This document discusses the interpretation of optical coherence tomography (OCT) images of the retina. It begins by explaining how OCT images expand the retina in the axial direction and identifies key layers such as the inner and outer photoreceptor segments. It then examines pathologies affecting the outer, middle, and vitreo-retinal interface of the retina. New developments discussed include using anterior segment OCT to image the anterior chamber, and spectral domain techniques that provide higher resolution images to better visualize conditions like geographic atrophy. In closing, several OCT devices including Heidelberg Spectralis and Zeiss Cirrus are highlighted.

1. Interpretation of the OCT Image
(and some new developments)
B. Jeroen Klevering
University Medical Centre Nijmegen
-
The Netherlands

2. Topics
• The OCT image
─ Normal retina and key retinal pathologies
a. outer retina
b. middle retina
c. vitreo-retinal interface
─ New developments

3. Optical Coherence Tomography
This is what we wanted…

4. Optical Coherence Tomography
…this is what we got…

5. Interpretation of OCT images
Outer retina
250 !m 500 !m
• The OCT image is expanded in the axial direction

6. Interpretation of OCT images
Outer retina
Inner HRL
Outer HRL
• Inner HRL: junction between inner and outer photoreceptor segments
• Outer HRL: retinal pigment epithelium (probably with choriocapillaris)
• Fovea:
─ absence of inner retinal layers
─ increased thickness of the photoreceptor layer

7. Interpretation of OCT images
Outer retina
High resolution
Spectral Domain
(Fourier
Domain OCT)

8. Key retinal pathologies - outer retina

9. Key retinal pathologies - outer retina

10. Key retinal pathologies - outer retina

11. internal limiting membrane
nerve fiber layer
ganglion cell layer
inner plexiform layer
inner nuclear layer
outer plexiform layer
outer nuclear layer
outer limiting membrane
photoreceptor inner segments
photoreceptor outer segments
retinal pigment epithelium
choriocapillaris

12. Interpretation of OCT images
Layers of the retina
Nerve
fiber
layer
Ganglion
cell layer
Inner
plexiform
layer
Inner
nuclear
layer
RPE and choriocapillaris Outer and inner External limiting Outer Outer
photoreceptor membrane nuclear plexiform
segments layer layer

13. Interpretation of OCT images
Layers of the retina
Nerve fiber layer
Ganglion cell layer
Inner plexiform layer
Inner Nuclear layer
Outer plexiform layer
Outer nuclear layer
External limiting membrane
Inner/outer segment junction
RPE
Larger choroidal vessels
300 !m____
High resolution spectral OCT

14. Key retinal pathologies - middle retina

15. Key retinal pathologies - middle retina

16. Key retinal pathologies - middle retina

17. Key retinal pathologies - vitreo-retinal interface
VA 20/40 following
cataract surgery

18. Key retinal pathologies - vitreo-retinal interface

19. Key retinal pathologies - vitreo-retinal interface

20. Artefacts in OCT imaging
Image of good quality
Out of focus
Vignetted image
Fixation error

21. Kwalitative measurements
─ Retinal thickness measurement
─ Retinal nerve fiber layer thickness
─ Optic nerve head analysis

22. New developments - Anterior segment OCT
Myopia claw lens
Arows = epithelialized drainage
channels
Arrowheads = non-epithelialized
drainage slits
E = conjunctival epithelium
L = lamina propria conjunctivae
T = tenons layer
S = sclera

23. New developments - Spectral (Fourier) Domain Analysis

24. New developments - Heidelbergs Spectralis
Geographic atrophy and drusen
Infrared and OCT
Occult CNV with PED
Fluorescein angiography and OCT
Dry AMD
Autofluorescence and OCT

25. New developments - Zeiss Cirrus

26. New developments - Zeiss Cirrus

27. The End