Dankumar
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The document discusses the development of an artificial retina using thin film transistor technology. It describes how retinal conditions like retinitis pigmentosa and age-related macular degeneration cause vision loss and how an artificial retina could help. The artificial retina would be implanted either on top of the retina (epiretinal) or underneath (subretinal) and use thin film transistors to detect light and stimulate remaining retinal cells via electrical pulses. Both approaches have advantages and disadvantages relating to attachment, heat dissipation, power requirements and image processing. Complications from long-term implantation are also addressed. The technology shows promise for restoring basic vision but has limitations and further development is still needed.
Dankumar
- 1. TECHNICAL SEMINAR ON “ARTIFICIAL RETINA USING THIN FILM TRANSISTOR TECHNOLOGY” ELECTRONICS & COMMUNICATION 1 DEPARTMENT OF ELECTRONICS AND COMMUNICATION By Yadav Dankumar v. Guided By Prof. Niraj Tevar
- 2. Introduction ELECTRONICS & COMMUNICATION,SCE(2014-15) 2 Fig 1:- Retina structure •Retina Structure •Retinitis Pigmentosa •Age-Related Macular Degeneration How it works.com
- 3. Thin-Film Transistor • Implanting classified into two types: Epiretinal implant and Subretinal implant . • Thin-Film Transistors, fabricated on transparent and flexible substrates. ELECTRONICS & COMMUNICATION,SCE(2014-15) 3 Fig 2 Fig 3 Fig 4 How it works.com
- 4. 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 ELECTRONICS & COMMUNICATION,SCE(2014-15) 4
- 5. Epiretinal Implant ELECTRONICS & COMMUNICATION,SCE(2014-15) 5 Fig 5 How it works.com
- 6. 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 humor External control over image processing allowing for customizability, possible better clarity • Disadvantages:- Difficulty attaching the implant to the fragile inner retina Complicated processing. ELECTRONICS & COMMUNICATION,SCE(2014-15) 6
- 7. Subretinal Implant ELECTRONICS & COMMUNICATION,SCE(2014-15) 7 Fig 6 How it works.com
- 8. 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 space Heat damage due to proximity of device to retinal cells Ambient light may not be adequate to generate current in this array ELECTRONICS & COMMUNICATION,SCE(2014-15) 8
- 9. 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 ELECTRONICS & COMMUNICATION,SCE(2014-15) 9
- 10. 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 ELECTRONICS & COMMUNICATION,SCE(2014-15) 10
- 11. • 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. ELECTRONICS & COMMUNICATION,SCE(2014-15) 11 Application:- Advantages:-
- 12. Conclusion ELECTRONICS & COMMUNICATION,SCE(2014-15) 12 •A pulse signal generator appropriate as photo recepter cells for implementation. •Shows the feasibility to implant the artificial retina into human eyeballs. Fig 7 How it works.com
- 13. Future scope ELECTRONICS & COMMUNICATION,SCE(2014-15) 13 Fig 8 How it works.com
- 14. Reference 1. 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 . ELECTRONICS & COMMUNICATION,SCE(2014-15) 14
- 15. ELECTRONICS & COMMUNICATION,SCE(2014-15) 15 ARTIFICIAL RETINA USING THIN FILM TRANSISTOR TECHNOLOGY