
96% within 5*Markings can be 5* off> 10* from axis reduces effect by 1/3> 30* from axis causes increased astig
Toric IOLs-Pre Op Prep
Accurate Ks and AxlContact Lens wearers - 1-3 weeksMeasure undisturbed corneasGet pt to blink often whilst measuring Ks
Toric IOLs Pre Op
Mark 180 meridian steep meridian and incision site at Slit lamp.
Keep limbus dry Use thin fine mark –
thick pen = upto 10degrees
Toric markingsGraether Toric Marker ASICO
Visual axis, CCC markings visual axis David Jory 8 marker
Repeatable CCC
REPEATABLE CCC
REPEATABLE CCC
Scanning electron micrographsof the excised capsule disk edge produced by manualcapsulorhexisA) and laser capsulotomy(B). White arrows in B point to the microgrooves produced by the laserNJ Friedman -J Cataract Refract Surg. 2011 Jul;37
Stable Effective IOL positiondepends on
100 eyes Selected at random CCC measured at slit lamp Range of CCC size 5.0- 5.3 mm All covered optic CCC with bent cystotome(15c)
CCC covering optic edge
Toric IOLS(140 eyes )
Stable IOL in the bagAfter 1yr.- 100% within 10*
96% within 5*Markings can be 5* off> 10* from axis reduces effect by 1/3> 30* from axis causes increased astig
Refractive cataract surgery
1.astigmatism can be corrected2.repeatable sized CCC = stable effective
lens position3.small astig neutral incision1 + 2 + 3 = predictable stable refrective
outcome.BUT WHAT ABOUT NEAR VISION ?
MULTIFOCAL IOLs
HAPPY PATIENT
Problem1. Astigmatism
2. Astigmatism - prexisting
3. Glasses free vision
4. Rapid visual /life style recovery
5. Refractive surprise
6. Changing refraction
7. PCO
8. Inflammatory consequences-CME.DME
9. Comorbidities
Solution
1. 2.2mm astig neutral incision
2. Toric IOL
3. Multifocal /toric IOL
4. Polite low energy quick phaco
5. Accurate biometry.optimise A
6. CCC over optic – stable IOL
7. Polish post capsule
8. Pre-op NSAIDS,polite low energy phaco (Ozil phaco)
9. Assessment (OCT) +counselling
End Points forSuccessful Cataract Surgery
=quality of visionHigh contrast va maintained long term
Aspheric IOL Residual refraction defecit = 0.50 for both
SE and astig – Aspheric Toric and Multifocal Toric