Oct basics for residents

1. By
Ahmed Elsheemy, M.Sc. Ophthalmology
Retinal
OCT

2. Learning objectives
• To know what is OCT
• To know types of OCT imaging
• To know how to describe OCT image
• To recognize the anatomy of OCT out
print

3. Optical Coherence Tomography
(OCT)
It’s an optical analog of ultrasound imaging
that uses infrared light from
a super-luminescent diode

4. The stages of evolution of various
types of OCT :
• The original time-domain (TD-OCT)
• Spectral domain (SD-OCT)
• Swept-source OCT (SS-OCT)

5. Time domain OCT
• Compares a reflected beam of light to a beam of
light from a reference mirror.
• Time delays between the two beams can then be
measured.

6. Spectral domain OCT
This technique uses a spectrometer to measure the difference
in wavelength between the light from the fixed reference arm
and that returning from the tissue. The instrument analyze the
image according to the light wavelength recorded.

7. Swept source OCT
The Swept Source OCT is a huge improvement compared to
Spectral Domain OCT.
In Swept Source, considerable additional details can be seen
due to higher wavelength. Besides that, this wavelength
penetrates more easily through cataracts and hemorrhages.

14. • Cellular layers
The ganglion cell layer, inner nuclear layer and outer nuclear
layer that are mainly comprised of neuronal cell bodies are
weakly reflective.
• The RPE highly reflective even though it is made up of cells
due to its content of melanin pigments.

16. How to describe
OCT image ?
• Reflectivity
• Location

17. Reflectivity of different media

19. OCT imaging
• Macula
• Optic nerve
• OCT angiography

21. OCT
macula

22. Common modes of OCT imaging
Macula
Macular cube radial line scans raster line scans

25. OCT
macular
thickness
map

26. OCT
Optic
disc

29. OCT
GCL
analysis

30. OCT angiography

31. Test your knowledge
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32. Test your knowledge
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33. Test your knowledge
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34. Test your knowledge
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35. Test your knowledge
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36. Test your knowledge
Describe these OCT..
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37. Thanks for your attention