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OPHTHALMOLOGY DEPARTEMENT OF SRIWIJAYA UNIVERSITYM. HOESIN HOSPITAL PALEMBANG

2014

dr. Ristania

Consultant

dr. H.A.K Ansyori,Spm. Mkes.dr. Ramzi Amin, SpM.

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ElectroretinogramLiterature reviewTuesday, Mei 30th 2014

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Background

Holmgren (1865)Karpe (1947)

Research and diagnostic of retinalDiseases Record the Electroretino-graphy

ERG

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Aim

To explain the function of ERG

and how it use for the diagnosis

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Electroretinogram (ERG)

the Record of retinal actioncurrents produce by theretina response to light

stimulus.

measure the electrical responseof the light sensitive cells such as

rods & cones

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ERG Machine

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Physiological Basis

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Human Eye

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The Structure of Retina

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Photoreceptors

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Distribution of Rods and cones

The eye contains about 6.5 million cones and120 million rods.The density of the cones is greatest at the

fovea

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Processing of signal in retina

LightTransduction

Signal processingConvergen and

divergen

OutputGanglioncell, FireSpikes

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Wave Origin

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The Electroretinogram

The a wave is produceddue to photoreceptoractivity.

The b wave originates dueto retinal inner nuclearlayer, from Bipolar &Muller cells.

The c wave is produced bypigmented epithelial cells.

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Recording and Interpretation ERG

The ISCEV Standard species ve responses

(1) Dark-adapted 0.01 ERG(2) Dark-adapted 3.0 ERG(3) Dark-adapted 3.0

(4) Light-adapted 3.0 ERG(5) Light-adapted 3.0 icker

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Recording and Interpretation ERG

Pre Adaptation of Dark

Dark Adapted 0,01 ERG

(Rod Response)

Dark Adapted 3,0 ERG

(Combine Rod-Cone Response)

Dark Adapted 3,0

Oscillatory potentials

Pre Adaptation of Light

Light Adapted 3,0 ERG

(Single Flash Cone Response)

Light Adapted 3,0 Flicker ERG

(30 Hz Flicker)

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Dark-adapted 0.01 ERG(rod response)

The Dark-adapted 0.01 ERG isnormally the rst signal measuredafter dark adaptation

The stimulus is a dim white ash of0.01 cd.s.m -2; with a minimuminterval of 2 s between ashes.

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Dark-adapted 3.0 ERG (combined rod cone response)

This is produced by a white 3.0 cd.s.m -2 ashin the dark-adapted eye. There should be aninterval of at least 10 s between stimuli.

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Dark-adapted 3.0 oscillatory potentials

Dark-adapted oscillatory potentials should beobtained from the dark-adapted eye, usingthe 3.0 cd.s.m -2 flash stimulus.

The high-pass filter must be set at 75 100 Hz,and the low pass filter set at 300 Hz or above.

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Light-adapted 3.0 ERG(single-flash cone response)

Use a 3.0-cd.s.m -2 stimulus, withat least 0.5 s between flashes.

To achieve stable andreproducible cone ERGs, aminimum of 10 min light

adaptation is required,

The background luminance should

be 30 cd.m-2

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Light-adapted 3.0 flicker ERG (30 Hzflicker)

Flicker ERGs also reflect activity of the conesystem, and should be obtained with 3.0-cdsm -2 stimuli,

Flashes should be presented at a rate ofapproximately 30 stimuli per second (30 Hz),and the rate that is chosen should be constant

for the laboratory.

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Interpretation eletroretinography

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Abnormal ERG

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Abnormal ERG

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ERG Function

Retinitis pigmentosa choroideremia, gyrate atrophy of the retina, Goldman-Favre syndrome, congenital stationary night blindness X-linked juvenile retinoschisis Achromatopsia cone dystrophies Usher syndrome

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Multifocal Electro retinography(mfERG)

Recording of multiple spatially resolved ERG

responses from the retina over a central areaof abt 25 degrees.

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Multifocal Electro retinography(mfERG)

The stimulus consists ofan array of 61/102/241hexagonal elements of

black &white color

Multifocal Electro retinography

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Multifocal Electro retinography(mfERG)

N1 response offbipolar cells. P1response on bipolarpeak. N2 response onbipolar cells recovery.

Multifocal Electro retinography

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Multifocal Electro retinography(mfERG)

Clinical application of mfERG It can point outlocal alterations which cannot be detected bystandard ERG.

Excluding outer retinal diseases.Maculopathies.

Vascular disorders. Following disease progression.

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