This document provides guidance on interpreting optical coherence tomography (OCT) scans of the macula in common retinal diseases. It discusses how to acquire high-quality OCT images and systematically evaluate the scans. Key steps in image acquisition include proper scan centration and verification of data quality. When evaluating scans, the document outlines examining scan quality, overall retinal profile, foveal contour, retinal layers, and identifying any abnormalities. Specific pathologies are demonstrated, such as macular edema, holes, detachments, and changes at the retinal pigment epithelium. Overall, the document serves as a guide for clinicians to optimize OCT image quality and systematically read scans to accurately diagnose and monitor macular diseases.
2. » pros of FDOCT
– accurate
– reproducible
– non invasive
– fast
» good in
– diagnosis
– gold std in some diseases
– monitor objectively
– retinal thickness measurement
– fluid collection
why OCT
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3. How to get the best information
from macular OCT?
» 1. do the RIGHT scan
» 2. read the scan properly
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4. How to get the best information
from macular OCT?
» 1. do the RIGHT scan
» take the best image
» minimise all possible
error
» 2. read the scan properly
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6. Image Acquisition
2. Data verification and validation
– Do it at the end of scanning session
– error in the retinal boundary delineation
– re-do the scan
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7. Image Acquisition
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2. Data verification and validation
– Verify centralizationof the 6 scans
– Retinal map(single eye), retinal
thickness/volume (OU) analyze protocols
»SD should be around 0 mcm
»SD > 30 mcm
» poor centration
» do the scan again
9. • radial
OCT Basic Knowledge :
Scan Patterns for macula
• raster
• cruciate • single
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10. OCT Basic Knowledge :
radial line protocol
– 6X 6mm-long lines, 30’ apart
– Center at foveal center
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11. 3. raster scanning
– to minimize the chance of missing morphological
details
– 8 mm length scan
– best for vitreomacular adhesion
– May hit small lesions that missed on radial
protocol
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OCT Basic Knowledge :
raster scan protocol
13. OCT Basic Knowledge :
Retinal thickness map
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color Thickness (microns)
White >470
red 350-470
Orange 320-350
Yellow 270-320
Green 210-270
blue 150-210
» from radial scan
14. Retinal Thickness
» 1. fundamental of OCT automatic retinal thickness
measurement
– algorithm (math. calculation)
– presumes 2 high reflective structures
• 1. VR surface
• 2. RPE-photoreceptor outer segment interface
– compares the shape of 1 a-scan to adjacent a-scans 14
15. OCT Basic Knowledge :
Retinal thickness map
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» Depth 2 mm
» For thickness map
» Interpolation for thickness between sample point
18. » 2. software delineation of outer neuro-
sensory retinal boundary
» SDOCT sometimes detect innerHRL as
outer boundary of retina
• error in thickness measurement
• may need manual caliper-assisted
technique
– auto VS manual differed by 9.9-38%
• Costa 2004
Retinal Thickness
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21. How to get the best information
from macular OCT?
» 1. do the RIGHT scan
» 2. read the scan properly
» systematic approach
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22. Basic Principles in OCT reading
» Know your retinal histo/histopathology
» Know what is normal : contour/ thickness
» Remember you’re dealing with
» light and its wave properties
» Reflections/ interfaces
» Attenuation/ shadowing
» Always consider image quality/ artefacts
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24. »High reflectivity : NFL/ IS-OS Junction/ RPE-choriocapillaris
»Intermediate reflectivity : plexiform layers
»Low reflectivity : nuclear layers/ photoreceptor outer segment/ vitreous
»Fovea
»Absence of inner retinal layer
»Increased thickness of the photoreceptor layer 24
OCT Basic Knowledge :
Retinal layers in OCT
25. »High reflectivity : NFL/ RPE/ choriocapillatis
»Intermediate reflectivity : plexiform layers
»Low reflectivity : nuclear layers/ photoreceptor outer segment/ vitreous
»Fovea
»Absence of inner retinal layer
»Increased thickness of the photoreceptor layer
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OCT Basic Knowledge :
Retinal layers in OCT
26. »High reflectivity : NFL/ RPE/ choriocapillatis
»Intermediate reflectivity : plexiform layers
»Low reflectivity : nuclear layers/ photoreceptor outer segment/ vitreous
»Fovea
»Absence of inner retinal layer
»Increased thickness of the photoreceptor layer 26
OCT Basic Knowledge :
Retinal layers in OCT
27. • defining inner and outer HRL
• HRL - Highly Reflective Layer
• TD OCT : single line
• FD OCT : 2 lines 27
OCT Basic Knowledge :
Retinal layers in OCT
28. • defining inner and outer HRL
• FD OCT : not 1 line, but 2
• inner line : IS/OS junction
• outer line : RPE choriocapillaris complex
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OCT Basic Knowledge :
Retinal layers in OCT
29. » IS/OS junction
» correlated with VA
» irregularities at the level of inner HRL after MH Sx
prevent VA improvement
» Uemoto 2002, Kitaya 2004, Villate 2005.
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OCT Basic Knowledge :
Retinal layers in OCT
30. IS/OS junction : correlated with VA
RP
localization of missing photoreceptor
component
Jacobson 1998, 2000
cone-rod dystrophy, Best macular dystrophy
prediction of subret./ subRPE deposits
Aleman 2002, Pianta203
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OCT Basic Knowledge :
Retinal layers in OCT
53. 53
» consider looking for ERM/ PVD
traction in difficult DME cases
»5. structured assesment : Preretinal/ Epiretinal
54. DME: high prevalence of perifoveal PVD
Gaucher 2005
favorable macular remodeling in DME
after spontaneous PVD
Watanabe 2000, Yamagachi 2003
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»5. structured assesment : Preretinal/ Epiretinal
55. A,B : PVD
C : VM traction
D. remodel after completion of PVD
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»5. structured assesment : Preretinal/ Epiretinal
56. » Look for areas of abnormal VMT
» Identified areas where thin
hyperreflective band from the vit insert
into the retina
» Look for ERM
» Thin hyperreflective structures which
show multiple areas of attachment and
separation from the inner retinal surface
» may demonstrate free posterior hyaloid
face
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»5. structured assesment : Preretinal/ Epiretinal
67. » macula edema : Characteristics
» diffuse vs cystoid
» Central/symmetric vs asymmetric (eg RVO)
» Remember thickened retina can attenuate
signal
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» 5. structured assesment: Intra-Retinal
68. » Cystic space : Discrete area of
hyporeflectivity
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» 5. structured assesment: Intra-Retinal
69. Case courtesy of Dr. Scott Lee, East Bay Retina Consultants, Oakland, CA, USA
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» 5. structured assesment: Intra-Retinal
70. Mid-retina slab enface view emphasizes the presence of hard exudates in a subject with mild macular
edema
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» 5. structured assesment: Intra-Retinal
74. » Retinal thinning
» Increase transmission of light to the deeper layer
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» 5. structured assesment: Intra-Retinal
75. 75
» 5. structured assesment: Intra-Retinal
» Retinal thinning
» mostly found in late stage of many
diseases
76. IS/OS-Ellipsoid Enface Slab: Hydroxychloroquine toxicity example with classic bull’s eye
maculopathy
Case courtesy of Dr. Scott Lee, East Bay Retina Consultants, Oakland, CA, USA
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» 5. structured assesment: Intra-Retinal
New Smart HD Scans deliver targeted visualizations of critical anatomy
HD 21 Line – more scans covering a larger area to better assess the retina
HD Radial – 12 radial lines with the fovea as the comm