RTVue 100
The Next Generation OCT
Principles of OCT Technology
• Optical Coherence Tomography (OCT) uses a
principle called low coherence interferometry to
derive depth information of various retinal structures
• This is performed by comparing the time difference
in reflected light from the retina at various depths
with a reference ‘standard’
• Differences between the reflected light and the
reference standard provide structural information in
the form of an ‘A’ scan
Principles of OCT Technology
•An A-scan is the intensity of reflected light at various
retinal depths at a single retinal location
• Combining many A-scans produces a B-scan
Retinal Depth
+
+ ... =
Reflectance Intensity
A-scan
A-scan
A-scans
B-scan
Fourier Domain OCT – RTVue 100
• Optical Coherence Tomography
(OCT) provides cross sectional
imaging of the retina
• Spectrometry and Fourier
Domain methods allow high speed
data capture (26,000 A scans per
second)
• Broad-band light source provides
high depth resolution (5 microns)
The Evolution of OCT Technology
Fourier domain OCT
OptoVue
RTVue 2006
26,000
• 65 x faster
• 2 x resolution
Speed
(A-scans
per sec)
400
Time domain OCT
Zeiss OCT 1
and 2, 1996
100
Zeiss Stratus
2002
16
Resolution
10
(mm)
5
Evolution of Commercial OCT
OCT 1
(Time Domain)
Stratus OCT
1996
2002
(Time Domain)
RTVue
(Fourier Domain)
2006
Time Domain OCT
Lens
Broadband
Light Source
Distance determines
depth in A scan
SLD
Interferometer
Detector
Creates
A-scan
1 pixel
at a time
Reference mirror
moves back and forth
Combines light
from reference
with reflected
light from retina
Scanning mirror
directs SLD
beam on retina
Process
repeated many
times to create
B-scan
Data Acquisition
Processing
Final A-scan
Slide courtesy of Dr. Yimin Wang, USC
Fourier Domain OCT
Reference mirror
stationary
Broadband
Light Source
SLD
Interferometer
Grating splits
signal by
wavelength
Spectrometer
analyzes
signal by
wavelength
Combines light
from reference
with reflected
light from retina
Process
repeated many
times to create
B-scan
FFT
Spectral
Fourier transform
interferogram converts signal to
typical A-scan
Slide courtesy of Dr. Yimin Wang, USC
Entire A-scan
created at a
single time
Time Domain OCT
Fourier Domain OCT
• Sequential
• 1 pixel at a time
• 1024 pixels per A-scan
• 400 A scans per second
• 512 A-scans in 1.28 sec
• Slower than eye movements
• Simultaneous
• Entire A-scan at once
• 2048 pixels per A scan
• 26,000 A scans per second
• 1024 A-scans in 0.04 sec
• Faster than eye movements
Motion artifact
Small blood vessels
IS/OS
Choroidal vessels
512 A-scans in 1.28 sec
1024 A-scans in 0.04 sec
Higher speed, higher definition and higher signal.
Slide courtesy of Dr. David Huang, USC
Fourier Domain OCT
• High speed reduces eye motion artifacts
present in time domain OCT
• High resolution provides precise detail,
allows more structures to be seen
• Larger scanning areas allow data rich maps
& accurate registration for change analysis
• 3-D scanning improves clinical utility
High Speed allows 3-D scanning
B-scans provide high resolution detail
Retinal Layers with RTVue & Histology
Temporal
Nasal
Fovea
Parafovea
ILM
NFL
GCL
IPL
INL
OPL
ONL
PR IS/OS
RPE
Choriocapillaris
and choroid
Macula thickness map reveals edema
RPE Elevation map reveals drusen & CNV
RPE Elevation
map reveals CNV
Change Analysis for macula
Glaucoma Analysis
• RNFL Thickness
Map
• Neural retinal rim
• Cup area
• RNFL TSNIT graph
at 3.45 mm circle
Measuring the ganglion cells
Inner retinal layer provides
Ganglion cell assessment:
• Axons = nerve fiber layer
• Cell Body = ganglion cell layer
• Dendrites = inner plexiform layer
Images courtesy of Dr. Ou Tan, USC
Ganglion cell layer in macula analyzed
for glaucoma
Inner Retina Segmentation
Provides thickness of:
• RNFL layer
• Ganglion cell layer
• Innerplexiform layer
Normal vs Glaucoma
Cup
Rim
RNFL
Inner Retina
Macula Map
Normal
Glaucoma
Retina Examples
Normal
Rod cone dystrophy
Images courtesy of Dr. Jennifer Lim, USC
Cystoid Macula Edema
Courtesy: Michael Turano, CRA
Columbia University.
Courtesy: Michael Turano, CRA
Columbia University.
Diabetic Retinopathy
horizontal
vertical
Images courtesy of Dr. Tano, Osaka University
Central Retinal Vein Occlusion
Images courtesy of Dr. Tano, Osaka University
AMD-Classic CNV
horizontal
vertical
Images courtesy of Dr. Tano, Osaka University
Idiopathic CNV
Images courtesy of Dr. Tano, Osaka University
Macula Hole
horizontal
vertical
Images courtesy of Dr. Tano, Osaka University
Diabetic Macula Edema with
Epiretinal Membrane
Courtesy: Michael Turano, CRA
Columbia University.
Central Serous Chorioretinopathy with PED
56 year old Female
Sub-retinal fluid
PED
early phase FA
Images courtesy of Dr. Tano, Osaka University
Stage 3 Full Thickness Macular Hole
Operculum
Courtesy: Michael Turano, CRA
Columbia University.
Central Serous Chorioretinopathy
Images courtesy of Dr. Tano, Osaka University
Epiretinal Membrane
Images courtesy of Dr. Tano, Osaka University
Retinitis Pigmentosa
Images courtesy of Dr. Tano, Osaka University
Vitreomacular Traction Syndrome with
CME
Courtesy: Michael Turano, CRA
Columbia University.
Patient MB – Neovascular AMD
Fundus Photograph
FA
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient MB – Neovascular AMD
Fluid
accumulation
CNV
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient MB – Neovascular AMD
Full Retinal Thickness Map
Large area of abnormally
thick retina from intraretinal
fluid accumulation
RPE Elevation Map
RPE elevation due to CNV
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient WB – Neovascular AMD
• 86 year old male
Fundus Photograph
FA
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient WB – Neovascular AMD
3-D Evaluation
reveals extent
of CNV
CNV
Date: 1/10/07
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient WB – Neovascular AMD
Full Retinal Thickness Map
Some abnormal thickening
and thinning
RPE Elevation Map
RPE / choroid disruption
identifies presence of CNV
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient WB – Neovascular AMD
Full retinal Thickness
B-scan comparison
1/10/07
2/23/07
Treatment
• 2/7 – Lucentis
• 2/14 – PDT
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Thinning of retina
and improvement
in RPE in response
to treatment
RPE Elevation
Patient ED – Neovascular AMD
• 84 year old male, initial exam 12/13/2006
FA
Full retinal thickness map
RPE elevation map
FA shows leakage just
superior to fovea
Full retinal thickness
shows no thickening
RPE elevation map
clearly shows area of
CNV superior to fovea
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient ED – Neovascular AMD
Initial Exam:
12/13/2006
Follow-up Exam:
3/20/2007
RPE/Choroid shows some
reduction in height, but
overall retinal thickness
increases due to intraretinal fluid accumulation
Treatment
1/17 – Macugen
3/14 - Macugen
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient ED – Neovascular AMD
Total Retinal Thickness increases
RPE elevation decreases
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient WW – AMD
• 76 year old male.
PEDs
Drusen
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Patient WW – AMD
Full Retinal Thickness Map
Full Retinal thickness map
normal
RPE Elevation Map
Localized elevations reveal
location of PED and Drusen
Case courtesy of Dr. Nalin Mehta,
Colorado Retina Center
Comparison of Stratus OCT to RTVue OCT
RTVue
• Fourier Domain OCT
• 26,000 A scans per second
• 5 µm depth resolution
• Retina Assessment
• Dense Full Retinal
Thickness map
• RPE elevation map
• 3-D macula scans
• Glaucoma Assessment
• RNFL map
• Inner Retinal Thickness map
(Ganglion cell assessment ->
axon+cell body+dendrites)
• Optic disc
Comparison
• RTVue is 65 times
faster
• RTVue has twice the
depth resolution
Stratus
• Time Domain OCT
• 400 A scans per second
• 10 µm depth resolution
• Retina Assessment
• Sparse retinal thickness
map for retina (97%
interpolated)
• Glaucoma Assessment
• RNFL ring for glaucoma
(TSNIT curve)
Comparison of Stratus OCT to RTVue OCT
RTVue
• Data Captured: 9510 A scans (pixels)
• Time: 370 msec
• Area covered: 4 mm diameter circle
Provides
•Cup Area
• Rim Area
• RNFL Map
• TSNIT graph
Glaucoma Comparison
• RTVue has 97% more data
• RTVue is over 5 times faster
• RTVue provides
comprehensive glaucoma
information
Stratus
• Data Captured 256 A scans (pixels)
• Time: 1.92 seconds
• Area Covered: ring at 3.45 mm diameter
Provides
• TSNIT graph
Plus, RTVue has exclusive Retinal Ganglion Cell layer assessment
• Data Captured: 14,810 A scans (pixels)
• Time: 570 msec
• RTVue provides direct
• Area covered: 7 x 7 mm
ganglion cell information
• Inner retina analysis:
Provides
• No Comparison
•
RNFL
• Inner Retina Map
• Ganglion cell body
• Ganglion cell
• Inner plexiform layer
assessment in macula
RTVue can provide 3-D imaging of the optic disc and RNFL
• Data Captured: 51,712 A scans (pixels)
• Time: 2 seconds
• RTVue provides 3 D image of
• Area covered: 4 x 4 mm
• No Comparison
optic
disc
and
parapapillary
Provides
RNFL
•3 D map
Comparison of Stratus OCT to RTVue OCT
RTVue
• Data Captured: 19,496 A scans (pixels)
• Time: 780 msec
• Area covered: 5 x 5 mm
Provides
• Dense Retinal
thickness map
Retina Comparison
• RTVue has 96% more data
• RTVue is over 2.4 times faster
Stratus
• Data Captured 768 A scans (pixels)
• Time: 1.9 seconds
• Area Covered: circle 6 mm diameter
• RTVue provides more data
and a more detailed thickness
map
Provides
• Sparse Retinal
thickness map
• 97% interpolated
between lines
RTVue has 3 D imaging of the macula
• Data Captured: 51,7212 A scans (pixels)
• Time: 2 seconds
• Area covered: 4 x 4 mm
Provides
• 3 D map of
the macula
• RTVue provides 3-D image of
macula for a comprehensive
review of B-scans over large
area
Plus, RTVue has RPE elevation map for Drusen and CNV
• Data Captured: 19,496 A scans (pixels)
• Time: 780 msec
• RTVue RPE elevation map
• Area covered: 5 x 5 mm
reveals location and extent of
Drusen and CNV which is
Provides
missed by retinal thickness
• RPE Elevation
maps
map
• No Comparison
• No Comparison
RTVue Details
•
•
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•
•
•
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•
Scan Speed: 26,000 A scans per second
Depth Resolution: 5 microns
Transverse Resolution: 15 microns
Frame Rate: 256-4096 A-scans per frame
Scan Depth 2 mm – 2.3 mm
Scan length 2 mm – 12 mm
SLD wavelength: 840 +/- 10 nm
Focus Range: -15 D to +12 D
Retina scans:
Glaucoma Scans
High res line scan
High res cross scan
Macula Map over 5 mm x 5 mm
3-D macula scan
Nerve Head Map over 4 mm Diameter
Macula Map over 7 mm x 7 mm
RNFL 3.45 scan circle
3-D Optic Disc
Scan Details: Line and Cross
Cross
HD Line
Transv. Res
1024
1
39 msec
line length: 6 mm (adj. 2-12mm)
5.9 µm
1024
2
78 msec
line length: 6 mm (adj. 2-12mm)
5.9 µm
4096
1
156 msec 1.5 µm
line length: 6 mm (adj. 2-12mm)
HD Cross 4096
2
312 msec 1.5 µm
line length: 6 mm (adj. 2-12mm)
line
horizontal
vertical
Line
# Ascans, # Bscans Scan Time
High density line
HD horizontal
HD vertical
Type
Scan Details: 3-D
Type
# Ascans, # Bscans
Scan Time
Transv. Res
3-D Macula
512
101
size: 4x4 mm
2 sec
7.8 µm
3-D Disc
512
101
size: 4x4 mm
2 sec
7.8 µm
Scan Details: Maps
Type
MM5 (Retina)
# Ascans, # Bscans
Scan Time
668
22
400
12
total 780 msec
macula map size: 5x5 mm
NHM4 (Glaucoma) 452
12
587 & 775
6
total 390 msec
map size: 4 mm diameter circle
MM7 (Glaucoma)
Transv. Res
7.5 µm
7.5 µm
7.5 µm
4.3-5.2 µm
467
1
15.0 µm
400
15
total 580 msec 17.5 µm
macula map size: 7x7 mm