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JCAHPO Regional Meetings

2017

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Sarah Armstrong, CRA, OCT-C, FOPSManager of Ophthalmic Imaging

Kenneth L. Cohen, MDSterling A. Barrett Distinguished Professor

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

Clinical Applications of Anterior Segment OCT

No financial interest

Understanding Anterior Segment OCT

• Anatomy

• Vendors

• Clinical use of AS-OCT

• Technical aspects

• Measurements

• Artifacts

• Recent Cases

What Does Anterior SegmentOCT Do?

2-dimensional cross section image of the anterior segment

Anterior Segment AnatomyLimbus Cornea

Angle

Anterior ChamberIris

LensPupil

Ciliary Body

Corneal AnatomyAir/Tear Interface

EpitheliumTear Film

StromaEndothelium

Keratoconus

Bullous Keratopathy

Hydrops

DSEK with fold

Cornea

Photo Credit: Media Resources Centre University Hospitals of Wales Cardiff UKThanks Chris Tetley!

Iris Cyst

Iris Neoplasm

Open Angle

Closed AngleElevated IOP

Iris and Anterior Chamber Angle

Iris Cyst

Narrow Occludable Angle

Martha Leen, M.D. & Paul Kremer M.D. Achieve Eye and Laser Specialists, Silverdale, WA

LensAnterior Chamber IOL

Slipped Lens

Capsular Block

Natural Lens

K-Pro Courtesy Mark Thomas and Ellen Redenbo

Anterior Chamber IOL

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Conjunctiva and Sclera

Conjunctival Lesion

Scleral BucklePterygium

Filtering BlebCourtesy of Achieve Eye and Laser Specialists

BioptigenEnvisu

Heidelberg Spectralis

Nidek RS-3000

Optos OCT/SLO

Optovue Avanti/RT-Vue/iVue

TopconMaestro/Triton

ZeissVisante/Cirrus

OPMI LUMERA 700 and RESCAN 700

Zeiss CirrusWhy Do I Image theAnterior Segment?

1 Week After Phaco and 1-Piece Posterior Chamber IOL

Dislocated IOLIOL in the Capsular Bag

Abbott Tecnis 1-Piece IOL

Causes of the Displaced IOL

• IOL not in capsular bag but in ciliary sulcus

• Ruptured zonules

• Hole in posterior capsule

• Broken haptic

• Crimped haptic

Relationship Between IOL and 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

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Relationship Between IOL and Capsular Bag?

Horizontal meridianIOL optic and posterior capsule

Relationship Between the IOL and the Capsular Bag?

Haptics located in 10-4 o’clock meridianIOL haptic at 10 o’clock proper position

Relationship Between the IOL and the Capsular Bag?

4 o’clock IOL haptic truncatedIOL optic shifted towards 4 o’clock

Anterior Segment OCTTechnical Specifications

Manufactuer Model Domain Scans/secAxial Res Trans Res

Scan Depth

Scan Length Lens

BioptigenEnvisu R2300 Spectral 32,000 <4 μm

21μm, 11μm, 7.5μm* 2.5mm 20mm Ext

Heidelberg Spectralis Spectral 40,000 3.9 μm 14 μm 1.9mm 16mm Ext

OptosOptos

OCT/SLOSpectral

27,000<6.0 μm 20 μm

2.0-2.3mm

6mmExt

Optovue RT-Vue Spectral 26,000 5.0 μm 15 μm2-

2.3mm 12mm Ext

Topcon Maestro Spectral 50,000 6 μm 20 μm 3-6mm 3-6mm Int

Zeiss Cirrus Spectral 27,000 5 μm 15 μm 2mm 4mm Int

Zeiss Visante Time 2,000 18 μm 60 μm 6mm 16mm Int

OCT Specification Comparisons Time and Spectral Domain OCT

Time and Spectral Domain OCT Anterior Segment Specifications

Specifications Visante Spectral

SLD Wavelength 1310 840-870

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 Spectral

SLD Wavelength 1310 840-870

Scan Depth 3mm,6mm 1.9-2.3mm

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 limbus to limbus. *Heidelberg is exception

Graphic modified from Zeiss

6x16 3x10

2x6 2x1

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Shorter Scan LengthBetter Resolution

The following two slides show one individual wearing a +13.50 soft contact lens

Longer scan length gives

better overview

Importance of Scan Length

• DSEKLimbus to limbus imaging is necessary to ensure proper attachment of the donor tissue

• Scleral Contact Lens FittingNeeded to view the entire lens in one image

• GlaucomaAble to measure both angles from one image.

Detached DSEK Comparison Longer vs Shorter Scan Length

Courtesy Team Doheny Eye

16mm 10mm

6mm6mm

Text

Scleral Contact Lens Glaucoma

New Corneal Transplantation Techniques

Why Does this Patient Have Corneal Edema?

Hazy cornea Stromal and epithelial edema

Fuchs’ Corneal Dystrophy

• Fuchs’ dystrophy

Inherited disease of corneal endothelium

Endothelium dysfunctional → edema

Pumps H20 out of cornea

Thickness 550 µ → transparent

Pachymetry

• Specular microscopyGuttae

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Penetrating KeratoplastyProblems

Epithelial defect

Full thickness corneal transplant360° corneal incision and sutures

Penetrating Keratoplasty

1 year for visual rehabilitationIrregular healing of full thickness incision

Visually disabling astigmatism

New TreatmentDSEK: Descemet’s Stripping

Endothelial Keratoplasty• Diseased endothelium and Descemt’s

membrane removed (30 μ)

• Donor endothelium and stroma inserted (~150 μ)

• Small incision (5 mm)

• Rapid healing and visual rehabilitation in

30 to 60 days

DSEK Video OCT to Monitor Health of 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

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Detached DSEK 1 Day Postop Anterior Segment OCT

• DESK attachment would indicate primary donor failure

Require graft replacement

• DSEK detachment

Reattach graft with air

DSEK ReattachmentAir Injection

1 day postop 1 week postop

7 weeks postop 4.5 months postop

Malpositioned DSEK Malpositioned DSEK

180° meridian

90° meridian

Slipped inferiorly

What Else Can be Measured With the OCT?

Protocol

• Need protocol for what is imaged

• There are no criteria

• Must define and establish

Available Measurements of theAnterior Segment

• Corneal thickness

• Anterior chamber depth

• Anterior chamber angle

• Incision

• Tumor size and depth

Automated Global Pachymetry

770 μ

Pachmate Pachymetry1 data point

Global Pachymetry16 line scans2048 data points in one map

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Corneal Thickness

Corneal thickness 769 μ

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 Lack of coaptation

Iris Tumors

Unable to use measurement features in Raw Mode

Must understand what is real and what is an artifact

Artifact on the Scan Artifacts

• Corneal Reflex

• Inverted Image (in Spectral Domain)

• Shadowing

• Image Averaging

• Algorithm FailurePachymetry: Corneal surface lines

Pachymetry: Lids

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Corneal ReflexInverted Image

Spectral 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

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Algorithm Failure Due to LidsAlgorithm Failure

Due to Corneal Surface LinesOCT is a Tool Useful for Following

Clinical Problems

Visualize Depth of Corneal Scar

DSEK with a scar

Visualize Depth of Corneal Scar

Excellent detail of cornea

Flattening of corneal surface over scar

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

• Follow disease process

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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 Depth

IOLMaster Visante

4.10 mm

ACD difference = 1.8 mm = 1.08 diopters

Anterior segment measurement for IOL calculation

Irregular Pupil

Peripheral anterior synechiae Holes in iris

PASAnatomy: Normal ciliary body

OCT

UBM

Essential Iris Atrophy OCT Defines Clinical ProblemAssists Managment

• Depth of corneal scar

• Amount and depth of corneal inflammation

• Position of DSEK graft

• Shape of cornea

• Location of IOL

• Measurements of anterior segment

• Anatomy of the anterior segment

Traumatic Cataract Traumatic Cataract Video

Confirms Etiology

Helps With Management

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Corneal Edema with Hydration

OCT to Confirm Etiology and Management

Corneal Edema with Hydration of Phaco Incision Video

CD: 1845

482µ

1 day post-op 1 month post-op s

Diagnosis of Corneal ShapeConfirms Clinical Diagnosis

541µ→525µ→534µ→581µ

Pellucid Marginal Corneal Degeneration

Center → Periphery

Keratoconus

408µ→382µ→420µ→482µCenter → Periphery

Femtosecond LaserCataract Surgery

New Use of Anterior Segment OCT

Measures the Anterior Segment

Laser Guided Surgery

Input Plan of Operation

Computer Assisted Treatment PlanCataract Surgery

How Does the Laser Work?Spot Size and Bubbles

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Real Time OCT to Guide LaserAnterior Segment and Cataract

Localized With OCT

400 µ safety zone1200 A-scans/secondTotal ~10,000 scans

Tri-Planar Cataract IncisionLocalized with OCT

Sequence of Treatment

Capsulotomy Lens Fragmentation Incisions

Laser Assisted Cataract Surgery

Laser Assisted Cataract Surgery

CapsulotomyFragmentation of cataract

Arcuate keratotomyAstigmatism management

1 Week Post-Op Laser Incision

Ophthalmic Photographers’ Societywww.opsweb.org

Mid-Year ProgramDenver, COSpring, 2018

• National and regional lectures, symposia and workshops

• Educational scholarships

Ophthalmic Photographers’ Society Education

New Orleans, Louisiana

OPS Annual Program

November 10-13, 2017

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Ophthalmic Photographers’ Society Online Education

Webinars via www.opsweb.org

SEPTEMBER DECEMBER

EyeCareCE via https://eyecarece.jcahpo.org/

ANYTIME

Certified Retinal Angiographer (CRA) -accredited by NCCA

Optical Coherence Tomographer-Certified (OCT-C)

Ophthalmic Photographers’ Society Certification

Ophthalmic Photographers’ Society Community

• Professional Journal

• Career Center

• Active online community (forums, blogs, interest groups)

• Social media presence (Facebook, Twitter, Pinterest)

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

AbbottTrevor Wilson

BioptigenEric Buckland, Ph.DSunita Sayeram, MSJoseph Vance

HeidelbergTim Steffens

OptovueBill DillworthMark ThomasCarl Denis, CRA

ZeissGreg HoffmeyerRick TorneyTracy MooreGary Michalec, CRA, COACherri Ritter sm

Kenneth L. Cohen, MDSterling A. Barrett Distinguished Professor

Sarah Amrstrong, CRA, OCT-C, FOPSManger, Ophthalmic Imaging

smoyer@gmail.com

Kittner Eye Center, University of North Carolina Chapel Hill, NC