REFRACTIVE SURGERY UPDATE
From the Cataract and Refractive Surgery Congress, presented by the Bascom Palmer Eye Institute and sponsored by the
University of Miami Miller School of Medicine, Miami, FL
| REFINING REFRACTIVE OUTCOMES IN CATARACT SURGERY —Jill Rodila, MD, Assistant Professor of
Clinical Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL
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| Considerations in “refractive” cataract surgery: often suggested that patients be ≈0.25 D from plano and have
<0.50 D of cylinder to be satisfied without spectacles; precision especially critical when patients demand and pay for
certain outcome (correction of, eg, myopia, hyperopia, astigmatism, presbyopia); patient will be dissatisfied with significant
residual refractive error; postoperative correction of residual refractive error may incur costs in time and
money to patient and physician; also consider risk for complications associated with additional procedure
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 | Best way to achieve emmetropia: choose best intraocular lens (IOL) power
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| Calculating best IOL power: measure corneal power, eye’s axial length, and lens position
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| Measuring corneal power: instruments measure radius of curvature; this number then converted to diopters of corneal
power; with most keratometers in United States, default corneal index 1.3375
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| Axial length: only value that can be measured directly
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| Lens position: possibly most important factor in determining IOL power; accuracy of anterior chamber depth measurement
considered major limiting factor in accuracy of IOL power calculation; IOL position cannot be measured
before surgery (current formulas rely on anterior chamber depth and axial length)
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| Refining outcomes: meticulous biometry and data entry; use latest-generation formulas; optimize lens constants;
address degree of astigmatism surgically induced
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| Observing for error: begins with initial examination; treat irregular ocular surface caused by dry eye before biometry;
other corneal irregularities harder to correct (counsel patient about expectations); tips for assessing accuracy
of keratometry—have second technician validate measurements in atypical eyes; also obtain second measurement
if average corneal curvature (K) difference between eyes >1 D; obtain another reading if fixation poor, or if
degree of astigmatism disagrees with refraction
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| Measuring axial length: done with immersion A-scan (uses ultrasonography; more accurate) or IOL Master (uses infrared
light); assessing accuracy of immersion—have second technician repeat measurements in atypical eyes if axial
length <22 mm or >25 mm; perform concurrent B-scan if eye has posterior staphyloma; consider repeating
measurement if difference in axial length between eyes >0.3 mm and does not correlate with refraction (found in
24% of patients in one recent study); make sure technician changes velocity for pseudophakic eye or one containing
silicone oil; error of 0.1 mm equates to error of 0.28 D; assessing accuracy of IOL Master scan—signal-to-noise ratio
(SNR) >2 suggests reliable reading; high SNR less likely with dense posterior subcapsular cataracts or poor preoperative
visual acuity; if SNR <2, IOL Master may exaggerate axial length and lead to hyperopia; some
investigators recommend obtaining A-scan if SNR <5; accuracy-limiting factors include inability to fixate and defects
that impede light transmission (eg, corneal opacity)
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| Personalizing IOL formulas: biometry and surgical method should be consistent and reproducible; current formulas all
produce good results; latest-generation formulas (Holladay 2, Haigis, and Olsen) preferred, especially for atypical
eyes; accuracy enhanced by using anterior chamber depth and >2 variables to predict IOL position; choose IOL
power for both eyes, then analyze calculated IOL power between them to check for gross errors; also calculate surgically
induced astigmatism; correct if >0.5 to 0.75 D
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| UPDATE ON SURFACE ABLATION —Kendall E. Donaldson, MD, MS, Associate Professor of Ophthalmology,
Bascom Palmer Eye Institute, University of Miami Miller School of Medicine
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| Proportion of average refractive surgeon’s practice devoted to surface ablation: more than tripled over
last few years, due largely to “ectasia awareness”
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| Risk for ectasia: 1 in 11,000; according to 2007 survey, ≈19% of practitioners have had one case; risk factors include
thin corneas, inferior steepening, and young age; topographic red flags—pachymetry (thin corneas; inferior thinning
on corneal topography mapping); posterior float >0.05; K reading >45.5; may also develop several years after
surgery in patient with no apparent risk factors
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| Epi-laser in situ keratomileusis (Epi-LASIK): safest available form of refractive surgery; combines advantages
of LASIK and photorefractive keratectomy (PRK); cleaves between Bowman’s layer and basal laminal epithelium;
smooth cleavage plane reduces risk for cytokine release from epithelial cells
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| Candidates: anyone with thin or steep corneas, dry eye, or irregular topography; anyone with specific occupational
demands or who is concerned about flap and desires safest possible procedure
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| LASIK and surface ablation compared
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| LASIK: advantages—rapid visual recovery; comfort; convenient follow-up; excellent visual outcomes;
disadvantages—flap complications; risk for epithelial ingrowth; striae; diffuse lamellar keratitis (DLK); flap dislocations;
infection; ectasia; femtosecond laser has decreased incidence of flap complications, but other disadvantages remain
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| Epi-LASIK: advantages—decreased risk for dry eye; ability to treat patients with thinner corneas; reduced risk for
ectasia; avoidance of flap complications; safe for patients with steep corneas; good for people with tight brows;
eliminates higher-order aberrations caused by flap creation; good for people with corneal surface problems;
disadvantages—delayed recovery (inconvenient; requires 1-wk absence from work or school); more discomfort;
more anxiety during recovery for patient (and surgeon); possible risk for haze formation
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| Surface ablation vs LASIK: better optics, better mechanics, comparable visual outcomes, and better stability at 4
yr; decreased risk for higher-order aberrations associated with flap
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| Epi-LASIK vs laser epithelial keratomileusis (LASEK): epi-LASIK produces clean separation between layers, with
little cytokine release; alcohol used in LASEK disrupts cells, with high cytokine release
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| Military study: involved >32,000 eyes; no difference in visual outcomes associated with LASIK or surface ablation;
major obstacles—discomfort; rate of recovery; mean epithelial healing time 4.9 days (epi-LASIK); minimal
haze formation; 92% of patients had 20/25 vision or better by 3 mo
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| Mitomycin C: prophylactic use recommended for all eyes >-4.00 D; speaker uses 0.02% concentration
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| Advanced surface ablation: recommendations include application of chilled balanced salt solution (BSS) and frozen
sponges; use of continuous-wear contact lenses; role of oral steroids questionable
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| Epithelial flap: whether to save or not controversial; advantages of discarding flap include less pain, faster visual
recovery, faster epithelial regeneration, and no increase in haze
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| Speaker’s outcomes with surface ablation: 80 eyes done over past 2 yr; 3 enhancements; 60% of patients had 20/40
or better visual acuity by day 1, increasing to 80% by day 5, 92% by month 1, and 98% by month 3; discomfort
greatest on days 2 and 3; by day 5—75% of patients return to work; 65% feel able to drive; all would recommend
to friend by month 6
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| Sub-Bowman’s keratomileusis (SBK): thin-flap (90-µ) LASIK; associated with decreased incidence of dry eye;
faster recovery rate than PRK and lower risk for ectasia; however, thin flap may raise risk for striae, and may be
harder to work with than larger flap
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| MANAGING THE UNHAPPY REFRACTIVE SURGERY PATIENT —Carol L. Karp, MD, Associate Professor of
Clinical Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine
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| Issues to consider: patients have high expectations; usually pay out-of-pocket; want “perfection in their correction”
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| Causes of patient disappointment: unrealistic expectations of surgery; perfectionism; genuine surgical error
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| Preventing unrealistic expectations: have patient view chart at 20/40 to establish idea of outcomes without glasses;
specifically warn that 20/20 without correction not guaranteed; refuse to operate if patient expects and/or requires
20/20 vision without glasses; advise of risks (infection and inflammation leading to vision loss [rare] if severe
enough; dry eye; glare, halo [especially with multifocal lenses]); determine patient’s profession and interests
to assess his or her idea of optimal vision (eg, patients who drive at night may not be best candidates); ask patients
what they hope to derive from procedure
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| Rapport with patient: greatest aid in overcoming any subsequent problem; establish with careful preoperative discussion;
speaker calls all patients after surgery to learn how they are doing, answer questions, and provide reassurance;
handling major problems—spend time with patient; show concern through verbal and nonverbal
communication; instruct staff to expedite waiting time and provide “VIP treatment”; express concern and/or regret;
allow ample opportunity for questions; sit, do not rush through visit, look patient in eye; if remedy available,
describe it; if no remedy available, inform patient; discuss major problems with risk management staff;
document all conversations and risk factors
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| Preventing medical errors: recheck names with birthdays; always examine patient, answer questions before procedure;
recheck that entered treatment is correct; have patient state procedure and proper site
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| THE USE OF MITOMYCIN C IN REFRACTIVE SURGERY —Sonia H. Yoo, MD, Associate Professor of Clinical
Ophthalmology, Bascom-Palmer Eye Institute, University of Miami Miller School of Medicine
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| Background on mitomycin C (MMC): modulates corneal wound healing after excimer laser surface ablation;
used to prevent or minimize postablation haze; cross-linking properties enable it to bind to DNA and prevent fibrosis;
used after surgery for neoplasia, pterygia, or glaucoma; applications related to refractive surgery—
recurrent haze after surface ablation; LASIK flap complications; primary prevention of haze after surface ablation
for high myopia or after radial keratotomy or penetrating keratoplasty (PKP)
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| Treating pterygia: recommended dose, 0.01% to 0.04% MMC for ≤3 min; topical use may prevent recurrence
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| Complications: may be serious; include corneal-scleral melt, infectious scleritis, cataract, uveitis, secondary glaucoma,
and blebs; always consider long-term effects
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| Procedure: Epstein—obtain informed consent from high-risk patients (refractive error >-6 D, ablations >75 µ or
>18%); apply 0.02% MMC to stromal bed with saturated corneal light shield for 12 sec; irrigate with ≥30 mL BSS;
adjust nomogram to 8% to 15% of spherical component; Krueger—apply 0.002% MMC for 45 to 120 sec, depending
on refractive error (some haze detected in highest myopes at 1-2 yr); in one study, shorter applications associated
with less haze prevention in high myopes
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| Effect on corneal endothelium: depends on duration and concentration
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| Use in patients undergoing PRK after PKP: no haze; no significant decrease in endothelial cells at 1 yr
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| Case 1: patient underwent phototherapeutic keratectomy (PTK) with MMC to treat haze from PRK; haze recurred;
complications of MMC rarely reported after corneal procedures; reapplication of MMC “relatively safe,” but may
diminish endothelial cell count over time; patient underwent flap creation and amputation (encompassed haze) to
depth of 150 µ, followed by hyperopic PRK and application of MMC 0.2 mg/mL for 20 sec; patient took vitamin C
before and after surgery; completely reepithelialized at 1 wk; best corrected vision 20/25 at 1 mo; uncorrected vision
20/50 at 3 mo, with best corrected vision still 20/25
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| Case 2: patient complained of blurred uncorrectable vision after LASIK (LASIK enhancement in both eyes); patient
exhibited “monster” epithelial ingrowth with flap melt, irregular astigmatism, and poor uncorrected vision; treated
with flap amputation, MMC 0.2 mg/mL for 2 min; PTK to 15 µ on stromal bed; bandage contact lens; patient had
slight residual haze but did well otherwise; uncorrected vision currently 20/30
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| Summary: speaker uses prophylactic MMC for high-risk surface ablation (>-5 D); MMC dose, 0.02% (30 sec for
80-100 µ; 60 sec for 100-120 µ; 120 sec for >120 µ); longer duration also recommended for recurrent haze after
surface ablation, LASIK flap complications, post-RK, and PKP; adjust nomogram slightly for age and ablation
depth
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| CRYSTALENS AND YAG: FRIENDS OR MORTAL ENEMIES ?—David A. Goldman, MD, Assistant Professor of
Clinical Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine
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| Crystalens: specialized monofocal lens built on haptics; increased accommodative amplitude thought to result from
vaulting from posterior to anterior position of lens within eye; implantation requires intact posterior capsule; some reports
of asymmetric vaulting (“Z syndrome”) with 4.5-mm model; fewer reports with newer 5-mm model; many ophthalmologists
concerned about effect of yttrium aluminum garnet (YAG) laser capsulotomy on accommodative range
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| Review of speaker’s last 10 patients: all seen ≥6 mo after surgery; no decrease in uncorrected distant visual acuity
noted in any patient; 2 patients dropped one line of near vision, but 2 others gained one line; all patients felt vision
improved after treatment; none reported decrease in near vision (including those who had dropped one line)
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| Conclusion: YAG capsulotomy safe for patients with Crystalens; make sure opening smaller than central optic; rule
out other causes of decreased vision (eg, macular edema) first; avoid pitting of lens during surgery
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Suggested Reading
Jardim D et al: Asymmetric vault of an accommodating intraocular lens. J Cataract Refract Surg 32:347, 2006;
McCormick GJ et al: Higher-order aberrations in eyes with irregular corneas after laser refractive surgery. Ophthalmology
112:1699, 2005; Netto MV et al: Wound healing in the cornea: a review of refractive surgery complications
and new prospects for therapy. Cornea 24:509, 2005; Netto MV et al: Corneal haze following PRK with
mitomycin C as a retreatment versus prophylactic use in the contralateral eye. J Refract Surg 23:96, 2007; Pager
CK: Randomised controlled trial of preoperative information to improve satisfaction with cataract surgery. Br J Ophthalmol
89:10, 2005; Pallikaris IG et al: Epi-LASIK: preliminary clinical results of an alternative surface ablation
procedure. J Cataract Refract Surg 31:879, 2005; Talley-Rostov A: Patient-centered care and refractive cataract surgery.
Curr Opin Ophthalmol 19:5, 2008; Tuan KM: Visual experience and patient satisfaction with wavefront-guided
laser in situ keratomileusis. J Cataract Refract Surg 32:577, 2006; Waheed S et al: Flap-induced and laser-induced
ocular aberrations in a two-step LASIK procedure. J Refract Surg 21:346, 2005.
Educational Objectives
| The goal of this program is to improve outcomes in refractive surgery. After hearing and assimilating this
program, the clinician will be better able to:
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| 1. Calculate intraocular lens power with optimal accuracy.
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| 2. List the advantages of surface ablation vs traditional laser in-situ keratomileusis.
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| 3. Meet patients’ high expectations of refractive surgery.
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| 4. Use mitomycin C in high-risk refractive surgery patients.
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| 5. Determine if a patient with a Crystalens is a candidate for yttrium aluminum garnet (YAG) laser capsulotomy.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning
committee 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. Yoo receives
grant research support from Alcon, and is on the list of speakers for Intralase. Drs. Rodila, Donaldson, Karp, and
Goldman, and the planning committee reported nothing to disclose.
Acknowledgments
This program was recorded at the Cataract and Refractive Surgery Congress, held February 8-9, 2008, in Miami, FL, and
sponsored by the University of Miami Miller School of Medicine. The Audio-Digest Foundation thanks the speakers and the
sponsor for their cooperation in the production of this program.
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