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Maximizing OCT Interpretation in Glaucoma = Maximizing Care
James L. Fanelli, OD, FAAO
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
S
N
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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
You have completed the above course to earn 2 Live CE credit hours. Take an image of this
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