Sarah Moyer, CRA, OCT-CDirector of Ophthalmic Imaging

Kenneth L. Cohen, MDProfessor of Ophthalmology

Kittner Eye CenterDepartment of OphthalmologyUniversity of North Carolina at Chapel HillSchool of Medicine

Clinical Applications of Anterior Segment OCT

No financial interest

What Does Anterior Segment OCT Do?

• 2-dimensional cross section image of the anterior segment– Conjunctiva– Cornea– Anterior chamber– Iris/Angle– Lens– Sclera

Understanding Anterior Segment OCT

• Vendors• How does AS-OCT work?• Technical aspects• What does AS-OCT measure?• How is AS-OCT used clinically?

Image Anterior Segment

• Low magnification image

Image Anterior Segment

• High magnification image

Anterior Segment OCT Vendors

Bioptigen Handheld OCTHeidelberg Spectralis- AAO 2011?Opko Spectral OCT SLOOptovue RT-Vue with CAM

iVueTopcon AAO 2011?Zeiss Visante and Cirrus

Bioptigen

Courtesy of John CarpentierCourtesy of Sunita Sayeram and Joseph Vance

Heidelberg Spectralis

Courtesy of Tim Steffens

Opko Spectral OCT SLO

Courtesy of Opko

Optovue RT-Vue with CAM

Courtesy of Optovue

Courtesy of Bruno Bertoni, CRA, OCT-C and Tamera Davis, CRA

Zeiss Cirrus

4mm scan lengthInternal optics

Software upgrade needed

Zeiss Stratus

This is not FDA approved!

Zeiss Stratus

Courtesy of Alexis Smith, OCT-C, CRA

Zeiss Visante

Courtesy of Zeiss

1 Week After Phaco and 1-Piece Posterior Chamber IOL

Dislocated IOLIOL in the Capsular Bag Tecnis One-Piece Causes of the Dislocted IOL

• IOL not in capsular bag but in ciliarysulcus

• Ruptured zonules• Hole in posterior capsule• Broken haptic• Crimped haptic

Relationship Between the IOL and the Capsular Bag?

• How can I obtain a 2-dimensionsal cross-sectional image of the anterior segment of the eye?

Anterior segment OCT Immersion B-scan ultrasound

Relationship Between the IOL and the Capsular Bag?

4 o’clockIOL haptic truncated

Ultrasound Biomicroscopy (UBM)

• 2-dimensional cross-sectional image of anterior segment

• Multiple meridians

Dislocated IOL UBM

4:004:00

IOL haptic truncated

OCT Versus UBM• 2-dimensional cross-sectional images

of anterior segment• Multiple meridians• OCT provides more fine detail and

magnified image• OCT non-contact versus UBM contact

(water bath)• OCT more useful to the anterior

segment surgeon because easy to use

OCT Versus UBM• MD or photographer performs UBM• Photographer performs OCT• OCT and UBM require communication

between MD and photographerAnatomic structure(s)LocationMagnificationImaging protocol

What Are the Technical Aspects of Anterior Segment OCT?

OCT Specifications ComparisonSpecifications Stratus Cirrus Visante RT-VueDomain Time Spectral Time Spectral

SLD Wavelength 820 840 1310 840

Scan SpeedA-Scans/sec

400 27,000 2,000 26,000

Axial Resolution ≤ 10 μm 5 μm 18 μm 5.0µm

Transverse Res 20 μm 15 μm 60 μm 15µm

Scan Depth 2mm 2mm 6mm 2-2.3mm

Optical Power 750 μW < 725 μW < 6500 µW 750µW

Visante is designed specifically for Anterior Segment OCT.

Time and Spectral Domain OCT

Anterior Segment Specifications

Specifications Visante RT-VueSLD Wavelength 1310 840

Optical Power < 6500 µW 750µW

The longer wavelength of light and stronger optical power allow TD technology to penetrate deeper into the angle.

The shorter wavelength of light and lower optical power make it possible for the SD technology to also image the retina

Anterior Segment SpecificationsSpecifications Visante RT-VueSLD Wavelength 1310 840

Scan Depth 3mm,6mm 2-2.3mm

Scan Length 10mm, 16mm

1-2,1-6

Higher Wavelength allows for deeper scan depth and longer scan length

More scan depth is able to image cornea to lens

Longer scan length can image limbusto limbus.

Graphic modified from Zeiss graphic

6x16 3x10

2x6 2x1

OCT Image Comparison

Stratus 3mm

Visante 16mm

Cirrus 4mm

RT-Vue 8mmStratus 10mm

RT-Vue 1mmVisante 10mm

Longer scan length gives overviewShorter scan length gives more resolution

Why is Scan Length Important?

• DSEK– Limbus to Limbus Imaging is necessary to

ensure proper attachment of the donor tissue

• Scleral Contact Lens Fitting– Needed to view the entire lens in one image

• Glaucoma– Able to measure both angles from one image.

Slipped DSEK Comparison Longer vs Shorter Scan Length

Courtesy Team Doheny Eye

16mm 10mm

6mm6mm

Text

Scleral Contact Lens

Glaucoma Why Do I Image the Cornea?• Analysis of new corneal transplantation

techniques• Management of postop complications• Document healing of surgical incisions• Plan operations• Management of corneal ulcers• Evaluate extent of tumors of the ocular surface• Measurements of the anterior segment

Fuchs Corneal Dystrophy

• Fuchs dystrophyInherited disease of corneal endotheliumEndothelium dysfunctionalCorneal edemaVision decreases

• Guttae obscure endotheliumSpecular microscopy

Corneal EndotheliumFunction

• Pumps H2O out of the cornea into the anterior chamber

• Keeps corneal stroma at 78% H2O• Transparent at thickness 550 μ• Pachymetry is a measurement of corneal

thickness• Gauges health of cornea

Corneal Edema

Hazy cornea Corneal folds

Fuchs DystrophyTreatment

• Penetrating keratoplasy• Full thickness recipient cornea removed• Full thickness donor cornea sutured into place• 360° full thickness corneal wound• 1 year for visual rehabilitation• Irregular healing of wound results in

variable visual results due to astigmatism

Penetrating Keratoplasty

Epithelial defect

Penetrating Keratoplasty

Irregular healing of full thickness incision

DSEK: Descemet’s Stripping Endothelial Keratoplasty

• Diseased endothelium removed (30 μ)• Donor endothelium and stroma inserted

(~150 μ)• Small incision (5 mm)• Rapid healing and visual rehabilitation in

30 to 60 days

OCT to Monitor Health of DSEK

• Position• Attachment of graft to recipient• Quality of interface• Corneal thickness

DSEK

1 D

1 W

1 M

1038 μ

687 μ

618 μ

DSEK 4 Weeks Post-op

Ultrasound pachymetry 549 μ

Ultrasound Pachymetry Incorrect

• Normal thickness 550 μ• 30 μ endothelium and Descemet’s

membrane removed• 180 μ donor cornea implanted• Pachymetry after DSEK should be at least

700 μ

DSEK 4 Weeks Postop Visante Flap Tool

Corneal thickness 769 μ

Detached DSEK 1 Day Postop Anterior Segment OCT

• DESK attachment 360° would indicate primary donor failureRequire graft replacement

• DSEK detachmentReattach graft with air

DSEK Reattachment1 day postop 1 week postop

7 weeks postop 4.5 months postop

Malpositioned DSEK Malpositioned DSEK

180° meridian

90° meridian

Slipped inferiorly

Automated Global Pachymetry

770 μ

Available Measurements

• Corneal thickness• Anterior chamber depth• Anterior chamber angle• Incision • Tumor

Corneal Thickness

Corneal thickness 769 μ

Pachymetry Data PointsGlobal Pachymetry

– 16 line scans

– 2048 data points in one map

Pachmate Pachymetry1 data point

Anterior Chamber Depth

Post-Op

5.16 mm3.61 mm

Pre-Op

Measuring Angles Measuring Angles

• AOD: angle-opening distance• TIA: trabecular-iris angle• TISA: trabecular-iris space area

Clear Corneal Incision Clear Corneal Incision

Descemet’s detachment Endothelial misalignment Epithelial misalignment

Endothelial gape Epithelial gape Loss of coaptation

Tumors / Cysts

Unable to use measurement features in Raw Mode

Must understand what is real and what is artifact on the scan

Artifacts Artifacts

• Corneal Reflex• Inverted Image (in Spectral Domain)• Shadowing• Image Averaging• Algorithm Failure

– Pachymetry: Corneal surface lines – Pachymetry: Lids

Corneal Reflex

Inverted ImageSpectral Domain Shadowing? Shadowing

Image Averaging

Top: Non-averaged ScansBottom: Averaged Scans

Averaging

Enhanced High Res Cornea Mode

Measuring with Averaging

Enhanced High Res Cornea Mode

Dewarping

Enhanced Mode

Algorithm Failure Due to Lids

superior inferior

Algorithm Failure Due to Lids

Algorithm FailureDue to Corneal Surface Lines

Algorithm FailureDue to Corneal Surface Lines

Algorithm FailureDue to Corneal Surface Lines

How Else Does Anterior Segment OCT Help Me With Patients?

Visualize Depth of Corneal Scar

DSEK with a scar

Visualize Depth of Corneal Scar

Excellent detail of cornea

Ocular Surface Tumors

• Does the tumor extend into the cornea, sclera, and anterior chamber angle?

• Plan operative procedure

Corneal and ConjunctivalIntraepithelial Neoplasia

Corneal and ConjunctivalIntaepithelial Neoplasia

Infectious Keratitis

• Hazy cornea• Difficult to see extent of corneal involvement• Monitor response to medical therapy

Fungal Corneal Ulcer Anterior Chamber Depth

• Important for IOL calculation• Theoretical prediction formula: Haigis• Required to predict the post-op

position of the IOL• Correct IOL power can be inserted• 0.05 mm ACD error = 0.03 diopter

IOL power error

Pre-op Phaco IOL CalculationAnterior Chamber DepthIOLMaster Visante

4.10 mm

ACD difference = 1.8 mm = 1.08 diopters

Irregular Pupil Gonioscopy

Peripheral anterior synechiae Holes in iris

PAS

PASNormal ciliary body

OCT

UBM

What Are the Issues for Billing Anterior Segment OCT?

CA

NV UT

AZ NM

OR

WA

ID

MT ND

SD

WY

NE

KS

OK

TX

CO

MNWI

IA

IL

AR

LA

MI

INOH

KY

TN

MS AL GA

FL

SC

NC

VAWV

PA

NY

MENH

VT

MA

RICTNJ

DE

MD

HI

AK

DC

MO

Coverage Status for Anterior Segment OCTAs of September 2009

Coverage and payment for 0187T (28 states)

Coverage based on medical necessity (4 states)

Coverage may be gained after MAC transition (8 states)

In progress of requesting coverage via KOLS (4 states)

Carrier declined to cover (6 states)

Billing• 0187-T: Temporary Code, Medicare

reimbursement varied according to Medicare regions

• 92132: AMA established CPT code, Medicare covers this code. Some states may have a Local Medical Review Policy (LMRP) where only specific diagnosis are covered.

• SCANNING COMPUTERIZED OPHTHALMIC DIAGNOSTIC IMAGING, ANTERIOR SEGMENT, WITH INTERPRETATION AND REPORT, BILATERAL

Medicare leads to….• Cigna Government Services: (TN, NC, ID)• Highmark Medicare Services: (PA, DC, MD, DE, NJ)• National Government Service, Inc.: (IN, KY, NY, CT)• First Coast Service Options, Inc.: (FL, Puerto Rico, US

Virgin Islands)NHIC, Corp.: (ME, MA, VT, NH, RI)

• Palmetto GBA: (HI, CA, NV)• Noridian Administrative Services (WA, OR, AK, AZ,

UT, WY, MT, ND, SD)• Cahaba (TN, MS, AL, GA)

Billing Codes• 190.0 MALIGNANT NEOPLASM OF EYEBALL EXCEPT CONJUNCTIVA CORNEA

RETINA AND CHOROID• 190.4 MALIGNANT NEOPLASM OF CORNEA• 224.0 BENIGN NEOPLASM OF EYEBALL EXCEPT CONJUNCTIVA CORNEA

RETINA AND CHOROID• 224.4 BENIGN NEOPLASM OF CORNEA• 364.51 ESSENTIAL OR PROGRESSIVE IRIS ATROPHY• 364.52 IRIDOSCHISIS• 364.53 PIGMENTARY IRIS DEGENERATION • 364.54 DEGENERATION OF PUPILLARY MARGIN

364.55 MIOTIC CYSTS OF PUPILLARY MARGIN• 364.56 DEGENERATIVE CHANGES OF CHAMBER ANGLE • 364.57 DEGENERATIVE CHANGES OF CILIARY BODY• 364.59 OTHER IRIS ATROPHY• 364.60 IDIOPATHIC CYSTS OF IRIS AND CILIARY BODY• 364.61 IMPLANTATION CYSTS OF IRIS AND CILIARY BODY• 364.62 EXUDATIVE CYSTS OF IRIS OR ANTERIOR CHAMBER• 364.63 PRIMARY CYST OF PARS PLANA• 364.64 EXUDATIVE CYST OF PARS PLANA• 364.70 ADHESIONS OF IRIS UNSPECIFIED• 364.71 POSTERIOR SYNECHIAE OF IRIS

Billing Codes• 364.71 POSTERIOR SYNECHIAE OF IRIS• 364.72 ANTERIOR SYNECHIAE OF IRIS • 364.73 GONIOSYNECHIAE• 364.74 ADHESIONS AND DISRUPTIONS OF PUPILLARY MEMBRANES• 364.75 PUPILLARY ABNORMALITIES• 364.76 IRIDODIALYSIS• 364.77 RECESSION OF CHAMBER ANGLE OF EYE• 364.81 FLOPPY IRIS SYNDROME• 364.82 PLATEAU IRIS SYNDROME• 364.89 OTHER DISORDERS OF IRIS AND CILIARY BODY• 365.02 ANATOMICAL NARROW ANGLE BORDERLINE GLAUCOMA • 365.20 PRIMARY ANGLE-CLOSURE GLAUCOMA SPECIFIED • 365.21 INTERMITTENT ANGLE-CLOSURE GLAUCOMA• 365.22 ACUTE ANGLE-CLOSURE GLAUCOMA• 365.23 CHRONIC ANGLE-CLOSURE GLAUCOMA• 365.24 RESIDUAL STAGE OF ANGLE-CLOSURE GLAUCOMA• 365.41 GLAUCOMA ASSOCIATED WITH CHAMBER ANGLE NOMALIES \• 365.42 GLAUCOMA ASSOCIATED WITH ANOMALIES OF IRIS• 365.43 GLAUCOMA ASSOCIATED WITH OTHER ANTERIOR SEGMENT

ANOMALIES• 365.44 GLAUCOMA ASSOCIATED WITH SYSTEMIC SYNDROMES

Billing Codes• 365.51 PHACOLYTIC GLAUCOMA• 365.52 PSEUDOEXFOLIATION GLAUCOMA• 365.59 GLAUCOMA ASSOCIATED WITH OTHER LENS DISORDERS• 365.60 GLAUCOMA ASSOCIATED WITH UNSPECIFIED OCULAR DISORDER• 365.61 GLAUCOMA ASSOCIATED WITH PUPILLARY BLOCK• 365.62 GLAUCOMA ASSOCIATED WITH OCULAR INFLAMMATIONS• 365.63 GLAUCOMA ASSOCIATED WITH VASCULAR DISORDERS OF EYE

365.64 GLAUCOMA ASSOCIATED WITH TUMORS OR CYSTS• 365.65 GLAUCOMA ASSOCIATED WITH OCULAR TRAUMA• 365.81 HYPERSECRETION GLAUCOMA• 365.82 GLAUCOMA WITH INCREASED EPISCLERAL VENOUS PRESSURE• 365.83 AQUEOUS MISDIRECTION• 365.89 OTHER SPECIFIED GLAUCOMA• 370.04 HYPOPYON ULCER• 370.05 MYCOTIC CORNEAL ULCER• 370.06 PERFORATED CORNEAL ULCER• 371.03 CENTRAL OPACITY OF CORNEA• 371.71 CORNEAL ECTASIA• 371.72 DESCEMETOCELE • 371.73 CORNEAL STAPHYLOMA• 379.31 APHAKIA

Billing Codes• 379.31 APHAKIA• 379.32 SUBLUXATION OF LENS• 379.33 ANTERIOR DISLOCATION OF LENS• 379.39 OTHER DISORDERS OF LENS• 996.51 MECHANICAL COMPLICATION OF PROSTHETIC CORNEAL RAFT• 996.53 MECHANICAL COMPLICATION OF PROSTHETIC OCULAR LENS

PROSTHESIS• 996.69 INFECTION AND INFLAMMATORY REACTION DUE TO OTHER

INTERNAL PROSTHETIC DEVICE IMPLANT AND RAFT

Thanks for your help!UNC DoctorsBruce Baldwin, OD, Ph.DCraig Fowler, MDDavid Russell, MDGeorge Escaravage, MDGraham Lyles, MDIsaac Porter, MDJonathan Dutton, MDKenneth Cohen, MD

UNC PhotographersDebra Cantrell, COARona Lyn Esquejo-Leon,

CRA

PhotographersDoheny Eye Institute

Bruno Bertoni, CRA, OCT-CTamera Davis, CRA

Henry Ford Health Systems Alexis Smith, OCT-C, CRA

University of California- DavisEllen Redenbo, CRA, ROUBKarishma Chandra

University of Florida Eye Institute John Carpentier, CRA, OCT-C

Wills Eye InstituteSandor Ferenczy, CRASusan Proietta

BioptigenEric Buckland, Ph.DSunita Sayeram, MSJoseph Vance

HeidelbergTim Steffens

OptovueBill DillworthMark ThomasCarl Denis, CRA

ZeissGreg HoffmeyerRick TorneyTracy MooreGary Michalec, CRA, COACherri Ritter

Kenneth L. Cohen, MDProfessor of Ophthalmology

Sarah Moyer, CRA, OCT-CDirector of Ophthalmic Imaging

smoyer@gmail.comKittner Eye Center, University of North Carolina Chapel Hill, NC