[Nfbf-l] Haptic lens converts light into touch.

[Alan Dicey]

Dear Friends,
I found this in my "In Box", I thought some might be interested in it.
I think it is simply incredible how many different "Technical Solutions" to 
finding a way to assist Blind people, that they are working on with so many 
different companies world wide.
With Best Regards,
God Bless,
Alan
Plantation, Florida

Haptic lens converts light into touch.
March 10, 2014 // Julien Happich.

A lot of research goes into bringing back some level of sight to visually 
impaired people. Often, researchers look into ways to connect artificial 
photoreceptors to retinal or optical nerves, bypassing the faulty retina 
through surgically implanted devices and microelectrodes.

But in the vast majority of people suffering from untreatable blindness, the 
cornea remains unaffected by disease-related retinal dis-functions, observes 
Prof. Zeev Zalevsky, a proponent of less intrusive solutions.

And according to anatomical studies, cornea is one of the most sensitive 
tissues of the body, densely innervated (distinctly from optic nerves which 
only transmit vision signals), with a density 300 to 600 times that of skin.

The nerves in question are sensory, producing touch, thermal and chemical 
sensations that drive the blink reflex necessary to preserve the integrity 
of the ocular surface, notes Zalevsky in a 2013 paper discussing the use of 
tactile corneal stimulation through Braille-like pressure points.

In recent research, Zalevsky has also demonstrated through human trials that 
the cornea's sensing capacity to discriminate between two points is around 
1mm,which in theory could allow the cornea to identify simple spatial shapes 
and images using adequate stimulation.

The Head of the Electro-Optics study program at Bar-Ilan Universitys' 
Faculty of Engineering (Israel) and director of the Nano Photonics Center at 
the Institute of Nanotechnology and Advanced Materials (BINA), Zalevsky 
together with Prof. Michael Belkin from Tel-Aviv University are now 
launching a startup called I C Touch with the goal to design a wearable 
haptic lens together with a dedicated image processing chip that would parse 
the input from a video camera into a time-multiplexed matrix of surface 
electrodes or micro-actuators embedded into the lens.

Although the initial clinical trials were done using hardwired tubing and 
air
pressure (using micro-channels to stimulate the cornea across discrete
points for the patient to recognize basic shapes), the ultimate goal would 
be to power and control such a lens wirelessly, using an embedded antenna 
coil and RF energy harvesting to drive surface electrodes.

"We started with pressure stimulation in order to prove our basic claim: 
that cornea has two points discrimination capability and can sense spatial 
shapes.
This is novel to the world of medicine and was never examined before" 
clarified Zalevsky in an email exchange with EE Times Europe.

"Another reason was that for pressure stimulation it is much simpler to get 
clinical approval for experiments. The third reason is that as in any R&D 
process there always many non-anticipated difficulties. So our aim is to do 
electrical stimulation which is simpler from the system point of view but it 
might not perform as well as expected so we have our fold back path of doing 
the pressure based stimulation which can also be realized in practice".

Currently Zalevsky's research team is experimenting with prototypes 
assembled manually from printed electronic circuits inserted between two 
soft lenses.
The current design includes pixels with a pitch of around 1mm, and the 
distance between the electrode and the cornea surface is around 50 microns.

Although the initial proof of concept was done using pressure stimulation, 
the team has to figure out what would be the right comfort zone for 
electrical stimulations to properly define the voltage level at which the 
stimulation would be felt without being disturbing to the user.

So what sort of practical information does the wearer get from such a haptic 
lens since we humans are not accustomed to make any sense of tactile 
feedback on the cornea?

Zalevsky describes a feeling similar to what someone would get when touching 
Braille writing with his/her fingertips.

"It is a feeling one can train to recognize similarly to how a blind person 
learns how to recognize the Braille alphabet through touch", explains 
Zalevsky.
And indeed, during preliminary trials, the researcher confirms that various 
transmitted shapes (lines, crosses, squares etc.) were recognized by the 
subjects about 9 times out of ten after only 2 minutes of training.

It only took a few minutes for the subjects to learn and distinguish between 
10 to 20 different shapes, but that could vary with the pixel density.

The current prototypes include electrodes which are like small antennas. The 
transmitted image induces voltages in them and the voltages do electrical 
stimulation of the cornea. Alternatively, electro-active polymers could be 
used to implement micro-actuators.

But once the concept proven, what sort of resolution would you get and would 
that be enough for basic obstacle avoidance?

"We aim to get a physical resolution of 100 pixels at the contact lens 
level. This after proper encoding in the camera will be equivalent to 1000 
pixels resolution at the object plane" explains Zalevsky.

"Therefore in order to improve the spatial resolution we intend to use time 
multiplexing, aiming to improve the resolution by almost another order of 
magnitude in each axis to produce a final image resolution of around 10,000 
pixels, as close to one million".

I C Touch thinks its findings could benefit visually impaired people but 
could also lead to new augmented reality applications, converting particular 
situational information into tactile feedback. In the future, the company 
aims to license the concept to third party manufacturers.


Source URL:
http://www.electronics-eetimes.com/en/haptic-lens-converts-light-into-touch.html?cmp_id=7&news_id=222920347

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