maximizing oct interpretation in glaucoma = maximizing care · maximizing oct interpretation in...

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Maximizing OCT Interpretation in Glaucoma = Maximizing Care

James L. Fanelli, OD, FAAO

jamesfanelli@CEinItaly.com

COPE # 63228-GL

Disclosures

• Dr. Fanelli has received support and/or honoraria from:– Heidelberg Engineering Advisory Board

– Glaukos Advisory Board

– AAO FDR research support SENSA study

– Review of Optometry editor

– CE in Italy/Europe

• There are no conflicts of interest involved with this presentation

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Key Points

• Know Your Technology

• Approaching the New Patient

• Approaching the Established Patient

• Non Glaucomatous Optic Nerve Findings

Knowing your Technology

• Why is this important?

– Knowing what your technology DOES.

– Knowing what your technology DOES NOT do.

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Knowing Your Technology

• Reference Data Base

• Resolution and Registration

Comparison with a Reference Database

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N S T I N

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Thickness measurements and comparison with a reference database

Thickness measurements and comparison with a reference database

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Reference Data Bases

• Are statistical measures only

• Are comparative measures

• How does your patient stack up against other ‘like’ individuals– Reference data base debates

– Good?• Where does your patient fit in

– Bad?• Too inclusive or too exclusive

Reference Data Bases

• Do NOT tell you if a patient has glaucoma

• Do NOT make diagnostic decisions based on them solely….they are one piece to the puzzle

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Reference Data Bases

Need other G-H image showing normal green with sectoral defect

Resolution and Registration

• Is a 10 micron difference significant?

– Depends on where you’re looking

• Eg ganglion cell layer vs entire retina

• Are you looking in the same place?

– Think about CSR

– VERY important—CHANGE?

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Significant Change???

Where Does G Damage Occur

• At the optic nerve of course!

• Near the Optic Nerve

– Namely, the perioptic RNFL

• Also in the Macula

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• The majority of patients in OHTS who developed glaucoma had defects in the optic disc only1

1. Kass et al. Arch Ophthalmol 2001

Disc change only 57%

Field change

only 33%

Both 10%

OHTS converters

Structure vs. Function: Initial detectable damage

WHERE DOES THE DAMAGE OCCUR????

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RNFL Evaluation

Glaucoma RNFL scan

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3.5 mm, 4.1 mm and 4.7 mm RNFL scans

• RNFL thickness decreases as distance from BMO margin increases

• Slope of this decrease over time may provide very useful information about progressive loss of RNFL

▪ Rate of RNFL loss may be faster or slower depending on distance from BMO margin

▪ The combination of RNFL thickness from three different distances may provide complementary information

Comparison with a Reference Database

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NeuroRetinal RimBruchs Membrane Opening

Optic Nerve Head

Image Source: http://www.oculist.net/downaton502/prof/ebook/duanes/graphics/figures/v7/0010/023f.jpg

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Spectral domain optical coherence tomography (SD-OCT): Detailed cross-sectional and 3D images of the eye

BMO: Where we are in Glaucoma Evaluation

Objective Landmark of Inner Edge of Rim

• The most anterior part of ONH contains the optic nerve fibers which make up the neuroretinal rim

• It is separated from the vitreous by the inner limiting membrane of Elschnig (ILM)

• ILM is an objective inner boundary of neuroretinal rim tissue that is consistently detected by SD-OCT

Vitreous

ILM

Nerve fibers

BMO

Alexandre S.C. Reis, Glen P. Sharpe, Hongli Yang, Marcelo T. Nicolela, Claude F. Burgoyne, Balwantray C. Chauhan. Optic disc margin anatomy in patients with glaucoma and normal controls with

spectral domain optical coherence tomography. Ophthalmology 2012. Apr;119(4):738-47

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Disc Topography

Reference Plane

Cup margin

Disc Margin

Disc Topography

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Disc Topography

Advanced OAG

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Advanced OAG

Disc Topography

3D DISC REPORT 3D DISC OU REPORT 3D DISC WIDE REPORT

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Macular Region Evaluation

• Glaucoma is a disease manifest by ganglion cell losses

which are reflected in loss of axons or ONH cupping

• Ganglion cell layer is multi-layered in the macular region –

with NFL, 40% of total retinal thickness

• The majority of the entire retinal ganglion cell population is

in the macula (> 50% of all the ganglion cells)

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Why should we be Interested in the Macula in Glaucoma?

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Topography of Ganglion Cells

Curcio CA, Allen KA..

J Comp Neurol 1990;300(1):5-25

•Large variation in total ocular axonal

count (0.5 to 1,2 mil) among normals

and thus large variation in normative

databases.

•

•However, the variation in ganglion cell

numbers in the central macula is small.

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• Overall retinal thickness vs GCL alone thickness

• It is displayed as a color coded thickness map for a 8 x 8 grid centered on the foveal pit. The grid is positioned symmetrically to the fovea-to-disc axis for each eye

• The area is divided into small 3° x 3° square areas and the mean retinal thickness of each small square is displayed

Macular Thickness

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Macular Thickness in G

• Overall retinal thickness can be influenced by several diseases

– AMD, macular dystrophies etc

• THINNER READINGS

– ERM, VMT etc

• THICKER READINGS

• Macular Ganglion Cell Layer Thickness

– Less influenced by comorbid macular disease

Comparison with a Reference Database

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Remember

• OCT analysis in the macular region can evaluate:

• Ganglion Cell Layer– cell bodies (of ganglion cells)

• RNFL– Axons (of ganglion cells)

Different Macular Locations

• The axons of ganglion cells are visible around the optic nerve

• The cell bodies are centered around the foveal avascular zone

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Case

• 59 y/o Caucasian male

• Glaucoma suspect OU

• Thinned IT NRR

• Scans have shown no change over time

• Large discs, large cups

Macula Deviation Maps, Full Retina, OD

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Macula Deviation Maps, RNFL, OD

Macula Deviation Maps, GCL, OD

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Case

• 66 year old Caucasian female

• Referred by primary care because of ‘cataracts’

• IOP 20mmHg OD, 22mmHg OS

• Clinical C/D 0.6x0.65 0.65x0.8

• Pachymetry: 507 501

Deviation Map Ganglion Cell Bodies

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Deviation Maps RNFL Loss

Visual Fields

• The visual field relatively under-samples the

macula

• The visual field is relatively less sensitive to

ganglion cell loss in the macula

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The Macula in Relation to the Visual Field

230 ganglion cells per size III target

35 ganglion cells per size III target

10 ganglion cells per size III target

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The Macula in Relation to the Visual Field

Central 20°

50% ganglion cells

16/54 Humphrey 24-2 test points

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Furthermore….

• Move toward 10-2 or Selective Perimetry

– FDF

– FDT

– Stimulation of M-ganglion cells

• SAP 24-2 (WOW) perimetry in early glaucoma often times does not identify field defects

Structure / Function relationship

• Non-linear relationship

• Significant loss of RNFL before visual field defect is detectable

• OCT detects glaucoma up to 8 years before visual field loss

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HOOD GLAUCOMA REPORT

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Case

• 47 y/o AA female

• Moderate myopia

• Maternal g mother +G

• IOP 20 mmHg 18 mmHg

• Suspect discs

• IT thinning, IT RNFL defect…??? ST defect??

IMAGEnet6 3.0.1

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Case

• 66/M

• IOP: OD 21, OS 17

• Dx: Chronic angle closure glaucoma

• Fhx: N/A

• Diffuse defects seen ophthalmoscopically

IMAGEnet6 3.0.1

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10-2: 5-3-201824-2: 2-14-2019

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Case

• 59/M

• IOP: OD 14, OS 14

• Dx: Normal tension glaucoma

• Fhx: N/A

• Arcuate damage clearly visible

IMAGEnet6 3.0.1

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10-2: 8-13-19Date: 3-29-19

IMAGEnet6 3.0.1

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Questions?

Glaucomatous vs non glaucomatous structural changes

Thinning of the Neuro Retinal Rim

Maintenance of Perfusion of the

Neuro Retinal Rim

Thinning of the RNFL

Preferential Thinning of the ST

and IT RNFL

Glaucoma

Retention of the Neuro Retinal Rim

Pallor of the Neuro

Retinal Rim

Thinning of the RNFLPreferential Thinning of

the Papillo-Macular Bundle PMB

Non G Optic Neuropathies

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41 YO CDMS + previous ON OS

41 YO CDMS + previous ON OS

• Normal Neuro RNFL OD

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41 YO CDMS + previous ON OS

• Aberrant Neuro RNFL OS

Disc Edema

• Papilledema

– Disc edema related to elevated intracranial pressure

• Pseudo-Papilledema

– Disc edema NOT related to elevated intracranial pressure

• Optic disc drusen

• Non glaucomatous optic neuropathies

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Forward Bowing of RPE/BM

Disc Drusen-OCT findings

• Elevation

• Normal RNFL

• No/minimal cup

• Increased reflectance

• Shadowing

• Separation of outer retina

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Disc Drusen- Shadowing & Separation of Outer Retinal Layers

Pseudopapilledema-OCT FindingsNeutral/Negative RPE and BM deflection

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Approach to the New Patient

• There are only 2 questions that need to be answered in glaucoma:

– Is there disease present?

• Initial visits

– Is the patient stable?

• All subsequent visits

Approach New Patient

• Detailed Fundoscopy

– Close evaluation of the optic nerve in vivo

• Photography (camera or laser)

• Pach

• Visual Field*

– After you’ve evaluated for mild vs advanced disease

• OCT Imaging

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Retinal nerve fiber layerNeural rim

LaminaCribrosa

Retinal ganglion cell parameters

OCT and Glaucoma Analysis

Approach to the Established Patient

• Is the patient STABLE?– Change over time???

– Where?

– RNFL

– Macula

– BMO

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Is There Too Much Information to Obtain?

• NO!

• At the end of the day, SUBTLE progression can occur anywhere– The macula– The RNFL– BMO

• Without those baselines, you can miss that early change

The Perfect Angle

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Questions?

THANK YOU!

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Maximizing OCT Interpretation in Glaucoma = Maximizing Glaucoma CareJames L. Fanelli, OD, GAAO

COPE Course#63228-GL

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