1. Forewarned is forearmed A retinal update Peter Simcock & Hirut von Lany
OCT interpretation
What not to do with multifocal lenses
An audit of WEEU retinal referrals – when to refer and what to refer 1

2. OCT interpretation

3. A bit of confusing anatomy3

4. Anatomy made simple Neuro-retina Potential sub-retinal space
Retinal Pigment epithelium
Choroid 4

5. Neuro-retina Nerve fibre layer Ganglion cells Bipolar cells
1.1 million fibres per eye
Ganglion cells
Bipolar cells
Rods and Cones (photoreceptors)
Convert light into electrical impulses to transmit to the brain
Most energy dependent tissue in body 5

6. Retinal pigment epithelium
Recycles material from rods and cones
Recycling needed to maintain efficient function
Contains pigment to stop internal reflections
Prevents “glare” inside the eye
Melanin pigment
Pumps water out of the neuro-retina and potential sub-retinal space to keep it “dry” 6

7. Choroid Supply oxygen and glucose to photoreceptors and RPE
Highest blood flow per unit area of any tissue in the body
Look what happens when you faint
Retina is always working very hard! 7

8. Important terminology
Inner retina
Nerve fibre layer
Ganglion cells
Bipolar cells
Supplied by Central retinal artery
Outer retina
RPE and photoreceptors
Supplied by Choroid 8

9. RPE and photoreceptors must not part company – they act as a single unit9

10. Principles of the OCT Non invasive Based on interferometry
Interference between incident and reflected light
Like doing a vertical biopsy of the retina
Use laser light rather than knife!
Good at showing swelling due to leakage
FFA still needed for showing blockage of blood vessels 10

11. Optical coherence tomography Normal anatomy11

12. Retina pathology often in layers
Inner retina (retinal circulation)
Diabetic retinopathy
Retinal vein occlusion
Outer retina (choroidal circulation)
AMD
CSR

13. OCT pathology often in layers
Retinal surface (mechanical problems)
Vitreo-macular traction
Epiretinal membrane
Inner retina (retinal circulation)
Diabetic retinopathy
Retinal vein occlusion
Outer retina (choroidal circulation)
AMD
CSR

14. Retinal pathology in more than one layer
Full thickness macular hole
All layers involved
Lamellar hole
Usually surface and inner retina
Severe retinal disease
Wet AMD (starts in outer retina)
Diabetic eye disease (starts in inner retina)
Retinal vein occlusions (starts in inner retina)

15. Central macular thickness
Normal thickness = 200 microns
Thick retina > 250 microns
Usually due to leakage
Thin retina < 150 microns
Atrophic with poor function
Can be difficult to assess function on thickness alone

16. The Ellipsoid Junction between inner and outer segments
Barely visible in histological sections
Highly prominent with OCT
Due to difference in index of refraction of the inner and outer segments
Also called the photoreceptor integrity line
Used to be called the IS/ OS junction

17. Assess retinal function
Normal thickness retina – how is it functioning?
Well demarcated IS/OS junction suggest good photoreceptor function

18. Vitreo-macular traction
Terminology
Vitreo-retina adhesion – attached but not pulling
Vitreo-macular traction – attached and pulling)
If incidental OCT finding and patient asymptomatic – do not refer

19. Mild Vitreo-macular traction
Inner retinal cyst
0.12 LogMAR

20. Severe Vitreo-macular traction
0.5 LogMAR
“Pointed - being Pulled”

21. Epiretinal membrane Posterior vitreous usually detached
Sometimes associated with lamellar hole
Wide range of severity
If incidental OCT finding and patient asymptomatic – do not refer

22. Mild epiretinal membrane
0.1 LogMAR
Loss of foveal pit

23. Epiretinal membrane 23

24. ERM with saw tooth sign Note healthy ellipsoid Visual acuity is 0.12
No symptoms

25. ERM with lamellar macular hole
Note healthy ellipsoid
Visual acuity is 0.12
No symptoms

26. Full thickness macular hole

27. Spontaneous improvement in a full thickness macular hole

28. OCT and dry AMD
Drusen
“Lumpy bumpy” RPE

29. OCT and dry AMD
RPE atrophy
High signal beneath RPE
Thin retina

30. Wet AMD
Abnormal blood vessels grow upwards from Choroid into Retina (Choroidal neovascular membrane)
May remain under the RPE “Occult”
May grow through RPE into neuro-retina “Classic” 30

31. Occult CNV
retina
RPE
choroid 31

32. Classic CNV
Choroid
Retina
RPE 32

33. Classic CNV – “ring of fire”33

34. Damage to vision Classic Occult
Disrupts RPE / photoreceptor partnership
More aggressive process
Significant and rapid visual loss
Occult
RPE / photoreceptor partnership remains intact
May maintain better vision “low grade occult” 34

35. OCT and wet AMD Outer retina first involved (choroidal circulation)
Fluid
Sub RPE
Sub Retinal
Intra retinal if severe
Usually previous dry AMD
Look at RPE line as rarely “pristine”

36. OCT and wet AMD Sub RPE fluid Sub retinal fluid Intra retinal fluid
Note previous dry changes

37. “Burnt out” Wet AMD
Disciform Scarring

38. What is RAP?
Choroidal neovascular membrane (CNV) are abnormal blood vessels growing upwards from Choroid into Retina (Occult and Classic)
Retinal angiomatous proliferations (RAP) are abnormal blood vessels growing downwards from Retina into Choroid
15% of wet AMD is RAP and 100% bilateral within 3 years 38

39. RAP Multiple intraretinal haemorrhages at macular
Can look like macular branch retinal vein occlusion but does not stop at horizontal midline 39

40. 40

41. OCT and leakage Wet AMD Diabetic maculopathy Retinal vein occlusions
CSR
Uveitis
Retinitis pigmentosa 41

42. Intraretinal fluid 42

43. Sub-retinal fluid 43

44. Sub-RPE fluid (PED) 44

45. Do not forget to look for retinal thickening
Interstitial fluid present
No discrete accumulations of fluid
Still an important sign of leakage 45

46. Do not forget to look for outer retinal hyper-reflectivity
Lipofuscin deposition
Active CNV tissue
Scarring
Look for other OCT and clinical signs to help determine what it is. 46

47. OCT and exudative diabetic maculopathy
Inner retina first involved (retinal circulation)
Fluid
Intra retinal (including cystoid oedema)
Sub retinal if severe
No Sub RPE fluid
Hard exudates
Highly reflective intraretinal spots
RPE looks ok

48. OCT and exudative diabetic maculopathy

49. OCT and retinal vein occlusions
Inner retina first involved (retinal circulation)
Fluid
Intra retinal (including cystoid oedema)
Sub retinal if severe
No Sub RPE fluid
Hard exudates
Less frequently seen than in diabetics
RPE looks ok

50. Ozurdex in macular oedema from central vein occlusion
0.5 LogMAR
Pre injection
0.3 LogMAR
Post injection

51. What is most disruptive to vision?
SEVERE Outer retina (choroidal circulation)
“Classic” wet AMD
MODERATE Inner retina (retinal circulation)
Diabetic oedema
Retinal vein occlusions
MILD Sub-RPE
Low grade “occult” CNV
Chronic PED’s 51

52. Ask yourself Anything on the surface?
Is it mainly inner or outer retina or both?
How does the RPE look?
How well demarcated is the ellipsoid line?
Is there diffuse thickening without focal accumulation of fluid?
Is there retinal thinning?

53. Small BRVO or wet AMD at macula?
Inner retina
RPE normal
Ellipsoid may be preserved
Haemorrhage does not pass across the horizontal midline
Wet AMD
Outer retina
RPE abnormal
Ellipsoid disrupted
Haemorrhage may be on either side of horizontal midline

54. What is this? 54

55. OCT and CSR Leakage from choroid through RPE Fluid RPE Sub Retinal
May be small PED
Remaining RPE looks healthy

56. OCT and CSR

57. Uveitis 57

58. Retinitis pigmentosa Post injection Pre – Sub Tenon’s steroid
Note thin retina
No ellipsoid line
Pre – Sub Tenon’s steroid
“Bell shape – from Below” 58

59. What is this?

60. Adult vitelliform dystrophy
0.0 LogMAR OD
Intact ellipsoid line

61. What is this and what is the vision?

62. Macula schisis 0.0 LogMAR Intact ellipsoid line 0.1 LogMAR

63. What is this?

64. What is this? 64

65. Ruptured retinal macroaneurysm65

66. What is this?

67. It was due to this !

68. Powerpoint presentation
Available on line
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