2. What we will cover
• How OCT works
• Layers of the retina
• 3D OCT Tips
• Healthy retina architecture
• Pathology
• Q&A
3. Seeing better with OCT
Light passing through
tissue is delayed
before it is reflected
back to the
camera
Measurement of this
‘delay’ provides
cross-sectional
information about the
structure of the tissue
being imaged
OCT is able to see the intricate and delicate layers of the
retina, optic nerve and other ocular tissues (e.g. the RPE).
8. • Trade off of scanning
area vs. image quality
• Typical Pre sets
– 8.2 mm x 3 mm @ 1,024 x
32 b scans (better image)
– 6 mm x 6 mm box @ 512
x 128 b scans (better
coverage)
Scanning Protocol
9. Patient preparation
• Pupil size
– Min pupil size is 3.7 mm
– Slightly dilated pupils will improve OCT and fundus image
quality
• Dry cornea
– A dry cornea will reduce the OCT image quality
– Make sure that your technicians tell the patient to blink
before the capture procedure
– Use drops if needed
• Fixation
10. Viewing Techniques
• View in Black and White
to provide better
contrast
• Use OCT image
adjustment bar
16. Pathology
• Reported incidence of pathology detected with
Topcon 3D OCT in a Lasik population during pre-
treatment evaluation was 1.6%
• Typical pathologies
– Epiretinal membrane
– Drusen
– Macular Edema
– Hard Exudates
– Macular Holes
– Vitromacular Traction
17. Epiretinal Membrane
• Incidence is 6% of patients over 60 yrs*.
• Appearance
– Rippling of ILM which can extend over the fovea resulting
of the loss of the normal foveal contour.
*Source: Optical Coherence Tomography of Ocular Diseases,
Schuman, JA, et al, 2004
22. Drusen
• Reported incidence of drusen in patients 43 to 54
was 2.2% (soft) and 3.3% (large)*
• Appearance
– Localized highly reflective area under Bruch’s membrane,
you may also see a slight flattening of the foveal contour.
*Source: Beaver Dam Eye Study
Ophthalmology. 2003 Oct: 109 (10): 1767-79.
27. Macular Edema
• Appearance
– Hypo echoic areas in the retina. Can be associated with
Diabetes (Diabetic Macular Edema- DME), cystic in
appearance (Cystoid Macular Edema- CME)
30. Hard Exudates
• Can be seen in any conditions that are associated
with vascular leakage
– Diabetic retinopathy
– Hypertensive retinopathy
• Appearance
– Focal hyper echoic areas in the ONL
32. Macular Holes
• Extremely rare in patients under except you can see
in the case of trauma. Various types
– Lamellar (partial macular hole)
– Full thickness macular hole
• Appearance
– Lamellar hole- pit/opening from ILM but not down to the RPE
– Full thickness macular hole- Opening down to the RPE, volcano
appeareance
