REFRACTIVE SURGERY SYMPOSIUM
| PROPHYLACTIC AND THERAPEUTIC STRATEGIES FOR LASIK FLAP COMPLICATIONS —Terry Kim,
MD, Associate Professor of Ophthalmology and Associate Director, Corneal and External Disease and Refractive
Surgery Services, Duke University Eye Center, Durham, North Carolina
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| Infectious keratitis: streptococcal, fungal, Pseudomonas, Bacillus; incidence uncommon (1:1000 to 1:5000); anterior
chamber reaction, inflammatory white blood cells in stroma, formation of distinct infiltrate; 47% caused by atypical
mycobactera; majority by Mycobacterium chelonae, then Staphyloccus aureus and Staphyloccus epidermidis;
American Society of Cataract and Refractive Surgery (ASCRS) survey—bimodal distribution; early-onset infections
(within 2 wk of surgery) predominantly from Staphyloccus; late-onset infections (≥2 wk) from opportunistic
atypical mycobacteria; rare, difficult to treat, can cause clusters or epidemic of cases; poor response to antibiotics;
treat by flap amputations; usually treated with topical and oral antibiotics for 2 to 3 mo; innovative approach to
nonresponsive infections—use skin-punch trephine to cut flap, improving antibiotic penetration
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| Reducing risk for infection: standardize aseptic environment; sterile prep with povidone iodine 5% around periocular
skin, lids, and lashes; sterile drape over handle of scope; sterile hats, gloves, and masks; minimal reuse of instruments;
avoid ice or water (tap or distilled) under sterile field; use of fourth-generation fluoroquinolones
(moxifloxacin [Avelox], gatifloxacin [Tequin]); use one medication every 5 min 3 times before entering operating
room; antibiotic applied to cornea after flap dry for 3 min; continue prophylactically qid for 4 days; better activity
against gram-positive microorganisms and atypical mycobacteria
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| ASCRS management recommendations: diagnose promptly; lift flap when suspicious infiltrate present; obtain scrapings
for stain and culture; with late-onset infection, consider special stains; in absence of special stains, use blood
agar for atypical mycobacteria; discontinue topical corticosteroids and start oral doxycycline (Vibramycin) to inhibit
collagenases; if infection starts within 2 wk of surgery, start fourth-generation agent, alternating with fortified cefazolin
(Ancef) every 30 min; in patient exposed to hospital environment, substitute cefazolin with fortified vancomycin
(Vancocin) to protect against methicillin-resistant S aureus; if infection starts 2 wk after surgery, recommend use of
fourth-generation agent alternating with fortified amikacin (Amikin) every 30 min; use antibiotics for 2 to 3 mo; decreased
reporting and incidence of infections may be due to prophylactic use of fourth-generation agents
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| Other strategies: flap dislocations, striae, and epithelial ingrowth affect vision and healing; 1% to 20% epithelial ingrowth;
in severe cases, epithelium removed from bed and flap; flap sutured in recurrent cases; in severe trauma cases,
tissue adhesives used to seal and secure flaps; slit lamp examination performed to mark epithelium; important to remove
epithelium from edge; speaker uses Tisseel fibrin adhesive (Baxter) painted onto edge of flap; current adhesives
not ideal, but fibrin adhesives used for sealing conjunctival autograft, pterygium surgery, and recurrent epithelial ingrowth;
advantages of Tisseel—no flap suturing or suture removal; quicker visual recovery time; faster operating
time; technically easy; disadvantages—20 to 30 min setup time; patient discomfort; initially limited visualization;
cost; infection concerns; new self-gelling glues being researched
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| PEARLS FOR RETREATMENT IN LASIK— Terrence P. O’Brien, MD, Tom Clancy Professor of Ophthalmology
and Director, Refractive Surgery and Ocular Infectious Diseases, The Wilmer Eye Institute, Johns Hopkins University
School of Medicine, Baltimore
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| Retreatment: working in biologic system; variable wound healing; uptake of laser energy varies with stromal hydration;
undercorrections and overcorrections may occur after myopic, hyperopic, and astigmatic ablations; avoid using
euphemism of “enhancement”; tends to minimize or trivialize procedure and may give excessive promise to patient;
patients must understand differences between “upgrade” and retreatment using same technology; use of customized
wavefront-guided treatment after conventional laser-assisted in-situ keratomileusis (LASIK; [off-label current use])
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Preoperative Issues
| Informed consent: especially important; separate consent form for off-label use; patients need to understand procedure
not approved by Food and Drug Administration (FDA); possible complications (same as with initial LASIK
or additional issues)
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| Presbyopic patients: retreatment eliminates nearsightedness; patient conducts near tasks; trade-off with distant vision;
bandage contact lens demonstrates effects of retreating residual refractive error; consider retreating one eye at
a time
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| Timing: during early postoperative period, fluctuations in vision especially in higher myopic and hyperopic patients;
do not retreat earlier than 10 to 12 wk; tear film changes lead to destabilization and fluctuation of vision; need 2
stable refractions 1 mo apart
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| Myopic shift: be aware of shift masquerading as undercorrection or regression of effect; lenticular opacification and
concomitant myopia may be factor; always perform dilated exam to check crystal lens before retreatment; if myopic
shift occurs at least 1 yr from time of initial surgery, ensure this is not due to beginning and progression of cataract
formation; LASIK retreatment not recommended; suggest discussion of lenticular surgery; no causal
relationship between LASIK and cataract formation
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| Need for >1 retreatment: be cautious; multiple surgeries increase occurrence of progressive ectasia; evaluate posterior
corneal topography; measure manual keratometry (K) readings; serial pachymetry measurements; initial flap
may be thicker than intended, ie, less residual stroma
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| Contraindications: differentiate between regression and ectasia; may occur in patients with high or relatively low
myopia (treatments of 2 to 3 diopters [D]); if in doubt, delay surgery and observe to ensure ectasia not present
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| K values: important, especially for retreatment; assess preoperatively, estimate postoperative K values depending on desired
correction; in high myopic patients with flat K values (ie, -8 to -9 D with 42 to 41 K values), favorable outcome
may not be achieved; may result in oblate shape or diminution in quality or hyperopic patients with steep K values (46
or 47), resulting in optical irregularities (corneal plana); do not make central cornea flatter than 35 D or steeper than 50
D
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Surgical Technique
| Lifting vs recutting: lifting flap advocated; years after initial LASIK surgery, wounds have only minimal healing at
interface; consider recutting only in cases near conjunctival vascular arcade; significant bleeding in micro- or macropannus,
resulting in extensive fibrosis; pulling limbal stem cells or cutting scar tissue problematic; original flap
too thin or small (due to customized ablation patterns) requires cutting larger-diameter flap; if K not too flat,
choose appropriate microkeratome suction ring; otherwise, buttonhole or incomplete flap results; if lifting pre-existing
flap, review original surgical records to determine location of hinge (superior vs nasal); prevents tearing of
hinge, resulting in free cap; note hinge location in record
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Surgical Elevation Technique
| Technique easy: mark and identify under operating microscope or outline edge of flap using slit lamp and Sinskey
hook or 25-gauge needle; bring patient back into operating room
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| Lifting flap: lift edge at slit lamp; use Sinskey hook to apply pressure perpendicular to scar to “pop in” to interface;
lift flap and carry out; poor visualization creates large abrasion, increasing incidence of epithelial ingrowth; ensure
stroma lifted to elevate flap; sterile technique; peel loose epithelium away from interface toward periphery; use
therapeutic bandage contact lens to prevent ingrowth over flap; minimalist, gentle approach to prevent introduction
of epithelium into interface
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| Cutting flap: know your keratome; measure actual flap thickness; know ring size and depth to avoid problems; consider
recutting deeper than initial flap, possibly larger and more temporally; do not get rolled edge of stroma if second cut
present; patients with previous photorefractive keratectomy—beware of looser epithelium; avoid excessive anesthetic;
ample lubrication before passing microkeratome; patients with previous radial keratotomy (RK)— beware of
very flat corneas; larger ring size (≥9.5 mm); deeper cut; do not cut across epithelial facet; avoid wound gape; mitomycin
(Mutamycin) preferable; prevents “pizza pie syndrome” and ectasia
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| Lifting flap challenges: fibrosis at edge causes tearing; central fibrosis in patients with thin flaps or large ablations
can create iatrogenic buttonhole; clean interface well at time of initial LASIK
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| Laser ablation: most retreatments performed for very low residual refractive errors ±1 D; consider adjusting frequency
(hertz) to minimize effect of microsaccadic eye movements
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| Postoperative issues: epithelial ingrowth 1 wk to few months later; other interface opacities (eg, noninfectious keratitis,
diffuse lamellar keratitis, infectious keratitis, striae)
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| REFRACTIVE LENS EXCHANGE —I. Howard Fine, MD, Clinical Professor of Ophthalmology, Casey Eye Institute,
Oregon Health and Science University, Portland
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| Cataract or lens extraction: safe and efficacious; Advanced Medical Optics (AMO) Array foldable silicon intraocular
lens (IOL) uses 100% of incoming light; 44% of patients have total spectacle independence; 44% need spectacles
only with prolonged reading; 12% use glasses most of time; 2 accommodative IOLs tested; one in Europe; one
in United States—silicone, hinged haptic-optic junctions, larger than capsular bag; optic retroplaced when fitted in
capsular bag; mechanism of action believed to be accommodative effort with redistribution of ciliary body mass;
theoretically causes increased vitreous pressure; cannot routinely and objectively document lens movement, which
is theoretical mechanism of action; contradictory study results between FDA and European data; 100% of FDA-
monitored patients at least 20/30, J3, near distant and intermediate; nearly 71% at least 20/20, J1, near distant and
intermediate; visual acuity not indicative of function; reading speed and ability to read without fatigue indicative
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| Refractive lens exchange data: 73% of patients at least 20/25 or better at all distances; 73% spectacle independent
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| New IOL technology: Technis lens compensates for cornea’s positive spherical aberration by creating negative spherical
aberration in implant; better contrast sensitivity documented; new Alcon IOL similar but has posterior prolate
surface; Bausch and Lomb aspheric or Advanced Optics IOL aberration-free; might be advantageous, does not require
stringent centration or absence of tilt; dual optic IOLs with plus lens attached to minus lens reside more posteriorly;
connected with flexible optics; elasticity of haptics moves positive lens forward, creating more plus-
powered lens; new Israeli technology using piston and polymer arrangement to create bulge with up to 30 D of accommodative
amplitude in primates; Flexi-Optic; Calhoun lens with digital light delivery; can address higher-order
corneal aberrations; intraocular optics far superior to finest custom corneal shaping; Medennium Smart IOL; hydrophobic
acrylic fills capsular bag; no decentrations or glare from edge effects; converts from thin rod at room
temperature to soft gel with previously imprinted dioptic power at body temperature; new technologies stabilize
vitreous face
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| Bimanual refractive lens exchange: do not perform surgery on senior citizen if qualified for cataract surgery under
Medicare; great success with Array multifocal IOLs; create appropriately sized incisions; toric configuration provides
manipulation in incision; accurate, precise tool; for Array, circular capsulorrhexis size ≈5 mm; if capsule ruptured,
want ability to put lens in sulcus and track in capsular bag; gently perform cortical cleaving hydrodissection to
prevent dissection of epinucleus; do not express lens at this time; then hydroexpress lens into plane of capsulorrhexis;
use irrigator on top of lens; no contact between lens and corneal endothelium; carousel lens in plane of capsulorrhexis;
done without ultrasound energy; cortical cleanup achieved by tilting phaco tip into posterior chamber;
vitreous face not trampolined; limbal-relaxing incisions address preoperative astigmatism; separate incision between
2 microincisions to implant IOL; decreased risk for retinal detachment; crystal lens used more frequently; similar
technique with smaller capsulorrhexis (≈4 mm); uses cortical cleaving hydrodissection and hydrodelineation; hydroexpress
endonucleus; soft lenses behave unpredictably; yields higher yttrium aluminum garnet (YAG) rate;
STAAR AQ50-10 excellent lens for implantation in ciliary sulcus; do not trap viscoelastic
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| Refractive lens exchange: will become dominant refractive procedure; intraocular optics superior to corneal implantation;
implantations degrade over time by changing spherical aberration in crystalline lens; no cure for corneal presbyopia;
many patients not surgical candidates; addresses all refractive errors, including presbyopia; advantage of patient
never developing cataracts
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Educational Objectives
| The purpose of this program is to provide the listener with information on the nature and management of cataract and
refractive surgery. After hearing and assimilating this program, the clinician will be better able to:
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 | 1. Review the causes and treatment of infectious keratitis after LASIK.
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| 2. Discuss additional strategies to reduce LASIK flap complications.
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| 3. List the preoperative steps involved before retreating patients.
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| 4. Describe the surgical techniques used in retreatment.
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| 5. Summarize new intraocular lens technologies.
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Discussed on This Program
Amikacin sulfate [Amikin]
Cefazolin sodium (Ancef, Zolicef)
Doxycycline [Adoxa, Bio-Tab, Doryx, Doxy 100, Doxy 200, Doxy Caps, Doxychel Hyclate, Monodox, Periostat,
Vibramycin, Vibra-Tabs]
Gatifloxacin [Tequin, Zymar]
Mitomycin (mitomycin-C; MTC) [Mutamycin]
Moxifloxacin [Avelox, Avelox I.V., Vigamox]
Povidone iodine [several trade names]
Vancomycin [Vancocin, Vancoled]
Suggested Reading
Anderson NJ, Hardten DR: Fibrin glue for the prevention of epithelial ingrowth after laser in situ keratomileusis J
Cataract Refract Surg 29:1425, 2003; Ashire R et al: Topical antibacterial therapy for mycobacterial keratitis: potential
for surgical prophylaxis and treatment Clin Ther 26:191, 2004; Azar DT et al: Characteristic clinical findings and
visual outcomes J Cataract Refract Surg 29:2358, 2003; Hersh PS et al: Incidence and associations of retreatment after
LASIK Ophthalmology 110:748, 2003; Hoffman RS et al: Refractive lens exchange as a refractive surgery modality
Curr Opin Ophthalmol 15:22, 2004; Hofling-Lima AL et al: In vitro activity of fluoroquinolones against
Mycobacterium abscessus and Mycobacterium chelonae causing infectious keratitis after LASIK in Brazil Cornea
24:730, 2005; Horgan N et al: Refractive lens exchange in high myopia: long term follow up Br J Ophthalmol
89:670, 2005; Jabbur NS et al: Survey of complications and recommendations for management in dissatisfied patients
seeking a consultation after refractive surgery J Cataract Refract Surg 30:1867, 2004; Kang PC et al: Novel
tissue adhesives to secure laser in situ keratomileusis flaps J Cataract Refract Surg 31:1208, 2005; Karp CL et al: Infectious
keratitis after LASIK Ophthalmology 110:503, 2003; Lafond G et al: Retreatment to enlarge small excimer
laser optical zones using combined myopic and hyperopic ablations J Refract Surg 20:46, 2004; Lafond G et al:
Treatment of previous decentered excimer laser ablation with combined myopic and hyperopic ablations J Refract
Surg 20:139, 2004; Lifshitz T et al: Peripheral sterile corneal infiltrates after refractive surgery J Cataract Refract
Surg 31:1392, 2005; Lyle WA, Jin GJ: Laser in situ keratomileusis for consecutive hyperopia after myopic LASIK
and radial keratotomy J Cataract Refract Surg 29:879, 2003; Najjar DM: LASIK risk score: an easy method to predict
postoperative outcome J Refract Surg 21:399, 2005; Netto MV, Wilson SE: Flap lift for LASIK retreatment in
eyes with myopia Ophthalmology 111:1362, 2004; Oral D et al: Hyperopic laser in situ keratomileusis in eyes with
previous radial keratotomy J Cataract Refract Surg 31:1561, 2005; Peng Q et al: Interface fungal infection after laser
in situ keratomileusis presenting as diffuse lamellar keratitis. A clinicopathological report J Cataract Refract Surg
28:1400, 2002; Prandi B et al: Influence of flap thickness on results of laser in situ keratomileusis for myopia Refract
Surg 20:790, 2004; Shaikh NM et al: The safety and efficacy of photorefractive keratectomy after laser in situ
keratomileusis J Refract Surg 21:353, 2005; Sharma N et al: Refractive outcomes of laser in situ keratomileusis after
flap complications J Cataract Refract Surg 31:1334, 2005; Solomon R et al: Infectious keratitis after laser in situ
keratomileusis: results of an ASCRS survey J Cataract Refract Surg 29:2001, 2003; Taneri S et al: Safety, efficacy,
and stability indices of LASEK correction in moderate myopia and astigmatism J Cataract Refract Surg 30:2130,
200.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lectures to disclose any significant financial
relationship with the manufacturer or provider of any commercial product or service discussed. For this issue,
Dr. Kim has disclosed that he is a consultant for Alcon, Allergan, Bausch & Lomb, and Hyperbranch Medical Technology,
Inc. Dr. O’Brien has disclosed that he is a consultant for Alcon, Allergan, Bausch & Lomb, Eyetech, Inspire,
Pfizer, Santen, and Visx. Dr. Fine has disclosed that he is a consultant for Advanced Medical Optics, Alcon, Bausch
& Lomb, Carl Zeiss Meditec, Eyeonics, Rayner, and STAAR Surgical.
Drs. Kim, O’Brien, and Fine were recorded at the Cataract and Refractive Surgery Congress, held February 25-26,
2005, in Coral Gables, Florida, and sponsored by the Bascom Palmer Eye Institute of the University of Miami Miller
School of Medicine. The Audio-Digest Foundation thanks the speakers and the Bascom Palmer Eye Institute for their
cooperation in the production of this program.
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