05-07-2014, 10:27 AM
Artificial Silicon Retina
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Introduction
Disease causing photoreceptor degeneration
Retinitis Pigmentosa (RP)
Genetic Disease
Progressive
Available treatments
Antioxidants (Vitamin A palmitate)
Delay of disease progression(1)
Artificial Silicon Retina
Not a therapeutic
Will only act as a replacement for photoreceptors
ASR Manufacturing
3 in. n-type silicon wafer
Ion implantation to form P+ doped wells
Channel stops by photomasking
Back of wafer N+
Deposition of Cr
Deposition of Au
Wafer saw to cut 3mm squares
Machined to 2mm dia
Regulatory Aspects
Low vision devices
All low vision devices are Class I
Colored contact less is the only Class II device
ASR, Class III
Permanent implantation
No predicate device
Animal trials
Selection of suitable animal model
Cats have retinal and chroidal circulation like humans
Results
No infection or inflammation of retina
Loss of Au exposed Cr
Selection of Ti and Pt for future devices
Clinical Trials
Safety study
To analyze safety of the device
Inclusion criteria
Age, 40 years of more
No other diseases such as diabetes, glaucoma, uveitis and cardiac diseases.
Snellen visual acuity measurement of 20/800 OU or worse
Ability to perceive phosphenes
Clinical Trials
Six patients were inducted in the study
ASR was implanted in the right eye
Post-operative follow up after 6 and 18 months
No signs of rejection, corrosion or migration
Two patients had improved brightness perception
Conclusion
Initial study indicate ASR is biocompatible with the human eye
No general trend in the improvement of visual characteristic