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1. OPTICAL COHERENCE
TOMOGRAPHY
-MOHAMED ISMAIL
(B.OPTOM)
AN-NOOR EYE HOSPITAL

2. WHAT IS THE PRINCIPLE OF OCT

3. WHAT ARE ALL THE PARAMETERS WE WILL
LOOK FOR IN OCT

4. WHAT IS THE CLINICAL DIAGNOSIS?

5. WHAT IS THE CLINICAL DIAGNOSIS?

6. CAN YOU GUESS?

7. INTRODUCTION
• OPTICAL – LIGHT
• COHERENCE – LIGHT OF A CONSTANT PHASE DIFFERENCE
• TOMOGRAPHY – IMAGING BY SECTIONS
OPTICAL COHERENCE TOMOGRAPHY (OCT) IS AN EMERGING TECHNOLOGY FOR
PERFORMING HIGH-RESOLUTION CROSS-SECTIONAL IMAGING. IT USES INFRA
RED LIGHT RAYS INSTEAD OF SOUND. OCT CAN PROVIDE CROSS-SECTIONAL
IMAGES OF TISSUE STRUCTURE ON THE MICRON SCALE

8. • AXIAL RESOLUTION- 3-20 MICROMETERS
• USING INFRA RED WAVES OF WAVELENGTH 830 NM
• 78D INTERNAL LENS
• NON- INVASIVE

9. HISTORY
• 2002 - TD OCT
- 400-512 A SCANS/SEC
- ALONG WITH THIS AS OCT INTRODUCED
• 2004 – SD OCT(CONCEPT)
• 2007 – SD OCT
- 20K – 52K A SCANS/ SEC
- DEVELOPMENT OF SS OCT TECHNOLOGY
- 370K A-SCANS PER SEC
• 2014- FIRST COMMERCIAL OCT ANGIOGRAPHY DEVICE INTRODUCED

10. PRINCIPLE

11. INTERFEROMETRY
• WHEN TWO WAVES OF LIGHT TRAVEL ALONG THE SAME PATH, THE EFFECT
PRODUCED DEPEND UPON WHETHER OR NOT THE WAVES ARE IN PHASE OR OUT
OF PHASE WITH ONE ANOTHER

12. PARTS

14. WORKING
• LIGHT FROM REFERENCE AREA AND SAMPLE AREA COMBINED
• DIVISION OF THE SIGNAL BY WAVELENGTH
• ANALYSIS OF WAVELENGTH
• INTERFENCE PATTERN
• A-SCAN CREATED FOR EACH POINT
• B-SCAN CREATED BY COMBINING A-SCANS

15. 1. DIGITAL PROCESSING
2. DIGITAL SMOOTHING
• COLOUR CODING
Hyper reflective- Red Moderate Reflective-
Green to yellow
Hypo Reflective- Blue
to Black
ILM
RNFL
OPL, ELM, EZ
RPE- Choriocapillaries
complex
Inner Plexiform Layer GCL
INL
ONL

16. ADVANTAGES
• QUICK AND NON-INVASIVE
• NON-CONTACT
• REPRODUCABLE
• MINIMAL CO-OPERATION
• RESOLUTION -10 MICRONS
• EARLIEST SIGNS
• QUANTITATIVELY MONITOR DISEASE/ STAGING

17. DISADVANTAGES
• BEST FOR ONLY OPTICALLY TRANSPARENT TISSUES
• DIMINISHED PENETRATION THROUGH RETINAL OR SUB RETINAL HAEMORRHAGE
• REQUIRES PUPIL DIAMETER GREATER THAN 3 MM

19. TYPES OF SCAN DONE IN OCT
1. OCT MACULA
2. OCT DISC AND RNFL ANALYSIS
3. AS-OCT
4. OCTA

20. OCT MACULA
• 3D SCAN
• RADIAL SCAN
• RASTER SCAN
• MACULAR CUBE
a)3D scan b) Radial scan c)Raster Scan

22. RETINA

23. ADDITIONA
L
STRUCTURE
S
EPI RETINAL
MEMBRANE
HYPER
REFLECTIVE
SPOTS AND
DENSE
LIPID
PRECIPITATES
NEOVASCULARIZ
ATION
FLUID/ EDEMA
DRUSEN

24. IDENTIFY RPE
EXAMINE ANTERIOR
TO RPE
EXAMINE POSTERIOR
TO RPE
EXAMINE RPE

25. IDENTIFY ADDITIONAL STRUCTURES
• PRE- RETINAL
• EPI- RETINAL
• INTRA- RETINAL
• SUB- RETINAL
• SUB RPE

26. QUALITATIVE ANALYSIS
• MORPHOLOGICAL CHANGES
• REFLECTIVITY
• SHADOWING
• STRUCTURE

27. TERMINOLOGY- RPE ALTERATION
• IRREGULARITY
• FRAGMENTATION
• RUPTURE
• INTERRUPTION
• DEPRESSION
• ELEVATION
• THINNING
• THICKENING

28. QUALITATIVE ASSESSMENT
• PRE RETINAL- VITREOUS CAVITY:-
1. EPI- RETINAL MEMBRANE
2. VITREORETINAL TRACTION
• INTRA RETINAL CHANGES
1. CME
2. CNV
3. HARD EXUDATES
4. INTRA RETINAL HAEMORRHAGES
Vitreoretinal traction
ERM

29. • SUB RETINAL/ RPE
1. CNV
2. PED
3. DRUSEN
4. RPE ATROPHY
5. SUB RETINAL HAEMORRHAGES
6. SCAR TISSUE

30. MICRO ANEURYSM
•SMALL OUTPOUCHINGS OF MACULAR
CAPILLARY BED
RPE BREAK

31. • DISCIFORM SCAR

32. FOVEAL PROFILE
• MACULAR PUCKER
• MACULAR PSEUDO HOLE
• MACULAR LAMELLAR HOLE
• MACULAR CYST
• MACULAR HOLE

33. DISEASES OF MACULA
• FULL THICKNESS MACULAR HOLE
• CYSTOID MACULAR EDEMA
• ARMD
• CENTRAL SEROUS CHORIORETINOPATHY

34. MACULAR HOLE
• 0- PERIFOVEOLAR DETACHMENT
• 1A- IMPENDING MACULAR HOLE
• 1B- OCCULT MACULAR HOLE
• 2- EARLY FTMH(PARTIAL OPENING OF
THE ROOF OF THE CYST)
• 3- ESTABLISHED FTMH
• 4- FTMH WITH PVD

36. DIFFERENCE BETWEEN LAMELLAR AND
PSEUDO HOLE
LAMELLAR MACULAR HOLE
• INTRA RETINAL SPLIT WITH
SEPARATION OF THE INNER
AND OUTER FOVEAL RETINAL
LAYERS
• ABSENCE OF A FULL
THICKNESS FOVEAL DEFECT
PSEUDO HOLE
• AN APPEARANCE OF THE THE
RETINA DUE TO
CONTRACTION FROM THE
ERM

37. CYSTOID MACULAR EDEMA
• CAUSES
1. OCULAR SURGERY AND LASER
2. RETINAL VASCULAR DISEASE
3. INFLAMMATION
4. DRUG INDUCED(NIACIN, GILENYA)
5. RETINAL DYSTROPHIES
6. CONDITION HAVING VMT; ERM
7. CNV
8. TUMOUR
9. CHRONIC RENAL FAILURE

38. CLINICAL FEATURES
• RETINA CONSISTING OF FLUID ACCUMULATION IN THE OPL OF CENTRAL MACULA
• FORMATION OF VISIBLE CYSTIC SPACES

39. EXAMPLES

40. COMBINED CRVO
WITH SECONDARY
BRAO

41. CENTRAL SEROUS RETINOPATHY
• MAYBE ASSOCIATED WITH PED
• PROLONGED SEPARATION OF NEURO RETINA FROM THE RETINAL PIGMENTED
EPITHELIUM
• PATIENT MAY PRESENT AS BULLOUS
INFERIOR PERIPHERAL RETINAL
DETACHMENT(NON-RHEGMATOGENOUS)

42. • OCT MAY REVEALS SRF, PED, RETINAL ATROPHY
FOLLOWING CHRONIC DISEASE
• NEUROSENSORY AND MACULAR DETACHMENTS
• ALSO HELPFUL IN IDENTIFYING THE DREADFUL
COMPLICATION OF CHOROIDAL NEO VASCULAR
MEMBRANE

43. AGE RELATED MACULAR DEGENERATION
• LOSE OF VISION IN THE CENTER OF THE VISUAL FIELD
• MEDIUM AND LARGE SIZED DRUSEN
• DRUSEN
I. EXTRA CELLULAR DEPOSITS
TYPES
• WET
• DRY

44. DRY AGE RELATED MACULAR DEGENERATION
VS WET AMD

46. PARA-FOVEAL TELENGECTASIA

47. RETINAL DETACHMENT

48. TRACTIONAL RETINAL DETACHMENT
RETINOSCHISI
S

49. RD WITH RETINOSCHISIS

52. RETINITIS PIGMENTOSA

53. MYOPIA
• STAPHYLOMAS
• MYOPIC CNVM
• MYOPIC SCARS
• MYOPIC FOVEOSCHISIS
• MACULAR HOLE AND LAMELLAR HOLE
• ERM

54. Myopic
foveoschisis
Myopic Traction
Maculopathy(MT
M)

55. QUALITATIVE ANALYSIS
• RETINAL MAP
• RETINAL THICKNESS
• RETINAL VOLUME

56. NORMATIVE DATA FOR RETINAL LAYER
THICKNESS

57. RETINAL THICKNESS IN CME

59. RNFL AND OCT
DISC
1. CHECK THE SIGNAL STRENGTH
2. RNFL THICKNESS MAP
3. RNFL DEVIATION MAP
4. RNFL GRAPH
5. NRR THICKNESS
6. HORIZONDAL ND VERTICAL EXTRACTED TOMOGRAMS
7. RNFL THICKNESS QUADRANTS
8. RNFL CIRCULAR TOMOGRAM

61. ANTERIOR SEGMENT OCT
• CROSS SECTIONAL IMAGING OF
1. CORNEA
2. ANTERIOR CHAMBER
3. ANGLE OF ANTERIOR CHAMBER
4. IRIS
• USING HIGHER WAVELENGTH OF 1310NM

62. IMAGING MODES OF AS-OCT
• HIGHER RESOLUTION OF CORNEA
• PACHYMETRY
• ANTERIOR SEGMENT (SINGLE, DOUBLE, AND QUAD)

63. ARTIFACTS
• ARTIFACTS CAN OCCUR DURING IMAGE ACQUISITION OR ANALYSIS BECAUSE OF
PATIENT, OPERATOR OR SOFTWARE FACTORS

64. TYPES
• MIRROR ARTIFACTS
• VIGNETTING
• MISALIGNMENT
• SOFTWARE BREAKDOWN
• BLINK ARTIFACT
• MOTION ARTIFACT
• OUT OF RANGE ERROR

65. MIRROR ARTIFACT
• AREA OF INTEREST CROSSES THE ZERO DELAY LINE

66. VIGNETTING
• WHEN IRIS BLOCKS A PART OF OCT BEAM

67. MISALIGNMENT
• WHEN FOVEA IS NOT CENTERED

68. SOFTWARE BREAKDOWN
• OCT SEGMENTATION LINES ARE INCORRECT BCOZ OF MIS IDENTIFICATION OF
THE INNER OR OUTER RETINAL BOUNDARIES

69. BLINK ARTIFACT
• DURING IMAGE AQUISITION

70. MOTION ARTIFACT
• DISTORTION OR DOUBLE SCANNING
• BLOOD VESSELS ARE MISALIGNED
• FOVEA MIGHT BE DUPLICATED

71. OUT OF RANGE ERROR
• DUE TO IMPROPER POSITIONING OF THE MACHINE DURING IMAGE ACQUISITION

72. RECENT ADVANCEMENTS
• ULTRA HIGH RESOLUTION OCT
• DOPPLER OCT
• CAS OCT-VISANTE OCT
• COMBINED FFA AND EN-FACE OCT
• INTRAOPERATIVE OCT
• OCT ANGIO

73. IMPORTANT POINTS TO NOTE IN OCT
• LOOK OUT THE CLINICAL CONDITION
• LOOK OUT THE RETINAL AND MACULAR PROFILE
• EXAMINE THE QUALITATIVE AND QUANTITATIVE ANALYSIS
• ELIMINATE ARTIFACTS
• ALWAYS CORRELATE WITH CLINICAL FEATURES

74. THANK YOU
ISMAIL_C13