8/5/2014 LASIK AND PRK ZEBRAS PRK PRK PRK LASIK AND PRK ZEBRAS LASIK AND PRK ZEBRAS. Disclosure Statement: Nothing to disclose

M A N A G I N G T H E R O U T I N E A N D L E S SR O U T I N E

LASIK AND PRK ZEBRAS

Dustin Krassin, OD, FAAO

LASIK AND PRK ZEBRAS

MANAGING THE ROUTINE AND LESSROUTINE

DUSTIN KRASSIN, OD FAAO

Disclosure Statement:

Nothing to disclose

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LASIK AND PRK ZEBRAS

MANAGING THE ROUTINE AND LESSROUTINE

DUSTIN KRASSIN, OD FAAO

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PRK

•

History

•First performed on human 1987 •FDA approved 1995

•Wavefront PRK first performed 1999

PRK

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Primary Applications

•Considerations for PRK over LASIK

•I/S ratio >1.5 but less than 2.0

•Forme fruste pellucid?

•Thinner pachs (<480)

•Dry eye

•Patients younger than 35 with questionable topography

•Elevated vertical coma

PRK

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Enhancement considerations

•Decreased epithelial-cell ingrowth risk

•Risk of e-cell with lift increases with longer duration from primary

•Risk of e-cell with lift may increase with femto-flaps versus microkeratome

•

Refractive Results statistically similar to LASIK*

•e.g. visual acuity, contrast sensitivity, induced HOA’s**

*Cochrane Database Syst Rev. 2013 Jan 31, *Cochrane Database Syst Rev. 2012 Jun 13 **Clin Ophthalmol. 2011;5:451-7

PRK

•Management

•EW CL, snug fit, 5 days

•Antibiotics (4th_{gen fluoro or tobramycin with polytrim)} •Avoid more viscous antibiotics (eg Besivance)

• Delayed re-epithelialization observed

•Steroid qid x 5 days, then taper 1-2 weeks

•Loteprednol over longer duration has lower risk of steroid-associated sequelae

•Cycloplegic

•1% cylogel or 5% homatropine day of and at 1 day

•NSAID

•Acuvail up to TID days 2 and 3 prn

•Analgesics po

•Tramodol (50mg) or vicodin (10/330) q4-6 hrs

•Refrigerate gtts prn including preservative-free AT’s

PRK

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Follow-ups

•6 months (monitor for PRK haze in high myopes) •12 months prn

CASE 1

EBMD

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Epithelial Basement Membrane Dystrophy

•Prevalence: 5% (most common corneal dystrophy)* •Pathophys: Underdeveloped hemidesmisomes and

absence of anchoring fibrils

•Symptoms: pain, FB sensation, “sticking” of eyelid upon awakening (RCE), blurred vision, photophobia, epiphora •Signs: Map/Dot fingerprint pattern, less observable in

younger population

•More common in lighter skin population, MGD, OSD, rosacea

*Epithelial_Sloughing_During_Laser_In-Situ_Keratomileusis

Laibson PR. Microcystic corneal dystrophy. Trans Am Ophthalmol Soc 1976; 74: 488-531

EBMD

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Incidence of epithelial sloughing post LASIK*

**

•2.6% with microkeratome •0.6% with femtosecond

•

Incidence of concurrent DLK with epithelial*

**

sloughing

•54.5% - 91%

•

Incidence of concurrent epithelial cell ingrowth with

sloughing*

**

•46 – 71%

*J Cataract Refract Surg. 2010 Nov;36(11):1925-33 **J Cataract Refract Surg. 2005 Oct;31(10):1932-7

EBMD

•

Assessment

•Slit lamp exam including retro-illumination through dilated pupil

•NaFL

•Very useful to visualize subtle map-dot anomalies •Surgical sponge

•Can be used with topical anesthetic to manipulate the epithelium, observing for abnormal wiggling (ie poor adhesion) •History!

•Previous eye injuries

•Any pain or pulling sensation of the eyes upon awakening

EBMD/RCE

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Non-Surgical

Treatment Options for erosion:

•Doxycycline and loteprednol

•Along with BCL, +/-antibiotics, punctal plugs, preservative-free AT’s

•Doxy 50-100mg bid, loteprednol tid x 2-4wks •Why doxy and/or steroid?

•Patient’s with RCE produce more MMP-2 and MMP-9

•MMP’s play a role in remodeling degredation of connective tissue

•Plays a role in breaking down the epithelial adhesion complex

•Tetracyclines inhibit MMP activity

•Recurrence in traumatic etiologies (n=7) post doxycyline therapy was zero*

•Steroid inhibition of MMP is similar to doxy, but slightly less •Combination therapy had the best yield

*Dursun D, Kim MC, Solomon A, Pflugfelder SC. Treatment of recalcitrant recurrent corneal erosions with inhibitors of matrix metalloproteinase-9, doxycycline and corticosteroids. Am J Ophthalmol. 2001 Jul;132(1):8-13.

RCE

•n=21 All received

•oral doxycycline 50 mg twice daily and topical fluoromethalone 0.1% three times daily for at least 4 weeks. •At 8 weeks post commencement of treatment, 15/21 patients

(71%) were symptom free

•All but one of these patients reported an improvement in symptoms. Of those patients not lost to follow up, 15/18 patients (83%) and 11/15 patients (73%) denied any symptoms suggestive of relapse at 6 and 12 months, respectively. •*Among the patients in remission was one who had responded

poorly to other treatments including ocular lubricants, epithelial debridement, serum eyedrops, anterior stromal puncture, and phototherapeutic keratectomy.

EMBD/RCE

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Non-Surgical

Treatment options:

•Autologous serum

•Patient’s blood is centrifuged and serum separated and compounded into a drop

•Shown to have value in persistent epithelial defects*

•Similar biomechanical properties to tears

•Can be costly, cumersome, and have sterility challenges •TIME . . .

•Some post-LASIK EBMD/RCE can take 12 months to stabilize

* Treatment of recurrent corneal erosions using autologous serum. Cornea. 2002 Nov;21(8):781-3.

EBMD/RCE

•Anterior stromal puncture (ASP) •Nonvisual-axis lesions

•Less common as can cause scarring, glare, and blur

•Diamond burr (or #15 scalpel) •Can be used on visual-axis lesions

•Remove epithelium centrally

•Perform keratectomy down to Bowman’s

•Allow for re-epithelialization w/ BCL similar to post-PRK

•PRK/PTK •aka “Laser-scrape”

•After epithelial debridement, excimer laser removes 5-10μof Bowman’s

•Like keratectomy, allows re-epithelialization with stronger adhesion

http://www.aao.org/publications/eyenet/201303/upload/M arch-2013-Ophthalmic-Pearls.pdf

CLAPIKS

•Contact Lens Assisted Pharmcologically Induced Kerato-Steepening

•Application

•For reducing small amounts of hyperopia in refractive surgery patients (myopia?)

•Encourages epithelial proliferation and ant. stromal thickening which can steepen k’s

•Method

•EW CL and topical NSAID

•Higher modulus lens preferred

•Acular TID-QID

•Monitor weekly

•Monitor manifest refraction and k’s

•Can get rebound after d/c so continue to monitor afterwards

•May be more efficacious in post-PRK patients over LASIK due to increased likelihood of epithelial hyperplasia with PRK vs LASIK

http://www.healio.com/optometry/refractive-surgery/news/print/primary-care-optometry-news/%7Bd50d645c-c35f-40f8-86a7-f7f870d016fb%7D/manage-overcorrected-lasik-with-clapiks http://www.usaeyes.org/lasik/library/CLAPIKS.pdf

Contact Lens Spectrum, Issue: April 2007, Earle Scharff, OD

CASE 3

REACTIVE SCARS POST PRK

•

Stromal corneal scars can react to refractive

surgery

•Can induce variable refractive error

•Can have an inflammatory response, which can also be delayed in onset

•Depending on size and density, can put patient at higher risk of PRK haze

•Ex. Traumatic scars, RK scars

•

PRK/PTK can treat certain amounts of anterior

stromal scarring

•Can improve corneal clarity and sometimes improve BCVA’s

REACTIVE SCARS POST PRK

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Intraoperative care needed

•Epithelial debridement needs to be done with care •Anterior aspect of scars (particularly RK) can microperforate

during debridement

•Can affect refractive results

•Understand your surgeons comfort level and experience with PRK over RK

•Can still have excellent results in the hands of an experienced surgeon

•Pt needs to be aware that with previous surgery there is less predictability versus a virgin cornea (also with large traumatic corneal scars)

LASIK

•

History

•First performed on a human 1990 •FDA approved 1999

•Femtosecond-created flaps FDA approved 2001 •LASIK via wavefront technology FDA approved 2002 •Most common refractive procedure worldwide

LASIK

•

Primary Applications:

•I/S ratio’s <1.5* •Pachs: >480μ*

•Residual stromal bed >250μ* •Myopia: -12.00 •Hyperopia: +6.00D •Astigmatism: -6.00D *Surgeon specific

LASIK

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Management

•Antibiotics (4th_{gen fluoro or tobramycin with polytrim)} •Steroid qid x 5-7 days

•Preservative-free AT’s q1-2h

LASIK

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Follow-ups*

*Varies from center to center and clinician comfort level

LASIK

•

Post-LASIK Keratitis

•Incidence: 2.66% (279/10,477 eyes)*

•Non-infectious: 2.35% (246 eyes)

•DLK 78% (193), staph hypersensitivity 16% (36), debris-related keratitis 15% (17)

•Infectious: 0.31% (33 eyes)

•HSK 15% (5), adenoviral 55% (18), non-viral (fungal, parasitic, bacterial) 30% (10)

*J Cataract Refract Surg. 2007 Mar;33(3):474-83.

CASE 5

STERILE CORNEAL INFILTRATES

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Signs/Symptoms:

•Minimal: conjunctival injection, chemosis, discomfort •Good VA’s, occasional folds in Descemet’s •Subepithelial and anterior stromal infiltrates

•Peripherally, near limbus (clear zone in between)

•Often near lid margins

•

Pathophysiology

STERILE CORNEAL INFILTRATES

•Management

•Control and eliminate microorganisms (most commonly S. aureus)

•Tobramycin, ciprofloxacin qid

•Control and eliminate sequelae of the inflammation •Topical steoid depending on level of inflammation

• Lotemax gel TID-QID

• Cycloplegic prn

•Don’t forget about the lids •MGD, ant/post blepharitis

• Eyelid hygiene (may need to hold-off if <1 week from surgery)

• Doxycyline po 50-100mg bid • +/- qhs antibiotic ointment • +/- qhs steroid ointment •Monitor q2-7 days

CASE 6

LASIK

•

Herpes Simplex Keratitis (HSK) post LASIK

•Old HSK can be reactivated by stress, trauma, UV exposure •LASIK/PRK utilize excimer lasers which are a form of UV •Preop disclosure of prior history is imperative

•However, many are unaware of prior history •Variable presentations post LASIK

•May not elicit classic dendritic pattern

•May only have delayed wound healing, increased photosensitivity without obvious corneal findings •Corneal sensitivity testing at preop for patients with

questionable history or old questionable scars

•Scars: feathered, irregular borders, variable density, variable depth,

•Especially in the absence of any traumatic or CL history

HSK POST LASIK OR PRK

•

Management

•Topical antiviral

•Eg Zirgan 5x/day until eptihelium intact, then TID x 7 days •Oral antiviral

•Controversial

• Acyclovir, valacyclovir •Topical steroid

•If sight threatening lesion to decrease scarring

•Inflammation is a bi-product of HSK

•Inflammatory control can be important to manage level of scarring and also variable refractive results due to K changes

•Cycloplegic

•Copious preservative-free AT’s

INACTIVE HSK AND LASIK

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Perioperative prophylaxis*

•Oral valacyclovir •Topical acyclovir

•

Study with patients having known HSK history

•n=5, normal topography, no central scarring, normal corneal sensitivity

•No patient’s had reactivation of the HSK post LASIK

•

Still controversial to Tx with an elective procedure

like LASIK or PRK

*J Refract Surg. 2006 Apr;22(4):404-6.

LASIK

•

Epithelial cell ingrowth

•Incidence 0-20%

•Incidence requiring surgical removal 0.92%-2.2% •Most commonly presents peripherally at corneal-flap

interface

•Occasionally progresses and extends toward visual axis

•Can lead to increased glare, blur, FB sensation

•Can lead to flap melting

•More common in lift-enhancements over primary LASIK tx.

•More mechanical trauma with lifts may yield poor flap adhesion

•Incidence increases with increased time from primary tx •Can occur after PRK enhancement over old LASIK

EPITHELIAL CELL INGROWTH

•

Management*

•Measure size, particularly from edge of flap centrally

•<2mm with no visual or ocular complaints (Grade 1) •Watch acuities and any increase in cylinder

•Monitor, 2-3 weeks

•2mm, normal edge anatomy (Grade 2) •Have surgical evaluation ~2 week

•>2mm, anatomic abnormalities, or rapidly progressing (Grade 3) •Requires urgent treatment

•Monitor for change in size and density

•Ingrowth can also progress anteriorly and thin the stroma including the underside of the flap

•NaFl is a helpful to visualize edge elevation (pooling) or negative staining if flap is focally elevated

*Probst LE, Machat JJ. Epithelial ingrowth following LASIK

CASE 8

LATENT HYPEROPES AND LASIK

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Preop screening

•Full cycloplegic examination in hyperopes

•

Treatment planning based on cycloplegic

refraction and manifest refraction can be

challening

•Full cycloplegic treatment patients may have a higher chance of accepting full plus at the corneal plane vs. spectacle

•But many likely pseudomyopic in early postop phase

•Also many inherently myopic in early postop phase due to nature of hyperopic treatment to avoid regression

LATENT HYPEROPES AND LASIK

•

Patient education

•Set expectations of myopic affect in early phase •Let patient know increased chance of a two-step

procedure if not treating to full cyclo

•

Post-op

•If patient appears myopic

•Check K’s to see if at expected (average k’s) •~Every spherical equivalent diopter of treatment = diopter of

steepening

•Helps confirm if patient is pseudomyopic/hyper-accommodating

PSEUDOMYOPES AND LASIK

•

Postop options

•Ask type of work they do

•Extensive near tasks can stimulate hyperaccommodation •May benefit from ReRx (even if not presbyopic)

•Consider multi-focal CL’s

•Extended wear prn

•Put least minus for distance, low add

•RTO 1 week, push plus OR, replace with less minus CL

•Repeat until desireable endpoint •Consider home-cycloplegic

•1% tropicadmie or 1% cyclopentalate

CASE 9

MEDICAMENTOSA

•A condition that arises from a medication rather from an underlying disease

•Signs/Symptoms:

•Punctate erosions, often grouped/clumped, can also be diffuse

•Often seen at a level greater than expected with post surgical dryness

•Light sensitivity, redness, mild/moderate discomfort, lid swelling, conjunctival chemosis

•Management:

•d/c and switch medications depending on severity and level of discomfort

•Common culprits: polytrim, gentamicin

•Copious preservative-free artificial tears (Minimum: q30min) •Monitor 2-3 days depending on severity

THANK YOU