ERG and VEP Lecture sept 20, 2015
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Transcript of ERG and VEP Lecture sept 20, 2015
ERG and VEP for NEURO-VISUAL FUNCTION ASSESSMENT
J. Alberto Martinez, M.D.
CURRENT REALITY• BY THE TIME WE DIAGNOSE GLAUCOMA, THE
PATIENT HAS HAD IT FOR 5 YEARS! (or more)
“In patients who are glaucoma suspects, PERG signal anticipates an equivalent loss of OCT signal by several years (as many as 8 years).”
Invest Ophthalmol Vis Sci. 2013;54:2346–2352) DOI:10.1167/iovs.12-11026
Per NIH and Bascom-Palmer
ASSESSMENT OF NEURO-VISUAL FUNCTION
Neuro-visual Pathway Function Review1. Anatomy at glance2. Neuro-physiology at glance
Electrophysiology3. Visual Evoked Potential (VEP) concepts4. VEP hardware and software5. VEP obtaining and interpreting6. Other electrophysiological tests\Clinical VEP7. Glaucoma8. MS9. Amblyopia10.Cataract11.Other
Continued
INDEX
VEP and Function Tests1. VA, CS, CV2. VF
VEP and Structure Tests3. HRT, GDxOCTINDEX
PERG4. Basics5. Clinical usage of
PERG6. Retino-cortical
time.Q & A
ASSESSMENT OF NEURO-VISUAL FUNCTION
Eye
Optic Nerve
Optic ChiasmOptic TractLateral Geniculate Nucleus
Optic Radiation
Visual Cortex
ANATOMY
ASSESSMENT OF NEURO-VISUAL FUNCTION
ANATOMY
PhotoreceptorBipolarGanglion
Ganglion cell axon
Relay neuron
Relay neurons axon
Visual cortex neuron
ASSESSMENT OF NEURO-VISUAL FUNCTION
NEURO-PHYSIOLOGY
Phototransduction
Conversion of light into electricity
ASSESSMENT OF NEURO-VISUAL FUNCTION
VEP
Photoreceptor
Ganglion cell axon
Relay neuron
Visual cortex neuron
NEURO-PHYSIOLOGY
Bipolar
Light
Phototransduction
Electricity
Electricity
Electricity
Electricity
ASSESSMENT OF NEURO-VISUAL FUNCTION
ELECTROPHYSIOLOGY
• Electrocardiogram
• Electromyography
• Auditory Evoked
Potential
• Electroencephalogram
ASSESSMENT OF NEURO-VISUAL FUNCTION
Electric signal registered at the
occipital region in response to a
visual stimulus.
ASSESSMENT OF NEURO-VISUAL FUNCTION
VEP
Electrical activity of V1 occipital
cortex
Electric signal registered at the lower
lid in response to a visual stimulus.
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG
Electrical activity of retinal ganglion
cells
ASSESSMENT OF NEURO-VISUAL FUNCTION
Previous Limitations
• Test time was approximately 45
minutes
• Required highly trained operators
• Limited to large research institutions
ASSESSMENT OF NEURO-VISUAL FUNCTION
• Test time is approximately 1
minute
• Does not require highly
trained operators
• Currently installed in about
700 offices worldwide
Current Conditions
VEP Stimulus
• Diffuse
• Pattern
Reversal
Pattern-onset
Transient
Steady State
ASSESSMENT OF NEURO-VISUAL FUNCTION
• Diffuse Pattern
Reversal
Pattern-onset
Contrast
Color
ASSESSMENT OF NEURO-VISUAL FUNCTION
ASSESSMENT OF NEURO-VISUAL FUNCTION
Why would VEP show a functional change on patients with 20/20?
20/20
20/200
20/10020/50
20/30
20/70
20/100
20/10020/25
ASSESSMENT OF NEURO-VISUAL FUNCTION
N75
N135
P100
VEP Components
ASSESSMENT OF NEURO-VISUAL FUNCTION
N75
N135
P100
VEP Components
• Amplitude usually translates to the number of axons conducting along the visual pathway
• Latency usually translates to the myelin status of the visual pathway
Diopsys® VEP Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
Diopsys® VEP Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
Diopsys® VEP Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
Diopsys® VEP Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
Diopsys® VEP Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
Diopsys® VEP Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
Diopsys® VEP Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
Diopsys® VEP Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
Main Indications
• Glaucoma
• Multiple Sclerosis
• Ischemic Optic Neuropathy
• Traumatic Brain Injury
• Amblyopia
• Other Neuropathies
ASSESSMENT OF NEURO-VISUAL FUNCTION
VEP
VEP and other Ophthalmic Diagnostic Tests
• Psychophysics• VF• GDx• HRT• OCT
ASSESSMENT OF NEURO-VISUAL FUNCTION
Psychophysics of vision
Visual Acuity Test
ASSESSMENT OF NEURO-VISUAL FUNCTION
Psychophysics of vision
Contrast Sensitivity Test
ASSESSMENT OF NEURO-VISUAL FUNCTION
Psychophysics of vision
Color Vision Test
ASSESSMENT OF NEURO-VISUAL FUNCTION
Psychophysics of vision
Visual Field Test
ASSESSMENT OF NEURO-VISUAL FUNCTION
ERG mERG pERG mVEP EOG
Electroretinogram Multifocal ElectroretinogramPattern ElectroretinogramMultifocal Visual Evoked PotentialElectrooculogram
Electrophysiological tests
ASSESSMENT OF NEURO-VISUAL FUNCTION
ASSESSMENT OF NEURO-VISUAL FUNCTION
N35
N95
P50
PERG GENERALConcept
Pattern Electroretinography is the electrical signal registered at the eye because of a pattern stimulation of the retina.
ASSESSMENT OF NEURO-VISUAL FUNCTION
Stimulus(Monitor)
Recording(Sensors)
Eye stimulation by a checkerboard pattern elicits a ganglion cell
response known as PERG.
PERG is an accurate and objective indicator of
ganglion cell and macular function.
(ISCEV)
PERG can detect retinal dysfunction (OHT) before
structural tests.(Parisi et al.)
pERG
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG GENERAL
ERG
PERG
Q
24”24.1°
Stimulation Monitor
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG TEST
WRONG
ASSESSMENT OF NEURO-VISUAL FUNCTION
ReproducibilityFactors able to affect the PERG results
• Refraction errors
• IOP
• Diabetes M
• Patient Attention
• Technique
PERG TEST
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG TEST
MonofocalMultifocal
PERG should be done with refractive correction for 24”
Uncorrected
Diopsys® pERG Electrodes
Comfort Convenience Quality
ASSESSMENT OF NEURO-VISUAL FUNCTION
ASSESSMENT OF NEURO-VISUAL FUNCTION
Active for OSReference for OD
Active for ODReference for OS
Ground
Sensors Position
PERG TEST
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG TEST
Active Skin Sensor Placement
Step 1.Sensor positioning.
Eyelashes
Eyelid Skin
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG TEST
Active Skin Sensor Placement
Step 2.Sensor positioning.
Eyelashes
Eyelid Skin
ASSESSMENT OF NEURO-VISUAL FUNCTION
Electrodes Picture Cost ($) Position Amplitude Repeatability Visual Axis Disturbance
Overall Discomfort
Usage
DTL 13 Conjunctiva (invasive)
***** Sensitive to eye movements (noise)
** *** Disposable
HK Loop 35 Conjunctiva (invasive)
***** Sensitive to eye movements (noise)
** *** Reusable
Gold Foil 10 Conjunctiva (invasive)
***** Sensitive to eye movements (noise)
** *** Disposable
Gold Cup 13 Skin *** Good ** ** Reusable
Diopsys 11 Skin *** Good * * Disposable
ELECTRODES COMPARISON
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG TEST
Q
Protocols
1. VEP TR
2. VEP LX
3. PERG Manual
4. PERG Auto
ASSESSMENT OF NEURO-VISUAL FUNCTION
Concentric Fields 24° and 16°PERG TEST
ASSESSMENT OF NEURO-VISUAL FUNCTION
Contrast Sensitivity (higher and lower contrast)PERG TEST
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PERG
Main Indications
• Glaucoma
• Maculopathies
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG CLINIC
Vision problem of unknown cause
VEP
PERG
Differentiating between optic nerve and retinal disorders
Manual
TR
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG Report
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG Report
Magnitude DMagnitude D
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG Report
Grating Size: 64
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG CLINIC
Vision problem of unknown cause
VEP
PERG
Differentiating between optic nerve and retinal disorders
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG CLINIC
Normal
Ischemic
Compressive
Toxic
inflammatory
Glaucoma
Nutritional
Hereditary
Q
ASSESSMENT OF NEURO-VISUAL FUNCTION
Banitt MR, Ventura LM, Feuer WJ, Savatovsky E, Luna G, Shif O, Bosse B, Porciatti V. Progressive loss of retinal
ganglion cell function precedes structural loss by several years in glaucoma suspects. Invest Ophthalmol Vis
Sci. 2013;54:2346-52.
IOP Genetic
Oxidative StressNeurotoxicityHypoxia
ASSESSMENT OF NEURO-VISUAL FUNCTION
Banitt MR, Ventura LM, Feuer WJ, Savatovsky E, Luna G, Shif O, Bosse B, Porciatti V. Progressive loss of retinal
ganglion cell function precedes structural loss by several years in glaucoma suspects. Invest Ophthalmol Vis
Sci. 2013;54:2346-52.
IOP Genetic
Oxidative StressNeurotoxicityHypoxia
ASSESSMENT OF NEURO-VISUAL FUNCTION
Banitt MR, Ventura LM, Feuer WJ, Savatovsky E, Luna G, Shif O, Bosse B, Porciatti V. Progressive loss of retinal
ganglion cell function precedes structural loss by several years in glaucoma suspects. Invest Ophthalmol Vis
Sci. 2013;54:2346-52.
IOP Genetic
Oxidative StressNeurotoxicityHypoxia
ASSESSMENT OF NEURO-VISUAL FUNCTION
Banitt MR, Ventura LM, Feuer WJ, Savatovsky E, Luna G, Shif O, Bosse B, Porciatti V. Progressive loss of retinal
ganglion cell function precedes structural loss by several years in glaucoma suspects. Invest Ophthalmol Vis
Sci. 2013;54:2346-52.
IOP Genetic
Oxidative StressNeurotoxicityHypoxia
ASSESSMENT OF NEURO-VISUAL FUNCTION
Banitt MR, Ventura LM, Feuer WJ, Savatovsky E, Luna G, Shif O, Bosse B, Porciatti V. Progressive loss of retinal
ganglion cell function precedes structural loss by several years in glaucoma suspects. Invest Ophthalmol Vis
Sci. 2013;54:2346-52.
IOP Genetic
Oxidative StressNeurotoxicityHypoxia
/Users/jalbertomartinez/Desktop/Suffering ganglion cells.png
ASSESSMENT OF NEURO-VISUAL FUNCTION
Structure FunctionFundus Photograph
(Subjective)Visual Field(Subjective)
ASSESSMENT OF NEURO-VISUAL FUNCTION
Structure FunctionOptical Coherence Tomography
(Objective)Pattern ERG(Objective)
Healthy
Asymptomatic Symptomatic
VF
Glaucoma
Ellish NJ, Higginbotham EJ. Evaluating a visual field screening test for glaucoma: how the choice of the gold standard affects the validity of the test. Ophthalmic Epidemiol. 2001 Dec;8(5):297-307.
ASSESSMENT OF NEURO-VISUAL FUNCTION
Healthy
Asymptomatic Symptomatic
VF
Glaucoma
OCT
Documented structural damageNon documented structural damage
Schuman JS, Hee MR, Arya AV, Pedut-Kloizman T, Puliafito CA, Fujimoto JG, Swanson EA. Optical coherence tomography: a new tool for glaucoma diagnosis. Curr Opin Ophthalmol. 1995 Apr;6(2):89-95.
ASSESSMENT OF NEURO-VISUAL FUNCTION
Healthy
VF
Glaucoma
OCT
Documented structural damageNon documented structural damage
PERG/VEP
Documented functional damageNon documented functional damage
Parisi V, Miglior S, Manni G, Centofanti M, Bucci MG. Clinical ability of pattern-electroretinograms and visual evoked potentials in detecting visual dysfunction in ocular hypertension and glaucoma. Ophthalmology. 2006 Feb;113(2):216-28.
ASSESSMENT OF NEURO-VISUAL FUNCTION
OHT
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERG CLINICMaculopathies
ASSESSMENT OF NEURO-VISUAL FUNCTION
pERG CLINICGlaucoma Detection
ASSESSMENT OF NEURO-VISUAL FUNCTION
pERG CLINICGanglion Cell Function Recovery
ASSESSMENT OF NEURO-VISUAL FUNCTION
pERG CLINICMacular Function Recovery
ASSESSMENT OF NEURO-VISUAL FUNCTION
PERGPERG provides information about the functionality of the ganglion cells in the retina.
PERG provides information about reversibility of the ganglion cells functionality.
PERG provides the earliest information about ganglion cells dysfunctional.
Thanks
Q & A
ASSESSMENT OF NEURO-VISUAL FUNCTION