Who invented retinal implants

RS Disclosures: Dr. Humayun is a consultant, equity owner and holds patents with Second Sight Medical Products, from whom he also receives lecture fees and grant support. Hahn is a consultant to Second Sight. Foerster O. J Psychol Neurol. Tassicker GE, inventor. Retinal stimulator. US patent The sensations produced by electrical stimulation of the visual cortex. J Physiol. Multiple factors may influence the performance of a visual prosthesis based on intracortical microstimulation: nonhuman primate behavioural experimentation.

J Neural Eng. Ectopic expression of a microbial-type rhodopsin restores visual responses in mice with photoreceptor degeneration. The Artificial Synapse Chip: a flexible retinal interface based on directed retinal cell growth and neurotransmitter stimulation. Artif Organs. Electrotactile vision substitution for 3D trajectory following. Retinal implants: a systematic review.

Br J Ophthalmol. Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS. Proc Biol Sci. Rizzo JF 3rd. Update on retinal prosthetic research: the Boston Retinal Implant Project. J Neuroophthalmol. Implantation and explantation of a wireless epiretinal retina implant device: observations during the EPIRET3 prospective clinical trial.

Invest Ophthalmol Vis Sci. Implantation and explantation of an active epiretinal visual prosthesis: 2-year follow-up data from the EPIRET3 prospective clinical trial. Eye Lond. Progress in the development of vision prostheses.

The Argus II epiretinal prosthesis system allows letter and word reading and long-term function in patients with profound vision loss. Am J Ophthalmol. Humayun is the Cornelius J. Pings Chair in Biomedical Sciences; professor of ophthalmology, biomedical engineering, and cell and neurobiology; director, Institute for Biomedical Therapeutics; and co-director, University of Southern California Eye Institute, Los Angeles. Hahn is assistant professor of ophthalmology for vitreoretinal surgery and diseases at Duke University Eye Center.

The journey of artificial restoration of vision began in when Otfrid Foerster reported that electrical stimulation of the occipital cortex caused a subject to see a phosphene a spot of light produced by direct stimulation of the visual system.

Table 1. Characteristics of current retinal implants. Argus II consists of an external wearable and internal surgically implanted component. The glasses hold a miniature video camera in the nasal bridge that transmits images to the wired VPU for image processing. A bionic eye sees like you see a pixelated image or staring at a digital scoreboard held just in front of your eyes.

There are regions of light and dark that collectively the brain recognises as an image. The vision it produces is not crystal-clear. But one can see shapes and lights and with additional physical therapy, one will be able to find his way around a room and move through a group of people.

Users can identify a triangle versus a circle and a square. For patients, though, the whole thing is remarkably simple. The surgery to implant the electrodes takes just a few hours and patients go home the same day with an implant that wraps around one of their eyes and is secured by a tiny tack the size of a human hair.

After about a week to heal, the patient returns to get the glasses, to have their new electrodes tuned, and to train them on how to use the system. On the converter box there are knobs that let users increase or decrease things like the brightness and contrast.

Then they go home with their new pair of eyes. Robert Greenberg, the president and CEO of Second Sight, the company that developed Argus II says Second Sight is working on a new implant that bypasses even the retinal layer, and implants electrodes directly onto the visual region of the brain.

An Indian scientist, along with his US colleagues, has developed a device to restore the sight of people who go blind due to conditions such as retinitis pigmentosa and age-related macular degeneration. It has been used by 37 patients in the US and Europe, who were completely blind for 30 years. The device bionic eye or retinal implant has been co-invented by Dr.

Rajat N Agrawal, an assistant professor of clinical ophthalmology at the University of Southern California. He holds the patent for the device along with his colleagues. Agrawal wants to bring the device to India by producing a cheaper version with the help of Indian scientists.

He has founded a non-governmental group called Retina India to carry out the research. The main sign of the disease is the presence of dark deposits in the retina. The disease impacts central vision, which permits a person to read, drive, and perform activities that require sharp, straight-ahead vision. Now you can reach our senior doctors by booking an online video consultation or a hospital appointment.

Ophthalmoplegia due to 3rd nerve palsy is a common occurrence, and is usually a sign of diabetes mellitus or a serious What is Hypertensive Retinopathy?

Hypertensive Retinopathy is damage to the retina an area at the back of the eye where So the software and external upgrades will go a long way. Beyond that, obviously these devices are made to be removable. We have removed them from some patients, and in the preclinical studies, we had to show that we could remove them. But first, you have to set the expectations—this is not consumer electronics.

Mike Jumper: I understand the surgical technique for implanting the Argus II involves a pars plana approach similar to scleral buckling with vitrectomy. Could you elaborate?

Mark Humayun: Most of the steps and procedures of Argus II implantation are familiar to vitreoretinal surgeons. However, some parts are new, and the combination of surgical steps is unique and somewhat complex. There is a small electronics package and antenna that are all put around the eye underneath the muscles much like a scleral buckle is, so vitreoretinal surgeons feel very comfortable with that part of the procedure. However, their location on the eye needs to be very precise, and you have to be much more careful not to damage the antenna and the electronics.

After that is a pars plana vitrectomy. The next part is something new: we have to enlarge the sclerotomy, put the electrode array in, and then close the sclerotomy around the cable. Although the incision in the sclera is large to get the electrode array in—closer to 5 mm—you can close it all down to sub-2 mm. The next step is to tack the electrode array, centered on the macula, to the retina.

So the last 2 steps of putting in an electrode array through the sclera and then being able to tack it involve new techniques that retina surgeons can readily and easily learn. And you end the procedure by closing the remaining sclerotomies and then closing the conjunctiva and tenons over the electronics and scleral buckle. From there, the critical step is to take the time to tack and make sure the array is very flat on the retina.

Mark Humayun: I think the best way to tell that is if you get folding in the retina. So I really look for that. If you push it too hard, you get retinal folds around the edge of the array—then you just pull back on the tack a bit. But we spend a lot of time with any starting surgeons to be sure they understand the tacking.

The FDA requires that Argus II patients be willing and able to complete the recommended post-implant clinical follow-up, device fitting, and visual rehabilitation. Argus II has been FDA approved as a humanitarian-use device, an approval pathway limited to devices that treat or diagnose fewer than people in the US each year.

Mike Jumper: For an experienced surgeon, is this a 2-hour procedure? After a few procedures, I can complete one in just under 2 hours. For the first operation, I would obviously allow more time. You have to suture the sclerotomies so there is no leakage—ie, the eye is watertight.

Mark Humayun: Thanks for bringing that up. Actually, we use a thin layer of pericardium over the cable of the electrode array where it comes out of the sclerotomy into the electronic can. Mike Jumper: Where will the training for this new technique be available? Mark Humayun: We have developed a training program which is available from Second Sight, and they also have a mock surgery setup.

Typically, the training is done at the implanting center the day prior to the first case—and it takes about 1 to 2 hours. A number of stories highlighted the case of year-old Kathy Blake, who is Dr. The Argus II restored her sight after having been blind for 23 years. Bazell R. Gift of Sight. February 14, Benitez G. Belluck P. Device offers partial vision for the blind. The New York Times. The FDA does require training of both the hospital staff and the surgeon prior to the first case.

In addition to the training program from Second Sight, a surgeon experienced in Argus II implantation will be present at the first case.

Mike Jumper: What kind of rehab do you think the person who receives one of these commercial products will receive? Will there be pretty intensive rehab for weeks or months? How do you see it happening? Mark Humayun: Rehab time has lessened considerably.

In the latest patients in Europe, it's taken about 2 months. Today, rehab is typically performed after the device has been programmed, and most patients go through a rehab program that involves 10 to 15 sessions of about 1 hour each.

These sessions tend to be spread out over the first 3 months post-operatively. The occupational or low-vision therapist works with the patient to teach basic skills, identify important goals, and help the patient achieve them.

Mike Jumper: What is the treatment regimen after the patient completes post-op rehab? Mark Humayun: Once a patient finishes post-op rehab, the sessions are once quarterly. Patients do get their settings looked at, and of course we want to look at the patients once quarterly as well.