dankumar

TECHNICAL SEMINAR ON

“ARTIFICIAL RETINA USING THIN FILM TRANSISTOR TECHNOLOGY”

ELECTRONICS & COMMUNICATION1

DEPARTMENT OF ELECTRONICS AND COMMUNICATION

ByYadav Dankumar v. Guided By

Prof. Niraj Tevar

Introduction

ELECTRONICS & COMMUNICATION,SCE(2014-15) 2

Fig 1:- Retina structure

•Retina Structure

•Retinitis Pigmentosa

•Age-Related Macular Degeneration

How it works.com

Thin-Film Transistor

• Implanting classified into two types: Epiretinal implant and Subretinal implant .

• Thin-Film Transistors, fabricated on transparent and flexible substrates.


Fig 2 Fig 3 Fig 4 How it works.com

Retinal Prostheses

• Retinal prosthesis replaces function of the photoreceptors and

detects light

• Signal from prosthetic detected by inner retinal cells– generally

via electrical impulses

• Chemical signals that replicate neurotransmitter function are

also being proposed

• Safe, biocompatible, effective and able to withstand the watery,

salty eye environment


Epiretinal Implant


Fig 5 How it works.com

Epiretinal Implant• Advantages:-

Minimizes the amount of microelectronics implanted and upgrades are easy to do on the wearable portion thus avoiding future surgery

Heat can be dissipated into the vitreous humorExternal control over image processing allowing for

customizability, possible better clarity

• Disadvantages:-Difficulty attaching the implant to the fragile inner retinaComplicated processing.


Subretinal Implant



Subretinal Implant• Advantages

Utilizes the surviving bipolar cells – the next step in the pathway –Retinal processing can take place

Placing the micro photodiodes between layers on the retina will allow for it to be held in position next to functioning cells

Proximity with existing neurons requires less current and leads to better resolution

• Disadvantages:Limited spaceHeat damage due to proximity of device to retinal cellsAmbient light may not be adequate to generate current in this

array


Device Complications• Long term Complications

Replacement of vitreous fluid with saline may cause irritation or damage to retinal surface

Irritation or damage due to long term electrical stimulus, and residual heat

Ionic interactions between retinal cells and metallic electrodes may cause long term degradation to tissue


Limitations• Devices are not expected to produce full, clear vision. • Allows patient to perceive basic shapes, direction of

movements, boundaries between contrasting objects.

• Subretinal:-Not yet clear whether solar power is sufficient to create

threshold stimulus to retinal cells.• Epiretinal:-Head-mounted cameras do not respond to natural eye

movement


• Bio-Electronic implant reduces the requirement of donor eye.

• Partial recovery of eye sight is possible.

• Effects of Retinitis Pigmentosa can be reduced.

• ARMD can be stopped from advancing.


Application:-

Advantages:-

Conclusion


•A pulse signal generator appropriate as photo recepter cells for implementation.

•Shows the feasibility to implant the artificial retina into human eyeballs.


Future scope


Fig 8How it works.com

Reference1. Yuta Miura, Tomohisa Hachida, and Mutsumi Kimura,

Member, IEEE , “Artificial Retina Using Thin-Film Transistors Driven by Wireless Power Supply” IEEE SENSORS JOURNAL, VOL. 11, NO. 7, JULY 2011.

2. David C. Ng, Chris E. Williams, Penny J. Allen, Shun Bai, Clive S. Boyd, Hamish Meffin, Mark E. Halpern, and Efstratios Skafidas “wireless power delivery for retinal prosthesis” , 33rd Annual International Conference of the IEEE EMBS Boston, Massachusetts USA, August 30 - September 3, 2011 .



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ARTIFICIAL RETINA USING THIN FILM TRANSISTOR TECHNOLOGY

dankumar

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