CATARACT AND REFRACTIVE SURGERY PEARLS
From the 2007 Annual Meeting, New Dimensions in Ophthalmology, presented by the Washington Academy of Eye
Physicians and Surgeons, Seattle, WA
Mark Packer, MD, Clinical Associate Professor of Ophthalmology, Oregon Health and Sciences University School
of Medicine, Portland
| REFRACTIVE CATARACT SURGERY
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| Market projections: growth area for ophthalmologists; over next decade, most sales of intraocular lenses
(IOLs) predicted to be for correction of presbyopia; most will be multifocal, accommodative, or phakic
refractive lenses; in speaker’s practice, most IOLs implanted are monofocal, but multifocal and accommodative
IOLs, refractive lens exchange, and phakic refractive IOLs account for majority of revenues
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| Integrating refractive cataract surgery with presbyopia correction into one’s practice
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 | Patient education: discuss potential for spectacle independence; types of IOLs available; negative as well
as positive features of each
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| Drawbacks of multifocal IOLs: halos around lights at night; contrast sensitivity diminishes over time,
but adjustment may be difficult; patients must have realistic expectations; according to Food and
Drug Administration (FDA) data, 30% of patients report moderate to severe halos with most commonly
used lens (ReSTOR), compared to 3% of control patients; however, same data show that 80%
of patients never need spectacles with ReSTOR lens
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| Accommodative lenses (Crystalens [made by Eyeonics]): for people who cannot tolerate halos, even
temporarily; however, spectacles may be required for near vision; distance vision better than that
achieved with monofocal lenses, despite 1 in 4 chance that patient will need glasses
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| Mixed-technology lenses: improve spectacle independence; provide good distance vision; lengthen
neuroadaptation time
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| Differences among lenses: accommodative—ReSTOR provides better close-up vision; ReZoom provides
better distance vision; range of accommodation unpredictable (varies among patients);
multifocal—produce halo
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| Surgical parameters: accommodative lens requires intact capsular bag; pristine capsule with round
centered rexhis also important; multifocal lenses can go in bag or sulcus; “perfect, pristine surgery”
not as critical as with accommodative lens
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| Approach to residual refractive error after presbyopia correction: enhance vision with laser-assisted in
situ keratomileusis [LASIK] or piggyback IOL
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| Speaker’s results with standard spherical monofocal IOLs: 92% of patients come within +0.5 diopters
(D) of targeted refraction; however, with multifocal IOLs, 100% of patients come within +0.5 D of
targeted refraction; results less predictable (85%) with accommodative IOL
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| Predictors of poorer outcomes with accommodative IOLs: retrospective case-control study of 83 consecutive
eyes that underwent refractive lens exchange with accommodative IOLs; most problems experienced
by eyes in low hyperopic range (undercorrection); however, after eliminating 9 eyes with
known risk factors from analysis (eg, previous refractive surgery or complications), remaining 74
eyes in 41 patients varied widely in axial length; uncorrected vision after surgery ranged from 20/15
to 20/70 (J1-J16); in people unhappy with vision and requesting enhancement, mean uncorrected vision
20/60; patients with planned piggyback surgery had very short eyes; axial length also short in
10 people undergoing unplanned piggyback procedures; axial length sole predictive factor for piggyback
IOL or enhancement; after additional procedure, all patients had uncorrected vision of 20/40 or
better (mean improved from 20/60 to almost 20/20); demonstrates that piggyback IOL can be used
after implantation of accommodative lens to correct residual refractive error; however, LASIK better
choice for correcting residual astigmatism
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| New developments: Tecnis ZM 001 multifocal lens (made by Advanced Medical Optics)—already available
outside United States and in clinical trials in United States; in German study, patients did well in bright
light, with no or best distance correction; patients also did well in dim light because of full-optic diffractive
lens design; Synchrony (made by Visiogen)—dual-optic accommodative lens; front optic consists of
32-D lens that moves within eye; rear optic variable minus-powered lens; together, they provide resting
emmetropia and >3 D of accommodation; injector designed by toy manufacturer; displaces and folds optics
before squeezing them through incision; lens bag remains clear due to ongoing aqueous circulation;
minimal fibrosis due to minimal contact between silicone and capsule
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| NEXT-GENERATION IOL TECHNOLOGY
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| Background: quality of vision achieved with current IOLs similar to that in younger emmetropes; cornea
does not change much with age; lens sustains most age-related changes; increasing spherical aberration
responsible for most age-related loss of vision quality
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| Aspheric lenses: Bausch & Lomb Advanced Optic—focuses incoming light to single point; Alcon AcrySof
IQ—wavefront lens with negative spherical aberration; works with cornea to nearly eliminate spherical
aberration; AMO Tecnis—designed to balance average spherical aberration of human cornea (+0.27
µ; so lens has aberration of -0.27 µ); confers dim-light contrast sensitivity similar to that of bright-light
sensitivity provided by spherical lens; peak contrast sensitivity exceeds that of healthy normal subjects
in their 20s; nearly 24 studies have shown reduced or eliminated spherical aberration and improved
functional vision with Tecnis; Center for Medicare and Medicaid Services has designated aspheric
lenses new-technology IOLs
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| Customizing IOL selection: accomplished through preoperative measurement of corneal spherical aberration
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| Effect of corneal surgical incisions: aberration introduced (mean 0.03 µ); range broad and unpredictable
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| Determining target degree of aberration: corneal spherical aberration does not determine vision quality;
in phakic individuals, spherical aberration changes throughout life; presents “moving target” when
choosing IOLs; in tests in vision simulator, zero aberration yielded best results
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| Choosing best IOL: use preoperative corneal spherical aberration measurement to find IOL that provides
total wavefront aberration closest to zero
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| Decentration: most IOLs today range from 0.1 to 0.3 mm off visual axis (not enough to affect visual
quality); significant decentration occurs in only 6 of 1000 eyes
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| Depth of focus: similar with spherical and aspherical lenses
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| Lenses for patients who have undergone previous keratorefractive surgery: most difficult task achieving
emmetropia; patients who have undergone myopic procedures usually do better with negatively aspheric
lens; those with history of hyperopic surgery do better with spherical lens
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| MANAGEMENT OF ASTIGMATISM
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| Surgery: limbal relaxing incisions common; results of on-axis corneal incisions less predictable; arcuate
keratotomy even less predictable, may flip axis of astigmatism
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| Toric IOLs: Staar IOL—rotational instability not as problematic as many feared; stability improves when
inserted upside down (also associated with better correction of astigmatism); AcrySof—made by Alcon;
expected to be very rotationally stable
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| Measuring surgically induced astigmatism by vector analysis: can be done with special programs, or with
calculators found on Staar and Alcon Web sites
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| Limbal relaxing incisions: corneal depth critical variable; less accurate and predictable than LASIK,
but reduces astigmatism to reasonable level so patient can see well enough and be less dependent on
spectacles; speaker uses topography to determine location of steep axis; applies ultrasonic pachymetry
at 12-mm zone; uses nomogram based on patient’s age and degree of astigmatism (Nichamin nomogram
available at http://mastel.com/pdf/napa.pdf), which can be refined based on own results; makes two
40º arcs of 27º (mark axis at 6 and 12 o’clock with patient awake, sitting up, and fixating on distant
target; use fixation ring); diamond blade recommended for incision; speaker uses fully adjustable
blade, guarded on both sides
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| Economic concerns: Medicare has reduced payment for cataract surgery; many patients unaware that
they have corneal astigmatism; explain that this procedure will make them independent of glasses for
distance vision, but not covered by Medicare; measure outcomes to demonstrate value of surgery for
patient
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Suggested Reading
Fine IH et al: Profile of clear corneal cataract incisions demonstrated by ocular coherence tomography. J
Cataract Refract Surg 33:94, 2007; Franchini A: Comparative assessment of contrast with spherical and aspherical
intraocular lenses. J Cataract Refract Surg 32:1307, 2006; Kasper Tet al: Visual performance of
aspherical and spherical intraocular lenses: intraindividual comparison of visual acuity, contrast sensitivity,
and higher-order aberrations. J Cataract Refract Surg 32:2022, 2006; Luttrull JK, Dougherty PJ:
Acrylic multifocal IOLs. J Refract Surg 23:329, 2007; Mester U et al: Functional outcomes after implantation
of Tecnis ZM900 and Array SA40 multifocal intraocular lenses. J Cataract Refract Surg 33:1033, 2007;
Nichamin LD: Astigmatism control. Ophthalmol Clin North Am 19:485, 2006; Packer M et al: Aberrations
after intraocular lens implantation. J Cataract Refract Surg 32:184, 2006; Packer M et al: Contrast sensitivity
and measuring cataract outcomes. Ophthalmol Clin North Am 19:521, 2006; Packer M et al: Refractive
lens surgery. Ophthalmol Clin North Am 19:77, 2006; Packer M et al: Wavefront technology in cataract surgery.
Curr Opin Ophthalmol 15:56, 2004; Packer M: The age of refractive lens surgery. Curr Opin Ophthalmol
15:56, 2004; Pandita D et al: Contrast sensitivity and glare disability after implantation of AcrySof IQ
Natural aspherical intraocular lens: prospective randomized masked clinical trial. J Cataract Refract Surg
33:603, 2007; Pepose JS et al: Visual performance of patients with bilateral vs combination Crystalens,
ReZoom, and ReSTOR intraocular lens implants. Am J Ophthalmol July 23, 2007 [Epub ahead of print];
Vingolo EM et al: Visual acuity and contrast sensitivity: AcrySof ReSTOR apodized diffractive versus
AcrySof SA60AT monofocal intraocular lenses. J Cataract Refract Surg 33:1244, 2007; Zeng M et al: Aberration
and contrast sensitivity comparison of aspherical and monofocal and multifocal intraocular lens
eyes. Clin Experiment Ophthalmol 35:355, 2007.
Educational Objectives
| The goals of this program are to improve refractive cataract surgery and astigmatism management, and to introduce
new developments in intraocular lens (IOL) technology. After hearing and assimilating this program, the clinician
will be better able to:
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| 1. Identify the main drawback of multifocal IOLs.
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| 2. Describe the difference between accommodative and multifocal IOLs in terms of visual quality and surgical
procedures.
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| 3. Explain the role of lenticular spherical aberration in age-related vision changes and in the design of aspherical
IOLs.
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| 4. Discuss methods for choosing the best IOL for each patient.
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| 5. Address some of the financial issues associated with toric IOLs.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty members to
disclose relevant financial relationships within the past 12 months that might create any personal conflicts
of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality
in health care and not a proprietary business or commercial interest. For this program, the following has
been disclosed: Dr. Packer is a consultant for Advanced Medical Optics, Advanced Vision Science,
Bausch & Lomb, Carl Zeiss Meditec, Carl Zeiss Surgical, Celgene, Ethicon, Gerson Lehrman Group,
iScience Surgical, Johnson & Johnson Vision Care, Leerink Swann & Company, Medtronic Xomed, Visiogen,
and VisionCare. He has received travel and research grants or honoraria from Alcon Laboratories,
Endo Optiks, eyeonics, and Staar Surgical. Dr. Packer also has stock options in WaveTec Vision Systems.
Acknowledgements
Dr. Packer spoke at the 2007 Annual Meeting, New Dimensions in Ophthalmology, held March 29-30, 2007, in
Seattle, WA, and sponsored by the Washington Academy of Eye Physicians and Surgeons. The Audio-Digest
Foundation thanks the speaker and the sponsor for their cooperation in the production of this program.
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