Researchers at Lawrence Livermore are today using advanced polymer-based micro-fabrication methods to further develop a biocompatible microelectrode array for the third-generation artificial retina device.

The LLNL team contributes three major components to the artificial retina: the thin-film electrode array that contains the neural electrodes; the biocompatible electronics package that contains the electronics for stimulating the retina and wireless power and communications; and an ocular surgical tool that will enable the insertion, attachment, and re-insertion of the thin-film electrode array.

The second-generation device represents a substantial performance improvement over the first-generation device in speed of recognition and resolution. Objects can now be recognized within 2-3 seconds instead of the previous 15, and the device’s 60 electrodes have improved image resolution over the 16-electrode prosthesis.

The prosthesis is now of sufficient resolution to allow recognition of doors, windows, edges, low-lying branches and a basketball backboard. The goal of the DOE project is to produce a prosthesis with more than 1,000 electrodes, which would allow facial recognition.

Expertise in biomedical microsystems at Lawrence Livermore’s Center for Nano- and Microtechnology was tapped to develop a “flexible microelectrode array,” able to conform to the curved shape of the retina, without damaging the delicate retinal tissue, and to integrate electronics developed by University of California at Santa Cruz. The device serves as the interface between an electronic imaging system and the human eye, directly stimulating neurons via thin film conducting traces and electroplated electrodes.

Link: Lab plays key role in Department of Energy's artificial retina project...

Flashbacks: Second Sight Medical Retinal Prosthesis Receives FDA Approval for Clinical Trials; Second Sight Medical Retinal Prosthesis to Receive a Wider Trial

LLNL video of wafer manufacturing after the fold (direct link to Quicktime video file):

Some surgeons who operate under the microscope are even starting to use TrueVision as their primary visualization device instead of the microscope. Also, the TrueVision system can integrate into current guidance technologies to bring all of the surgical visual data together onto one screen.

From the press release on guidance integration:

For the first time ever, surgeons can connect other operating room devices into one unified visualization system. TrueVision seamlessly integrates into the multi-window 3D 1080p display the various imaging modalities and guidance from other medical devices such as Alcon INFINITI, Medtronic Stealth Station, and Intuitive Surgical’s DaVinci robot. This allows the surgeon and staff to focus on one screen in the OR to view data and the surgical field of view at the same time as opposed to looking at different displays for each device.

Here's a TrueVision video of the system used during surgery:

Product Page: True Vision

Press Release: True Vision Guidance Platform...

From UC Davis Health System:

Using cadavers, the surgeons inserted a sling made of muscle fascia or implantable fabric around the eye. Small titanium screws secured the eyelid sling to the small bones of the eye. The sling was attached to a battery-operated artificial muscle. The artificial muscle device and battery were into a natural hollow or fossa at the temple to disguise its presence.

Senders and Tollefson found that the force and stroke required to close the eyelid with the sling were well within the attainable range of the artificial muscle. This capability may allow the creation of a realistic and functional eyelid blink that is symmetric and synchronous with the normal, functioning blink. A similar system also could give children born with facial paralysis a smile.

The three-layered artificial muscle was developed by engineers at SRI International of Palo Alto, Calif., in the 1990s. Inside is a piece of soft acrylic or silicon layered with carbon grease. When a current is applied, electrostatic attractions causes the outer layers to pull together and squash the soft center. This motion expands the artificial muscle. The muscle contracts when the charge is removed and flattens the shape of the sling, blinking the eye. When the charge is reactivated, the muscle relaxes and the soft center reverts back to its original shape.

An implanted battery source similar to those used in cochlear implants would power the artificial muscle.

For patients who have one functioning eyelid, a sensor wire threaded over the normal eyelid could detect the natural blink impulse and fire the artificial muscle at the same time. Among patients lacking control of either eyelid, an electronic pacemaker similar to those used to regulate heartbeats could blink the eye at a steady rate, and be deactivated by a magnetic switch.

The researchers are now refining the technique on cadavers and animal modes. They estimate the technology will be available for patients within the next five years.

Abstract in Archives of Facial Plastic Surgery: Force Requirements for Artificial Muscle to Create an Eyelid Blink With Eyelid Sling

Press statement from UC Davis Health System: Artificial muscles restore ability to blink, save eyesight...

Published features from the product page:

Automated, easy to use test - specifically designed for elderly people.

Home use - familiar environment reduces anxiety and increases test frequency.

Personalized test customized to specific user - higher sensitivity.

Automatic analysis - immediate alert (if needed).

Controlled environment - accurate results.

Data export - off line, in-dept analysis capabilities.

More from Globes [online]: Notal Vision gets FDA nod for AMD home diagnostic kit...

Product page: ForeseeHome...

Product design info...

Technology Review reports on work by the Institute for Bioengineering and Nanotechnology (IBN) in Singapore to use the entire volume of the lens to contain the dye:

Conventional transition sunglasses are coated with millions of molecules of photochromic dyes, which are transparent when out of the sun. These molecules change shape when UV light hits, enabling them to absorb UV light and triggering the darkening of the lens. When UV light disappears, the molecules change back to their original shape and transparent appearance.

Few previous attempts have been made to design transition contact lenses, largely because it's difficult to apply dye coatings uniformly to the delicate, soft surface of a contact lens. Ying and her colleagues got around this by developing a contact lens that embeds dyes uniformly throughout the material. This approach allowed them to pack more dye molecules into the material, Ying says, giving the contact lens greater sensitivity to light and thus a faster response.

Researchers created the spongy nanostructure material by mixing specific combinations of water, an oil solution with monomers commonly used in contact lenses, and a novel surfactant-- a compound that encourages mixing between water and oil solutions. The resulting material is studded with tiny pores and tunnels, which can be loaded with agents such as UV-sensitive dyes.

Read on at Technology Review...

CYCLOPS's camera is gimballed, which means it can emulate left-to-right and up-and-down head movements. The input from the camera runs through the onboard computing platform, which does real-time image processing. For now, however, the platform itself is moved around remotely, via a joystick. “The platform can be operated from anywhere in the world, through its wireless Internet connection,” says Tarbell [Mark Tarbell, Caltech visiting scientist --ed.].

"We have the image-processing algorithms running locally on the robot's platform—but we have to get it to the point where it has complete control of its own responses," Fink [Wolfgang Fink, visiting associate in physics at Caltech] says.

Once that's done, he adds, "we can run many, many tests without bothering the blind prosthesis carriers."

Among the things they hope to learn from such testing is how to enhance a workplace or living environment to make it more accessible to a blind person with a particular vision implant. If CYCLOPS can use computer-enhanced images from a 50-pixel array to make its way safely through a room with a chair in one corner, a sofa along the wall, and a coffee table in the middle, then there is a good chance that a blind person with a 50-pixel retinal prosthesis would be able to do the same.

The results of tests on the CYCLOPS robot should also help researchers determine whether a particular version of a prosthesis, say, or its onboard image-processing software, are even worth testing in blind persons. "We'll be coming in with a much more educated initial starting point, after which we'll be able to see how blind people work with these implants," Fink notes.

Full story from Caltech: Caltech Scientists Create Robot Surrogate for Blind Persons in Testing Visual Prostheses...

Abstract in Computer Methods and Programs in Biomedicine: CYCLOPS: A mobile robotic platform for testing and validating image processing and autonomous navigation algorithms in support of artificial vision prostheses

The implant works in conjunction with a specially designed set of glasses that have an embedded camera that wirelessly transmits power and image signals to the microchip in the retina which then transmits the signals to the brain. The microchip has receiving coils that surround the eyeball, much like a natural retina. The microchip itself is sealed in a titanium case to avoid corrosion. The chip will receive visual signals from the glasses which activate the electrodes, which in turn fire nerve cells to carry visual input to the brain. The microchip will not restore vision to a perfect standing, but is intended to help a blind patients navigate.

The following is taken from an MIT press office statement:

One question that remains is what kind of vision this direct electrical stimulation actually produces. About 10 years ago, the research team started to answer that by attaching electrodes to the retinas of six blind patients for several hours.

When the electrodes were activated, patients reported seeing a small number of "clouds" or "drops of blood" in their field of vision, and the number of clouds or blood drops they reported corresponded to the number of electrodes that were stimulated. When there was no stimulus, patients accurately reported seeing nothing. Those tests confirmed that retinal stimulation can produce some kind of organized vision in blind patients, though further testing is needed to determine how useful that vision can be.

After those initial tests, with grants from the Boston Veteran's Administration Medical Center and the National Institutes of Health, the researchers started to build an implantable chip, which would allow them to do more long-term tests. Their goal is to produce a chip that can be implanted for at least 10 years.

One of the biggest challenges the researchers face is designing a surgical procedure and implant that won't damage the eye. In their initial prototypes, the electrodes were attached directly atop the retina from inside the eye, which carries more risk of damaging the delicate retina. In the latest version, described in the October issue of IEEE Transactions on Biomedical Engineering, the implant is attached to the outside of the eye, and the electrodes are implanted behind the retina...

While they have not yet begun any long-term tests on humans, the researchers have tested the device in Yucatan miniature pigs, which have roughly the same size eyeballs as humans. Those tests are only meant to determine whether the implants remain functional and safe and are not designed to observe whether the pigs respond to stimuli to their optic nerves.

So far, the prototypes have been successfully implanted in pigs for up to 10 months, but further safety refinements need to be made before clinical trials in humans can begin.

Press release: Stimulating sight...

MIT Research Lab: Retinal Implant Research Group...

Flashback : Experimental Bionic Eyes Give Hope to Totally Blind

Link @ TED: Josh Silver demos adjustable liquid-filled eyeglasses

Flashback: TruFocals Offer New Option For Presbyopic Eyes

From the article:

The glucose detectors we’re evaluating now are a mere glimmer of what will be possible in the next 5 to 10 years. Contact lenses are worn daily by more than a hundred million people, and they are one of the only disposable, mass-market products that remain in contact, through fluids, with the interior of the body for an extended period of time. When you get a blood test, your doctor is probably measuring many of the same biomarkers that are found in the live cells on the surface of your eye—and in concentrations that correlate closely with the levels in your bloodstream. An appropriately configured contact lens could monitor cholesterol, sodium, and potassium levels, to name a few potential targets. Coupled with a wireless data transmitter, the lens could relay information to medics or nurses instantly, without needles or laboratory chemistry, and with a much lower chance of mix-ups.

Three fundamental challenges stand in the way of building a multipurpose contact lens. First, the processes for making many of the lens’s parts and subsystems are incompatible with one another and with the fragile polymer of the lens. To get around this problem, my colleagues and I make all our devices from scratch. To fabricate the components for silicon circuits and LEDs, we use high temperatures and corrosive chemicals, which means we can’t manufacture them directly onto a lens. That leads to the second challenge, which is that all the key components of the lens need to be miniaturized and integrated onto about 1.5 square centimeters of a flexible, transparent polymer. We haven’t fully solved that problem yet, but we have so far developed our own specialized assembly process, which enables us to integrate several different kinds of components onto a lens. Last but not least, the whole contraption needs to be completely safe for the eye. Take an LED, for example. Most red LEDs are made of aluminum gallium arsenide, which is toxic. So before an LED can go into the eye, it must be enveloped in a biocompatible substance.

Link @ IEEE Spectrum: Augmented Reality in a Contact Lens...

Side image: One lens prototype [top] has several interconnects, single-crystal silicon components, and compound-semiconductor components embedded within. Another sample lens [bottom] contains a radio chip, an antenna, and a red LED

Flashback: Electronic Contact Lenses for Better Vision

Here's Stephen Kurtin presenting the TruFocals:

Product page: TruFocals...

Review of TruFocals by John Markoff at the New York Times...

Flashback: Water Power in Developing World to Cure Poor Eyesight