human visual system and retinal blindness notes - visual neural prosthetics.pdfhuman visual system...
TRANSCRIPT
![Page 1: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/1.jpg)
Human Visual System and Retinal Blindness•
• Retina is a light sensitive neural network
• Diseases such as Retinitis Pigmentosa (RP) and Age-related Macular Degeneration (AMD) primarily affect the photoreceptors, are both presently incurable, and render 100,000s blind each year
Webvision, Kolb, Fernandez, and Nelson, 2003.
![Page 2: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/2.jpg)
Retinal Prosthesis - Epiretinal vs. Subretinal
EpiretinalLess disruptive to the retina.More flexibility in component placementMore complex stimulus algorithms required
SubretinalIn natural position of photoreceptorsDisruptive to retinaDevices relying on incident light for power cannot generate effective stimulus
![Page 3: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/3.jpg)
State of the Art – Retinal Prostheses• Epiretinal and Subretinal at Investigational
Device Exemption Stage• Epiretinal - encouraging results, but better
technology required• Subretinal – No direct evidence demonstrating
functional electrical stimulation, but patients report subjective improvements in vision
Optobionics ASRTM Second Sight, Model ITM
![Page 4: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/4.jpg)
Overview
Basics of Electrical Stimulation of NerveLimits on stimulating electrodes
Development of a Model 1 retinal prosthesisDisease targetsEarly clinical trialsPreclinical research to specify designClinical trial with implantable system
Future work
![Page 5: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/5.jpg)
Electrical Stimulation of Nerve
![Page 6: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/6.jpg)
Electrode-Retina Interface Design ParametersElectrode diameter.Electrode position.Stimulus waveform
Ganglion Cell LayerBipolar Cell Layer
Photoreceptor Layer
![Page 7: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/7.jpg)
Stength Duration Curve
S1 - M2
0
100
200
300
400
500
600
0 2 4 6 8 10
ms
mic
roA
mps
![Page 8: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/8.jpg)
Dose –Response Curve
M5, 6-27-02
0
2
4
6
8
10
12
0 100 200 300 400 500 600
pulse amplitude (uA)
Perc
eive
d Br
ight
ness
![Page 9: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/9.jpg)
Is a retinal prosthesis feasible?
Electrical stimulation of globe in humans with RP can elicit flashes of light but….are any retinal cells left to stimulate? Or
does stimulation of the globe actually stimulate optic nerve?can focal perceptions be created? Or will
people see only flashes that make no sense?
![Page 10: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/10.jpg)
Mean Cell Count from Post-Mortem RP Eyes
Intraocular Retinal Prosthesis Group © 2000
Group Age,y OuterNuclearLayer
InnerNuclearLayer
GanglionCell Layer
Moderate 73.56±11.19 12.91±17.59* 37.61±10.45 9.21±4.2*
Severe 76.17±8.89 2.33±2.95* 33.37±9.71* 5.72±4.13*
Normal 75.58±10.12 46.9±12.73 42.56±11.56 19.16±5.91
P (UsingF test ofVariance)
0.83 <0.01 0.08 <0.001
![Page 11: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/11.jpg)
Ganglion Cell Layer
05
1015202530354045
-1500-1300-1100
-900-700-500-300-100 100 300 500 700 900110013001500
Eccentricity (µm)
Num
ber o
f Cel
ls
ControlGA
![Page 12: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/12.jpg)
Inner Nuclear Layer
0
20
40
60
80
100
120
140
-1500-1300-1100
-900-700-500-300-100 100 300 500 700 900110013001500
Eccentricity (µm)
Num
ber o
f Cel
ls
ControlGA
![Page 13: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/13.jpg)
Outer Nuclear Layer
0
10
20
30
40
50
60
70
-1500-1300-1100
-900-700-500-300-100 100 300 500 700 900110013001500
Eccentricity (µm)
Num
ber o
f Cel
ls
ControlGA
![Page 14: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/14.jpg)
Condition of retina in RP
Cell counts indicate inner retina survivalMore recent studies of RP shows significant
alteration of retinal circuitry (Marc, 2003)Glial sheath between inner retina and subretinalspaceAnomalous rewiring and cell migration complicates transformation between image and stimulation pattern
![Page 15: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/15.jpg)
Intraocular Retinal Prosthesis Group © 2000
![Page 16: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/16.jpg)
Summary Data from Acute Trials
Intraocular Retinal Prosthesis Group © 2000
Charge (µC)ColorPerceptVisionConditionSubject
0.2WhiteFireflyLPRPJL
1.4WhiteBoxLPRPJT
1.2WhitePinLPRPHW
1.0YellowPinLPRPVO
2.4BluePinLPRPCS
0.3WhitePin20/400AMDAB
1.1WhitePinNLPRPBH
1.8YellowPinLPRPRJ
1.6YellowPinLPRPBC
2.8YellowPeaLPRPPS
6.0WhitePencilNLPAMDWG
3.2YellowPinLPRPRS
0.16YellowMatchheadNLPRPCC
0.95??LPRet-DegenAD
0.4Yellow-GreenLetterNLPRPHC
![Page 17: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/17.jpg)
Electrical Stim in Normal Eyes
In eyes scheduled for removal (cancerous), artificial, focal photoreceptor loss created.Electrical stimulation in retina with
photoreceptors resulted in large, dark perceptionElectrical stimulation in retina without photoreceptors resulted in small, light percepts
![Page 18: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/18.jpg)
Conclusions from Early Human Studies
Degeneration not uniform across retina, most severe in the photoreceptorsElectrical stimulation of retina in blind humans suggest retinal prosthesis possible:
Focal perceptsSpatial correlation between electrode position and percept location
Threshold stimulus current high: 600 uA for 1 ms on average.
![Page 19: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/19.jpg)
Preclinical studies
Chronic implant studies to assess safety of implantation and stimulation, surgical attachment methodsIsolated retina studies to study stimulus thresholds
![Page 20: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/20.jpg)
![Page 21: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/21.jpg)
Chronic Stimulation
180 uA and 90 uA pulses applied, 8-10 hours/day, 60 pps.Histology shown from retina under electrode array after 60 days of stimulation over 4 months of implantation.Morphometric analysis underway on 3 normal and 3 RCD1 dogs that underwent 60-120 days of stimulation
![Page 22: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/22.jpg)
Cortical Recording Methods
After completion of stimulation protocol, subdural electrode implanted.Synchronization of electrical stimulus with data acquisition system.100 averages, multi-channel stimulus.
![Page 23: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/23.jpg)
EER elicited by retinal stimulator
-60
-40
-20
0
20
40
60
0 100 200 300 400 500 600
msec
mic
roV
olts A
BCD
![Page 24: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/24.jpg)
Electrical stimulation of isolated retina
Measure threshold stimulus for retina ganglion cell responseCompare normal vs. diseased retinaJ.S. Shyu, M. Maia, T. O’Hearn
![Page 25: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/25.jpg)
RecordingElectrodePair
1.5-2 mm
Optic Disc
StimulatingElectrodePair
RGC Axons
Isolated Retina: Electrode Position
![Page 26: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/26.jpg)
Stimulating Multi-microelectrode Plate( MMEP)
retina
Recording electrodes
Stimulating Macroelectrodes
![Page 27: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/27.jpg)
Isolated Retina: RGC responses
Electrical Stimulation and Induced Responserd Retina
-3
-2
-1
0
1
2
3
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0
Time (msec)
µVo
lts
cathodic(1mS)
interphase delay (3mS)
anodic(1mS)
measured response latency
![Page 28: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/28.jpg)
Isolated Retina: Stimulus Thresholds
2.69 +/- 0.31 ms
2.11 +/- 0.43 ms
Stimulus Latency(P=0.0278)
111.2 uC/cm261.2 uC/cm2Charge Density
54.57+/-12.45 uA
30.04 +/-11.43 uA
Stimulus threshold(P=0.0597)
rdNormal
![Page 29: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/29.jpg)
Results – Isolated Frog Retina
Stimulus Duration (msec)
0.01 0.10 1.00 10.00 100.00
Cur
rent
Thr
esho
ld (u
A)
10
100
1000
10000
Cadmium
Dark
Light
![Page 30: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/30.jpg)
Summary from other studies
Humayun 200310-1000 nCPerceptionEpiretinal Blind Human, Chronic
Zrenner 200450 nCCortical responseSubretinal Stimulation, Normal Cat
Hesse 200014 nCCortical responseEpiretinal Stimulation, Normal Cat
Stett 19999 nCRGC responsesSubretina, isolated chick retina
Grumet 20002 nCRGC responsesEpiretinal, Isolated Normal Rabbit retina
Rizzo 2003300-500 nCPerceptionEpiretinal, Blind Human Acute
Humayun 1996600 nCPerceptionEpiretinal, Blind Human Acute
Lead AuthorThresholdDetection MethodModel
![Page 31: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/31.jpg)
Conclusions from preclinical studies
Device can be safely implanted on the retinaElectrical stimulation up to 0.1 mC/cm2 does
not damage retinaStimulus thresholds in animal models 1 order of magnitude less than in humans
![Page 32: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/32.jpg)
Prototype Human Retinal Prosthesis
![Page 33: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/33.jpg)
Retinal Implant Surgery
![Page 34: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/34.jpg)
![Page 35: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/35.jpg)
![Page 36: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/36.jpg)
OCTCan provide quantitative information about retina-implant interface.
![Page 37: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/37.jpg)
ElectrophysiologySF VERs were non-recordable at every session. Sub-threshold EERs were non recordable when using lowest levels.
![Page 38: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/38.jpg)
Electrophysiology
07/12/02
L7
L8
L5
L6
L4
L3
L2
M5
M7L1 M3
M6 M2
M1
M4M8 All at 10 cu-50 cu
-10 cu
baseline
![Page 39: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/39.jpg)
Longitudinal Series – Baseline EER
N1-P14.49
N1-P16.05
N1-P18.78
7 electrod.base.-10cu691 µamp
(98.71)
8 electrod.1791 mamp
(223.87)
8 electrod.1111 µamp
(138.87)
Electrophysiology
03/12/02
06/19/02
07/09/02
![Page 40: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/40.jpg)
HEC01 Spatial Map - Horizontal
M1M5
M6
M7
L5
L7
L1
L3
L2
L6
L4
L8
M2
M3
L6 L2
L1
L4
L3
M2
M4
M6
M8
M5 M1
M7 M3
L7
L5
L8
Patient Reported LocationsExpected Results based on Retinal Location
![Page 41: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/41.jpg)
HEC01 Spatial Map - Vertical
M1M5
M6
M7
L5
L7
L1
L3
L2
L6
L4
L8
M2
M3L6 L2
L1
L4
L3
M2
M4
M6
M8
M5 M1
M7 M3
L7
L5
L8
Patient Reported LocationsExpected Results based on Retinal Location
![Page 42: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/42.jpg)
Strength Duration CurvesS1 - M2
0
100
200
300
400
500
600
0 2 4 6 8 10
ms
mic
roA
mps
S1 - M5
020406080
100120140160
0 2 4 6 8 10
ms
mic
roA
mps
L2
0200400600800
1000
0 2 4 6 8 10ms
mic
ro A
mps
• Chronaxie 1-2 ms
![Page 43: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/43.jpg)
Stimulus Thresholds
10 - 91CS
43 - 679YSL
28-949HEC
Threshold range, Day 1(in uA, 1 ms, biphasic pulse)
Subject
![Page 44: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/44.jpg)
Response Thresholds
![Page 45: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/45.jpg)
Computer Controlled TestingTest type HEC01 YSL02 CS03
Sequential activation
4AFC (25%) 16/24 (67%) 28/30 (93%) 20/40 (50%)
Form vision (Row vs. column)
2AFC (50%) 19/32 (59%) 29/30 (97%) 23/30 (77%)
Spatial Location 2AFC (50%) 79/109 (72%)
60/60 (100%) 40/60 (67%)
![Page 46: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/46.jpg)
Object location
![Page 47: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/47.jpg)
Object Recognition
![Page 48: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/48.jpg)
Rows and Columns
![Page 49: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/49.jpg)
Camera Tests
Camera still Test type HEC01 YSL02 CS03
Lights on/off 2AFC (50%) 10/10 (100%)
20/20 (100%)
9/10 (90%)
Moving directions
4AFC (25%) 4/8 (50%) 26/30 (87%) 12/30 (40%)
![Page 50: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/50.jpg)
Camera Tests
19/30 (63%)22/30 (73%)5/10 (50%)4AFC (25%)L position
19/30 (63%)22/30 (80%)40/60 (67%)3AFC (33%)Objects recognition (plate, knife and cup)
31/40 (78%)34/40 (85%)23/30 (77%)4AFC (25%)Counting/finding objects (Ø, R, L, R+L)
23/30 (77%)30/30 (100%)9/10 (90%)3AFC (33%)Finding objects (Ø, R, L)
CS03YSL02HEC01Test TypeScanning
![Page 51: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/51.jpg)
Multi-Pixel vs. Single Pixel
Camera set to either map a single pixel to all electrodes or to map individual pixels to individual electrodes12 cases (4 visual tasks x 3 subjects)
2 showed statistically higher accuracy with multi-pixel setting10 were not statistically different (5 better accuracy, 3 same, 2 worse)
![Page 52: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/52.jpg)
Figure 8. Panel A. Height above the retina versus impedence. Panel B. Height above the retina versus threshold (on log axes). The shaded gray shows the amount of the height above the retina that can be attributed to the thickness of the electrode
S2aS2bS3
Height above retina (mm)
Impe
denc
e (kΩ
)
Height above retina (mm)0.2 0.5 1 1.5 20
10
20
30
40
50
60
0.2 0.5 1 1.5 25
1020
50
100200
5001000
Thre
shol
d (µ
Am
ps)
A. B.
![Page 53: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/53.jpg)
Simulations of prosthetic vision
Cha, Horch, and Normann simulated pixelizedfoveal vision.
25x25 – easy mobility, 100 words/minute reading
Simulation of retinal implant16x16 macular pixels – 15 words/minute reading (Hayes, et al)10x10 face recognition above chance (Dagnelie, et al)32x32 80% face recognition (Dagnelie, et al)
![Page 54: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/54.jpg)
Simulation of Prosthetic Vision
![Page 55: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/55.jpg)
Retinal Prosthesis – Systems Level Description
External camera/image processor detects image and performs conversion to digital informationTelemetry link between external and implanted unitsImplanted unit recovers power and dataImplanted unit applies commanded stimulus patternto the retina via amicroelectrode array onthe surface of the retina
![Page 56: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/56.jpg)
![Page 57: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/57.jpg)
DOE Implants – PDMS electrode
Goal: To develop a PDMS substrate stimulating electrode Progress:
Four normal sighted dogs were implanted. Three of them have been followed for 3 months, 2 months and 1 month. Multilayer cable PDMS test devices were received and evaluated.
![Page 58: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/58.jpg)
Implantation of LLNL device #4
Postoperative 1st month OCT imaging (horizontal scan)
Postoperative 1st month OCT imaging (vertical scan)
DOE Implants – PDMS Electrode
![Page 59: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/59.jpg)
#2 LLNL dog, postoperative 2nd month, OCT imaging
#2 LLNL dog, postoperative 3rd month, OCT imaging
#3 LLNL dog, postoperative 1st month, OCT imaging
#3 LLNL dog, postoperative 2nd month, OCT imaging
DOE Implants – PDMS Electrode
![Page 60: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/60.jpg)
DOE Implants – Spring arrayGoal: To develop silicon based electrode array with MEMS springs for z-axis alignment
Progress: Received two samples of PDMS frame without spring loaded electrodes
Plan: When spring devices received, perform acute and chronic experiments to assess mechanical interface and surgical biocompatibility
![Page 61: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/61.jpg)
Retinal Implant – MEMS Component
microelectronics
electroplated or assembled electrodes
bulk micromachinedelectrode seats
surface micromachinedsprings(polymer) frame
flexible frame for attachment
micromachined electrode array (silicon substrate)
retina
posts for assembly and electrical interconnect
electrodes
flexibleinterconnecttack
antenna
inner-eyeelectronics
![Page 62: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/62.jpg)
![Page 63: Human Visual System and Retinal Blindness Notes - Visual Neural Prosthetics.pdfHuman Visual System and Retinal Blindness • • Retina is a light sensitive neural network • Diseases](https://reader031.vdocuments.us/reader031/viewer/2022041715/5e4ad769f6f9602a4f28ea9e/html5/thumbnails/63.jpg)
Conclusions
Current clinical trial has produced promising results
Low thresholds on some electrodesCorrelation with height from retinaSubjects can sense motion, recognize objects
Active research projects working towards higher density devices