spectralis oct normal anatomy & systematic interpretation

Interpretation and Terminology

of OCT for Retina

Christopher Mody Clinical

Programme Manager

Heidelberg Engineering Ltd

Make valued judgements whilst scanning

Utilise the fundus reference image

Understand the significance OCT image

Identify pathology & link to visual

symptoms

30° high resolution line scan

Fovea

Inf

Dark regions :

• Intra retinal fluid

• Sub retinal fluid

• Sub RPE fluid

• Retinal elevation

IR fundus reference image

Green areas :

• Intra retinal fluid

• Sub retinal fluid

• Sub RPE fluid

• Retinal elevation

MultiColor fundus reference image

Blue laser FAF reference image

Dark regions:

• Retinal atrophy

• RPE atrophy

Bright regions:

• Active disease

Normal OCT

What does the SD-OCT image actually

represent?

N T

Fovea

Internal Limiting Membrane

Retinal Blood Vessels

RNFL

Ganglion Cell Layer

Inner Plexiform Layer

Inner Nuclear Layer

Outer Plexiform Layer

Outer Nuclear Layer

External Limiting Membrane

Henle fibre layer

Choroid

Inner photoreceptor segments

Inner/outer photoreceptor junction

Rod/cone outer segments

RPE interdigitation

Bruch’s/RPE Complex

Pre-Euretina Normal OCT Classification

Formed Vitreous Posterior Cortical Vitreous

Preretinal Space

Nerve Fiber Layer

Ganglion Cell Layer

Inner Plexiform Layer Inner Nuclear Layer

Outer Plexiform Layer (dendritic)

Henle’s-ONL

junction (subtle)

Henle Fiber Layer (axonal OPL) Outer Nuclear Layer

Sattler’s Layer (inner Choroid)

Haller’s Layer (Outer Choroid)

External Limiting Membrane

Ellipsoid Zone

Outer Segments

Interdigitation Zone

Choriocapillaris

RPE/ Bruch’s

Complex

Myoid Zone

Choroid

Sclera

Junction

Rods & Cones

OS EZ

MZ

ELM

ONL

OPL

IZ

RPE

Inner segment

Ellipsoid zone

Mitochondria

ATP production – chemical energy

Myoid zone

Golgi apparatus

Protein synthesis

Ellipsoid zone

Myoid zone

Evaluating OCT images

1. Determine scan quality

2. Rate overall scan profile

3. Evaluate foveal profile

4. Identify foveal cut

5. Carry out structured assessment

Observe alteration of layers

Identify additional structures

Pre retinal

Epiretinal

Intraretinal

Subretinal

Sub RPE

STEP 1

Determine overall scan quality

Scan quality

Qualitative assessment


Step 1

Scan quality

Identify inner and outer retinal band

Good signal to noise ratio

Truncated

Shadowing

Vitreous opacities

Vessel shadowing

STEP 2

Rate the overall scan profile


Step 2. Rate the over-all retinal scan profile

The normal over-all retinal profile has a slightly

concave curvature.

Abnormal profiles would include exaggerated

concavity and convexity or retinal folds.

The over-all retinal profile

RPE detachment

Fibrotic/Serous

Haemorrhagic

Retinal detachment

Rhegmatogenous

Serous

Retinal thickening

CSMO/CMO/CNV

STEP 3

Evaluate the foveal profile


Step 3. Evaluate the foveal profile

The normal foveal profile is a slight

depression in the surface of the retina.

Foveal profile

Deformations in the foveal profile include the following:

1. Macular pucker

2. Macular pseudo-hole

3. Macular lamellar hole

4. Macular cyst

5. Macular hole, stage 1 (no depression, cyst present)

6. Macular hole, stage 2 (partial rupture of retina, increased thickness)

7. Macular hole, stage 3 (hole extends to RPE, increased thickness, some fluid)

8. Macular hole, stage 4 (complete hole, oedema at margins, complete PVD)

STEP 4

Identify foveal cut

Fovea Do you have a foveal cut?

STEP 5

Carry out a structural assessment

Qualitative Assessment

Step 5. Carry out a structural assessment

a) Observe alteration of layers

b) Identify additional structures

• Pre-retinal

• Epiretinal

• Intra-retinal

• Sub-retinal

• Sub RPE


Pre-retinal

Epiretintal

Intra-retinal

Sub-retinal • Sub neurosensory retina

• Sub RPE


Pre retinal – vitreous cavity:

1. pre-retinal membrane

2. epi-retinal membrane

3. vitreo-retinal strands

4. vitreo-retinal traction

5. syneresis

6. pre-retinal neovascular membrane NVE

7. pre-papillary neovascular membrane NVD


Pre-retinal

A normal pre-retinal profile is displayed as

a black or white space.

Prepapilla/prefoveal lacunae (premacula

bursa) may be visible


Intra-retinal changes:

1. Choroidal neovascularization

2. Diffuse intra-retinal oedema

3. Cystoid macular oedema

4. Hard exudates

5. Scar tissue

6. Atrophic degeneration


Sub-retinal/RPE:

1. choroidal neovascularization

2. RPE detachment

3. Drusen

4. sub-retinal fibrosis

5. scar tissue

6. RPE atrophy

What to look for… 1. Determine scan quality

2. Rate overall scan profile

3. Evaluate foveal profile

4. Identify foveal cut

5. Carry out structured assessment

Observe alteration of layers

Identify additional structures

Pre retinal

Epiretinal

Intraretinal

Subretinal

Sub RPE

TERMINOLOGY

Irregularity

Fragmentation

Rupture

Interruption

Depression

Elevation

Thinning

Thickening

Alteration of Layers

Terminology

Irregularity

Fragmentation

Rupture

Interruption

Depression

Elevation

Thinning

Thickening

RPE

Terminology

Additional Structures

Macular Hole

Epiretinal Membrane (ERM)

Drusen

Blood Component

Fluid /Edema

Non Exudative Spaces

Neovascularisation

Fibrosis

Lipid Precipitates

Hyperreflective Spots & Dense Areas

Tubulations of Outer Retina

Tumours

Identify RPE Examine

RPE

Examine posterior to

RPE

Examine anterior to

RPE

Systematic Procedure

RPE

• Irregularity

• Fragmentation

• Rupture

• Interruption

• Depression

• Elevation

• Thinning

• Thickening

Posterior to RPE

• PED

• Bruch’s Membrane

• Hyperreflectivity (atrophy of RPE vs. fibrosis)

• Hyporeflectivity (screen effect)

Anterior to RPE

• Vitreous

• Retinal Thickness

• Foveal Depression

• Subretinal Fluid

• ELM

• Elipsoid Zone

• Hyperreflective Spots

• Dense Areas

• Outer Nuclear Layer

• Intraretinal Cysts

• Inner Retinal Layers

Identify RPE Systematic Procedure

Examine RPE

One single elevation of RPE (PED)

Undulating (wavy) PED

No interruption

No thickening or thinning of RPE

Identify EPR


RPE

Examine posterior to

RPE

Sub-RPE Reflectivity moderate

Shadow at RPE / sub - RPE

Hyperreflective Zone in inner layers

Intraretinal Cysts (in 2 layers)

Increased retinal thickness

Large Hyperreflective Precipitates

Hyperreflective Punctiform Precipitates

Dense Areas anterior to RPE

Interruption of ELM & Elipsoid Zone


RPE

Retinal Angiomatous Profliferation

(RAP)

Posteriorto RPE

Examine anterior to

RPE

Intra & subretinal fluid

Final thoughts…

Know your chorio retinal anatomy

Familiarise yourself with normal variation in OCT

recordings

Adopt a systematic approach to evaluating OCT images

Familiarise yourself with the aetiology of macular

disease

Don’t forget vision, signs/symptoms, history and fundus

appearance

Questions…

Acknowledgements:

Evangelos Tsiroukis MD

Institut Català de Retina

Barcelona

Professor Yit Yang

Wolverhampton Eye

Infirmary

spectralis oct normal anatomy & systematic interpretation

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