Outline
The Cirrus
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Acquisition
Glaucoma Analysis
Guided Progression Analysis (GPA)
Macular Thickness Analysis
Macular Change Analysis
Pitfalls
How to Use that Magical Device
and What Does It All Mean
Acquisition – Image Capture
Acquisition – Image Capture
• Iris
– Focus Iris
– Center pupil
• Move off-center if lens/vitreous opacity
• Fundus
– Focus on BV
– Center cube over ONH/Macula
– Uniform illumination
• OCT Scan
– Center OCT scan
– Good reflectance
Acquisition – Image Review
Acquisition – Image Review
• Fundus image
– Sharp, centered en-face image
– Uniform illumination
– Minimal movement distortions
• OCT image
– Centered (preferably in all windows)
– Even signal distribution
– Good signal strength
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Glaucoma Analysis
Glaucoma Analysis
• Optic Disc Cube: 200 x 200
– 200 Horizontal Line with 200 A-scans
– Additional A-scans for Optic Disk
– Only Scan for Glaucoma Analysis
En Face Image
Reliable Scan
• RNFL
– En Face Image
– Extracted RNFL Circle Scan
– RNFL Thickness Map
• ONH
3.46mm
diameter
circle
6mm x
6mm cube
– Fundus Image with OCT Overlay
– ONH Tomogram
Centered RNFL Calculation Ring?
Movement Distortions?
Extracted RNFL Circle Scan
RNFL Thickness Map
Miscalculations?
Complete Scan?
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Fundus Image with OCT Overlay
ONH Tomogram
Cup-to-Disc Calculation?
Cup-to-Disc Calculation?
Clinically Relevant
RNFL Calculations
• RNFL Calculations
– Thickness Profile (TSNIT)
– Quadrants/Clock Hours
– Average Thickness/Asymmetry
– Thickness Map
• ONH Calculations
– Disc Values
– Rim Thickness
– ONH Tomograms
ONH Calculations
Glaucoma
Analysis
Print Out
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Guided Progression Analysis
• Compares 3-8 exams at the same time
• First two scans/exams are baseline
• First scan defines registration for all future
scans automatically and can’t change
• Automatic GPA only includes scans of
signal strength 6 or higher
• Can reset baseline if needed
Guided Progression Analysis
• RNFL Thickness Map Progression
• RNFL Thickness Profile Progression
(TSNIT Curves)
• Average RNFL Thickness Progression
– Average, Superior, Inferior
Macular Thickness Analysis
GPA
Print Out
• Macular Cube: 512 x 128
– 128 Horizontal Lines with 512 A-scans
– Greater Individual Line Resolution
– Increased Line Spacing (~47um)
• Macular Cube: 200 x 200
– 200 Horizontal Lines with 200 A-scans
• Except central horizontal/vertical has 1000 A-scans
– Greater Resolution from Top to Bottom of Scan
– Decreased Line Spacing (~30um)
Macular Thickness Analysis
Macula Thickness Map
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Macula Line Scan
Macular Thickness Significance Map
Miscalculations?
3-D Surface Map – ILM Layer
3-D Surface Map – RPE Layer
Macular Change Analysis
Macula
Thickness
Report
• Compare two macular scans of the same
type side by side
• First scan defines registration
automatically, but can complete manually
• Automatic Change Analysis compares
current exam to most recent exam
– includes scans of signal strength 6 or higher
• Manual Change Analysis compares
current exam to the specified exam date
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Macular Change Analysis
Pitfalls
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Inverted Scan
Scan Too High
Decentered RNFL Calculation Ring
Poor Cube Centration
Poor Pupil Centration
Movement Defect
Blink Defect
Partial Loss of Signal
Poor Signal Strength
Inverted Scan
Inverted Scan
Scan Too High
Scan Too High
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Decentered RNFL Calculation Ring
Decentered RNFL Calculation Ring
Poor Cube Centration
Poor Pupil Centration
Movement Defect
Blink Defects
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Blink Defects
Blink Defects
Blink Defects
Partial Loss of Signal
Partial Loss of Signal
Poor Signal Strength
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