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NEW INSTRUMENTS/CASE DISCUSSION

Speaker M Jayasree

Moderators J Manju

Anju

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Contents• Optical Coherence Tomography

• Microperimetry

• Multifocal Electroretinogram

• Glaucoma Diagnostics

GDx

HRT

GLAUCOMA OCT

HVF

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OCULAR COHERENCE TOMOGRAPHY

PRINCIPLE

•OpticalOptical involves light and optics Used for Optical biopsy of retina.

•CoherenceCoherence – two light beams of same wave length in phase. Uses principle of low coherence interferometry.

•TomographyTomography Tome/Tomo – Greek for section /cutting

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SDOCTSDOCT

Resolution – 6 micronsResolution – 6 microns

Wavelength – 840 nmWavelength – 840 nm

3-D imaging3-D imaging

No movement artifactsNo movement artifacts

25,000 A-scans/second25,000 A-scans/second

Determining and visualizing structure that Determining and visualizing structure that absorb and scatter lightabsorb and scatter light

NoncontactNoncontact

NoninvasiveNoninvasive

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IndicationsIndications•Retinal- macula and Optic nerve.

•Inconclusive FFAs- done together.

•Quantify extent of lesions ex-CNVM, thickness of macula.

•Quantify RNFL thickness around Optic nerve head.

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PHOTORECEPTORSPHOTORECEPTORSRPERPE

CHORIOCAPILLARISCHORIOCAPILLARIS

NFLNFL

FOVEOLAFOVEOLA

GCLGCL

ELM

ONLONL

OPLOPL

INLINLIPLIPL

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Hyper reflectivityHyper reflectivity

Above the NFLAbove the NFL

Posterior Hyaloid ,Epiretinal Membrane,Blood

In the NFLIn the NFL

Inflammation, Cotton Wool Spots, Inflammation, Cotton Wool Spots, Blood Vessels,Blood Vessels,

Flame Shaped HemorrhagesFlame Shaped Hemorrhages

In the nuclear and plexiform layersIn the nuclear and plexiform layers

Hard Exudates, Dot Blot HemorrhagesHard Exudates, Dot Blot HemorrhagesIn the RPE CC layerIn the RPE CC layer

Hyperpigmentation, CNVHyperpigmentation, CNV

In the sub RPE layerIn the sub RPE layer

Drusens, Blood, FibrosisDrusens, Blood, FibrosisIn the choroidsIn the choroids

Scar, TransmissionScar, Transmission

Hypo reflectivityHypo reflectivity

AbsenceAbsence

EdemaEdema

Cystoid spacesCystoid spaces

Fluid – serousFluid – serous

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•NORMAL VITREO RETINAL INTERFACE

•NORMAL FOVEAL CONTOUR WITH FOVEAL DIP

•INNER RETINAL RETINAL LAYERS ARE NORMAL

•NORMAL RPE CC COMPLEX

•FOVEAL THICKNESS

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•NORMAL VITREO RETINAL INTERFACE

•FOVEAL CONTOUR ALTERED

•THICKENED HYPERREFLECTIVE INNER LAYERS

•E/O SRF , SUGGESTIVE OF ACTIVE CNVM WITH CYSTIC SPACES IN THE INNER RETINAL LAYERS

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•THICK ERM NOTED

•ALTERED FOVEAL CONTOUR

•LARGE CNVM, NO E/O SRF SUGGESTIVE OF SCARRED CNVM

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•THIN ERM

•ELEVATED FOVEAL CONTOUR

•THICKENED AND HIGH REFLECTIVE MEMBRANE NOTED SUBFOVEALLY

•NO E/O SRF,SUGGESTIVE OF SCARRED CNVM

•SMALL DRUSENOID PED

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• WRINKLED ILM

•ALTERED FOVEAL CONTOUR

•INNER RETINAL LAYERS ARE THICK AND CYSTIC SPACES

•THICKENED AND HIGH REFLECTIVE RPE-CC COMPLEX WITH MULTIPLE PED

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•NORMAL VITREO RETINAL INTERFACE

•FOVEAL CONTOUR ELEVATED AND THINNED

•HYPER REFLECTIVE INNER LAYES

•CSR

•SEROUS PED

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•NORMAL VITREO RETINAL INTERFACE

•FOVEAL CONTOUR ALTERED

•HEMORRHAGIC PED

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•WRINLED ILM

•FOVEAL CONTOUR ALTERED

•CYSTIC SPACES IN THE INNER RETINAL LAYERS

•SEROUS AND FIBROUS PED

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•INCOMPLETE POSTERIOR VITREOUS DETACHMENT

•FOVEAL CONTOUR ALTERED

•FIBROVASCULAR PED

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•INCOMPLETE POSTERIOR VITREOUS DETACHMENT

•FOVEAL CONTOUR ALTERED

•DRUSENOID PED

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•NORMAL VITREO RETINAL INTERFACE

•FOVEAL CONTOUR ALTERED

•HARD EXUDATES IN THE INNER RETINAL LAYERS

•NORMAL RPE CC COMPLEX

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•NORMAL VITREO RETINAL INTERFACE

•FOVEAL CONTOUR ALTERED

•DIFFUSE HARD EXUDATES IN THE INNER RETINAL LAYERS

•NORMAL RPE CC COMPLEX

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•NORMAL VITREO RETINAL INTERFACE

•CSME CME FOVEOLAR DETACHMENT

•THICKENED HYPER REFLECTIVE CYSTIC SPACED INNER LAYERS

•NORMAL RPE-CC COMPLEX

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•NORMAL VITREO RETNAL INTERFACE

•FOVEAL CONTOUR ELEVATED/THINNING

•NEURO SENSORY DETACHMENT

•SRF, SUGGESTIVE OF CSR

•NORMAL RPE COMPLEX

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•ERM WITH ILM FOLDS

•FOVEAL CONTOUR ALTERED

•INNER RETINAL THICKENED

•NORMAL RPE CC COMPLEX

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•ERM WITH WRINKLING ILM

•LAMELLAR MACULAR HOLE

•THIN INNER RETINAL LAYERS

•NORMAL RPE COMPLEX

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•FULL THICKNESS MACULAR HOLE WITH OPERCULUM

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•COMPLETE POSTERIOR VITREOUS DETACHMENT

•VITREOUS TRACTION RELEASED

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•NORMAL VITREO RETINAL INTERFACE

•FOVEAL SCHISIS

•THINNED CYTIC SPACES INNER LAYERS

•RPE ALTERED

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•FOVEAL CONTOUR ALTERED

•OPTIC DISC PIT

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•OPTIC DISC PIT MACULOPATHY

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•VITREO MACULAR TRACTION

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Case 1

• DATE OF VISIT 22/08/08

• BCVA OS 6/36, N36

• SL OS WNL

• FUNDUS OS CNVM, SUB RETINAL HEAMORRHAGE

•OCT OS E/O SRF , SUGGESTIVE OF ACTIVE CNVM WITH CYSTIC SPACES IN THE INNER RETINAL LAYERS

OS INJ AVASTIN GIVEN THRICE

PRE TREATMENT

POST TREATMENT•DATE OF VISIT 22/11/08

• BCVA OS 6/12, N8

• SL OS WNL

• FUNDUS OS SCARREDCNVM,

•OCT OS NO E/O SRF , SUGGESTIVE OF SCARRED CNVM WITH CYSTIC SPACES IN THE INNER RETINAL LAYERS

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PROGNOSIS HOLE FORM FACTOR

•HFF > 0.9 - 100 % PRIMARY CLOSURE

•HFF = 0.5 - 67 % PRIMARY CLOSURE

•HFF < 0.5 - Poor closure rates

•HIGHER HFF - BETTER POST OP VA

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CASE 2•DATE OF VISIT (25/09/08)

•BCVA OS 6/48(ECC VIEW), N24

•S/L OS NO ABNORMALITY

•FUNDUS OS FTMH

•OCT OS FULL THICKNESS MACULAR HOLE WITH COMPLETE PVD

PRE TREATMENT

S/P VIT+C3F8 UNDER GA POST TREATMENT

•DATE OF VISIT (6/12/08)

•BCVA OS 6/12+, N8

•S/L OS WNL

•FUNDUS OS

•OCT OS

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Multifocal Electroretinogram (mfERG) in Retinal Disorders

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Multifocal electroretinogram

• Simultaneous recording of focal retinal responses

• Offers direct, objective and topographical mapping of central 36-

40º of retinal function

• Cone driven responses

• Fovea, Para fovea and near peripheral photopic retina function can

be evaluated.

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mfERG Stimulus

• Display contains array of hexagons-

• Commonly used 103 hexagonal

array

• Scaling basis - Photoreceptor

density

• Produce local retinal responses of

equal amplitude

• Flickers according to pseudorandom

binary m-sequence

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1.6 °

1.6°- 6°

6°-11.4°

11.4°-18.2°

18.2°-26.2°

26.2°-35°

• Waveforms grouping according to different retinal eccentricities

• Subtends 35° horizontally and 31° vertically – viewing distance 53cm

• The responses obtained from six zones

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MultiplotTrace Array

First order kernel responses- Interpretation

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mfERG Components

• N1 – First negative trough

• P1- First positive Peak

• Origins

Cone Photoreceptors

Dominated by on and off bipolar cells

N1- IT

P1-IT

P1- AMP

N1-AMP

Parameters

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• Degenerative photoreceptor disease

Larger delay in implicit times

• Local lesions damaging INL

Larger reduction in amplitudes

• Damage to NFL or GCL

No reduction or delay

Interpretation

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Clinical applications

• To distinguish retinal diseases from optic nerve disease

• Details extent of lesion

• Sensitive indicator for retinal drug toxicity

• Post-operative management following V-R surgery

• Assess sub-clinical retinal changes in DR

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Case 1

Stargardt’s disease Few yellowish flecks at the macula

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Fullfield ERG

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Multifocal ERG – Trace array

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Multiplot

Crater like defect - MfERG delineates the macular pathology

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Case 2

Cone Dystrophy

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Fullfield ERG

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Multifocal ERG – Trace array

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Multiplot

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Case 3

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Fullfield ERG

Retinitis Pigmentosa

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Multifocal ERG – Trace array

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MultiPlot

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Case 4

JUVENILE RETINOSCHISIS

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Case 5

Fine RPE stippling in normal looking fundus – Chloroquine toxicity

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MICROPERIMETRY

•It is an instrument for fundus related perimetry - assess the central visual field and correlates the findings directly to the fundus location

•Captures patient’s retina and simultaneously projects light stimuli on to the retina

•Stimuli have been projected and the operator customizes the pattern of stimuli according to the retinal disease

•Easily adapted to the different diseases of macula

•Assess also the patient’s fixation site and stability of fixation over time as stable, relatively unstable and unstable

•With or without pupillary dilation (if undilated pupil size min 4mm required)

•Persons who have low vision or fixation problems, the stimulus can be made thicker or larger – also the fixation target may be chosen as either single cross, four crosses or circle, any color , any size

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Comparison with HVFMICROPERIMETRY

• Even a small central, paracenral scotoma

can be detected, understand and assess

macular disease

• Fixation location is assessed

• Direct corelation between threshold values

and retinal sensitivity in decibels

• Operator decides the stimuli location and

time interval between the stimuli

• Gives best results especially in cases of

vitreo retinal surgeries(pre and post),

before and after PDT THERAPHY, easily

detects the defect is in the retina or visual

pathway

HVF

• Macular program available but

relatively small central scotoma

may be missed

• Cannot be assessed

• Similar but logarithmic values in

apostils

• Cannot be done

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Fixation cross, at the macula

Retinal sensitivity in decibels

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Fixation target four crosses

Filled green square better sensitivity

Filled yellow square moderate sensitivity

Filled red square poor retinal sensitivity

Empty square stimulus not seen

MAP REPRESENTATION

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•operator decides when and where to project each stimulus on the tracked retinal image and its corresponding initial intensity in manual micro perimetric exam

•In a semi-automatic exam the operator shall define a polygonal area on the tracked image and the number of stimuli inside the selected area.

•In an automatic exam the stimuli are proposed following a pattern chosen from among the pre-determined or customized by the operator.

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Clinical applications of micro perimetry

• ARMD/AMD(atrophic and neovascular)

• EARLY AMD

• DIABETIC MACULAR EDEMA

• VITREO RETINAL INTERFACE DISORDER

• LOW VISION PATIENT

• MACULAR HOLE CYST

• TOXIC MACULOPATHIES

• CSR

• HEREDITORY RETINAL DYSTROPIES(RP, STARGARDT’S DISEASE,BEST’S

DISEASE)

65Thank You

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PRE POST MICROPERIMETRIC IMAGEYET TO BE PASTED