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55-557: Argus retinal prosthesis , also known as a bionic eye , is an electronic retinal implant manufactured by the American company Second Sight Medical Products. It is used as a visual prosthesis to improve the vision of people with severe cases of retinitis pigmentosa . The Argus II version of the system was approved for marketing in the European Union in March 2011, and it received approval in

110-414: A hybrid form of vision. In this case the implant would supplement the remaining peripheral vision with central vision information. There are two main types of retinal implants by placement. Epiretinal implants are placed in the internal surface of the retina, while subretinal implants are placed between the outer retinal layer and the retinal pigment epithelium . Epiretinal implants are placed on top of

165-413: A meeting with the two of them and Robert Greenberg, who worked at Mann's foundation. Greenberg had previously worked on retinal prosthetics as a graduate student at Johns Hopkins University , wrote the business plan, and was appointed as CEO of the new company when it was launched. Greenberg led the company as CEO through 2015 (and was chairman of the board through 2018). The first version of the prosthesis,

220-620: A new building on USC's campus in 1985 to provide clinical facilities for USC's ophthalmology faculty. In 2011, USC and the Doheny Eye Institute fell into a dispute over renovations, permits, and other matters related to the building, which led to litigation. In 2013, the Doheny Eye Institute ended its relationship with USC and entered into an exclusive, long-term affiliation with University of California Los Angeles Ronald E. Smith served as department chairman from 1995 to 2013, and left USC to follow Doheny, and became vice chair of

275-498: A patient must have an intact ganglion cell layer in order to be a candidate for a retinal implant. This can be assessed non-invasively using optical coherence tomography (OCT) imaging . Other factors, including the amount of residual vision, overall health, and family commitment to rehabilitation, are also considered when determining candidates for retinal implants. In subjects with age-related macular degeneration, who may have intact peripheral vision, retinal implants could result in

330-427: A smaller implant and simpler upgrades without additional surgery. The external electronics provides full control over the image processing for each patient. Epiretinal implants directly stimulate the retinal ganglion cells, thereby bypassing all other retinal layers. Therefore, in principle, epiretinal implants could provide visual perception to individuals even if all other retinal layers have been damaged. Since

385-514: A subretinal implant and evaluate the design in a clinical trial. Initial reports indicated that the implantation procedure was safe, and all subjects reported some perception of light and mild improvement in visual function. The current version of this device has been implanted in 10 patients, who have each reported improvements in the perception of visual details, including contrast, shape, and movement. Retina Implant AG in Germany has also developed

440-402: A subretinal implant in place is relatively simple, as the implant is mechanically constrained by the minimal distance between the outer retina and the retinal pigment epithelium. A subretinal implant consists of a silicon wafer containing light sensitive microphotodiodes , which generate signals directly from the incoming light. Incident light passing through the retina generates currents within

495-519: A subretinal implant, which has undergone clinical testing in nine patients. Trial was put on hold due to repeated failures. The Retina Implant AG device contains 1500 microphotodiodes, allowing for increased spatial resolution, but requires an external power source. Retina implant AG reported 12 months results on the Alpha IMS study in February 2013 showing that six out of nine patients had a device failure in

550-425: Is also a risk of bacterial infection from the implanted cables that connect the implant to the signal processor. The implantation procedure takes several hours, with the person receiving the implant under general anaesthesia . The surgeon removes the vitreous humor and any membranes on the retina where the implant will be placed. The implant is attached to the surface of the retina with a tack. The cables connecting

605-489: Is also more straightforward, as it places the stimulating array directly adjacent to the damaged photoreceptors. By relying on the function of the remaining retinal layers, subretinal implants allow for normal inner retinal processing, including amplification, thus resulting in an overall lower threshold for a visual response. Additionally, subretinal implants enable subjects to use normal eye movements to shift their gaze. The retinotopic stimulation from subretinal implants

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660-443: Is also required to provide power to the implant via radio-frequency induction coils or infrared lasers. The real-time image processing involves reducing the resolution, enhancing contrast, detecting the edges in the image and converting it into a spatio-temporal pattern of stimulation delivered to the electrode array on the retina. The majority of electronics can be incorporated into the associated external components, allowing for

715-704: Is available in Germany, France, Italy, and UK. Interim results on 30 patients long term trials were published in Ophthalmology in 2012. Argus II received approval from the US FDA on April 14, 2013 FDA Approval . Another epiretinal device, the Learning Retinal Implant, has been developed by IIP technologies GmbH, and has begun to be evaluated in clinical trials. A third epiretinal device, EPI-RET, has been developed and progressed to clinical testing in six patients. The EPI-RET device contains 25 electrodes and requires

770-420: Is inherently more accurate, as the pattern of incident light on the microphotodiodes is a direct reflection of the desired image. Subretinal implants require minimal fixation, as the subretinal space is mechanically constrained and the retinal pigment epithelium creates negative pressure within the subretinal space. The main disadvantage of subretinal implants is the lack of sufficient incident light to enable

825-431: Is somewhat limited and the majority of spatial resolution simulation experiments have been conducted in normal controls. It remains unclear whether the low level vision provided by current retinal implants is sufficient to balance the risks associated with the surgical procedure, especially for subjects with intact peripheral vision. Several other aspects of retinal implants need to be addressed in future research, including

880-475: Is surgically implanted on the surface of the person's retina and tacked into place. The implant consists of 60 electrodes , each 200 microns in diameter. The resolution of the 6 dot by 10 dot rectangular grid image (produced by the 6 by 10 array of 60 electrode, of which 55 are enabled ) in a person's vision is very low relative to normal visual acuity. This allows visual detection of edges of large areas of high contrast, such as door frames and sidewalks, to give

935-733: Is worth to note high-density stimulation is not equal to high visual acuity (resolution), which requires a lot of factors in both hardware (electrodes and coatings) and software (stimulation strategies based on surgical results). Clinical reports to date have demonstrated mixed success, with all patients report at least some sensation of light from the electrodes, and a smaller proportion gaining more detailed visual function, such as identifying patterns of light and dark areas. The clinical reports indicate that, even with low resolution, retinal implants are potentially useful in providing crude vision to individuals who otherwise would not have any visual sensation. However, clinical testing in implanted subjects

990-608: The California Institute for Regenerative Medicine to conduct a clinical trial in which the use of embryonic stem cells to treat age-related macular degeneration will be tested. In 2014-15, USC Eye Institute and USC Department of Ophthalmology retained the No. 9 spot in the national rankings of “Best Hospitals” by U.S. News & World Report . The faculty of the USC Department of Ophthalmology has earned Top 10 recognition by

1045-449: The LogMAR scale and improvements ranged from just under 2.9 to 1.6 LogMAR – the equivalent of 20/1262 reading ability. 96% of the subjects were better able to identify a white square on a black computer screen; 57% were more able to determine the direction in which a white bar moved across a black computer screen. With the device switched on, about 60% were able to accurately walk to a door that

1100-438: The crystalline lens to be replaced with a receiver chip. All subjects have demonstrated the ability to discriminate between different spatial and temporal patterns of stimulation. Subretinal implants sit on the outer surface of the retina, between the photoreceptor layer and the retinal pigment epithelium, directly stimulating retinal cells and relying on the normal processing of the inner and middle retinal layers. Adhering

1155-405: The occipital cortex could be used to create visual percepts, phosphenes . The first application of an implantable stimulator for vision restoration was developed by Drs. Brindley and Lewin in 1968. This experiment demonstrated the viability of creating visual percepts using direct electrical stimulation, and it motivated the development of several other implantable devices for stimulation of

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1210-517: The ARGUS device are being developed with increasingly dense electrode arrays, allowing for improved spatial resolution. The most recent ARGUS II device contains 60 electrodes, and a 200 electrode device is under development by ophthalmologists and engineers at the USC Eye Institute. The ARGUS II device received marketing approval in February 2011 (CE Mark demonstrating safety and performance), and it

1265-623: The Argus I, was clinically tested on six people starting in 2002. The second version, the Argus II, was designed to be smaller and easier to implant, and was co-invented by Mark Humayun of the USC Eye Institute , who had been involved in the clinical testing of the Argus I. The Argus II was first tested in Mexico in 2006, and then a 30-person clinical trial was conducted in 10 medical centers across Europe and

1320-580: The Argus II launched in the United States in February 2013, Second Sight announced that it would be priced at around $ 150,000, excluding the cost of surgery and usage training. In August 2013, Second Sight announced that reimbursement payments had been approved for the Argus II for blind Medicare recipients in the United States. A trial in England funded by NHS England for ten patients began in 2017. In 2020, Second Sight stopped providing technical support for

1375-496: The Argus, as well as for the successor device, Argus II, and for the brain implant, Orion; an investigation by IEEE Spectrum revealed that users risk – and in some cases, have already experienced – a return to blindness. Second Sight merged with Nano Precision Medical in August 2023 with a commitment to provide technical support for the Argus II. Retinal implant Foerster was the first to discover that electrical stimulation of

1430-603: The US in Feb 2013 and in Europe in Feb 2011, becoming the first approved implant. The device may help adults with RP who have lost the ability to perceive shapes and movement to be more mobile and to perform day-to-day activities. The epiretinal device is known as the Retina Implant and was originally developed in Germany by Retina Implant AG . It completed a multi-centre clinical trial in Europe and

1485-476: The US in February 2013 under a humanitarian device exemption . The Argus II system costs about US$ 150,000, excluding the cost of the implantation surgery and training to learn to use the device. Second Sight had its IPO in 2014 and was listed on Nasdaq . Production and development of the prosthesis was discontinued in 2020, but taken over by the company Cortigent in 2023. The Argus II is specifically designed to treat people with retinitis pigmentosa . The device

1540-724: The United States. The Argus II received approval for commercial use in the European Union in March 2011. In February 2013, the FDA approved the Argus II under a humanitarian device exemption , authorizing its use for up to 4,000 people in the US per year. The Argus II was initially available at a limited number of clinics in France , Germany , Italy , the Netherlands , the United Kingdom and Saudi Arabia , at an EU market price of US$ 115,000. When

1595-475: The ability to perform basic visual tasks, such as shape recognition and motion detection. The quality of vision expected from a retinal implant is largely based on the maximum spatial resolution of the implant. Current prototypes of retinal implants are capable of providing low resolution, pixelated images. "State-of-the-art" retinal implants incorporate 60-100 channels, sufficient for basic object discrimination and recognition tasks. However, simulations of

1650-689: The department at UCLA. Mark S. Humayun took over as chair of the Department of Ophthalmology at the Keck School of Medicine of USC in November 2013, and in February 2014, Rohit Varma was appointed director of the USC Eye Institute. In April 2016 it received a $ 25 million gift from Edward P. Roski and his wife, Gayle, and was renamed in their honor. Members of the Institute have made contributions to vision research, some prior to arriving at USC such as two of

1705-449: The department. Stephen J. Ryan was recruited in 1974 and served as the department’s first professor and chairman through 1995. In 1975, the Doheny Eye Institute allied with USC's Ophthalmology department under Ryan and relocated to the USC campus. The alliance "provided Dr. Ryan the opportunity to recruit and build the institute’s department from the ground up. Thus began the transformation of

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1760-475: The functionality provided by low resolution visual feedback , but also the ability for subjects to adapt and improve over time. However, these experiments are based merely on simulations of low resolution vision in normal subjects, rather than clinical testing of implanted subjects. The number of electrodes necessary for reading or room navigation may differ in implanted subjects, and further testing needs to be conducted within this clinical population to determine

1815-419: The implant to the processor are run through the pars plana , a region near where the iris and sclera touch. The Argus implant's primary external element is a digital camera mounted on eyeglass frames, which obtains images of the user's surroundings; signals from the camera are transmitted wirelessly to a computerised image processor. The processor is in turn connected by cables to the implant itself, which

1870-426: The implant. Subretinal implants require intact inner and middle retinal layers, and therefore are not beneficial for retinal diseases extending beyond the outer photoreceptor layer. Additionally, photoreceptor loss can result in the formation of a membrane at the boundary of the damaged photoreceptors, which can impede stimulation and increase the stimulation threshold. Optobionics was the first company to develop

1925-513: The implanted microphotodiodes array. However, some subretinal implants require power from external circuitry to enhance the image signal. A subretinal implant is advantageous over an epiretinal implant in part because of its simpler design. The light acquisition, processing, and stimulation are all carried out by microphotodiodes mounted onto a single chip, as opposed to the external camera, processing chip, and implanted electrode array associated with an epiretinal implant. The subretinal placement

1980-452: The individual the capability to navigate in their environment more safely. The implant's manufacturer, Second Sight Medical Products, was founded in Sylmar , California, in 1998, by Alfred Mann, Samuel Williams, and Gunnar Bjorg. Williams, an investor in a cochlear implant company operated by Mann, approached Mann about founding a company to develop a similar product for the eye, and Mann called

2035-410: The institute into one of the top university based ophthalmic teaching, clinical, and research centers....Dr. Ryan built Doheny into a respected institution. In 2011 alone, Doheny scientists received $ 21.8 million in federal and state grants and published more than 180 scientific papers." All of the Doheny Eye Institute 's doctors were appointed as USC faculty members. The Doheny Eye Institute built

2090-497: The inventors of optical coherence tomography , Carmen A. Puliafito (as of 2007, Dean of the Keck School of Medicine) and David Huang, who did his residency at USC. Dr. Mark Humayun, who joined the faculty of the Keck School of Medicine of USC in 2001, was a co-inventor of a retinal prosthesis that became the basis for the formation of the company, Second Sight, in 1998. Their first-generation implant had 16 electrodes and

2145-413: The long term stability of the implants and the possibility of retinal neuron plasticity in response to prolonged stimulation. The Manchester Royal Infirmary and Prof Paulo E Stanga announced on July 22, 2015, the first successful implantation of Second Sight's Argus II in patients with severe Age Related Macular Degeneration. These results are very impressive as it appears that the patients integrate

2200-401: The microphotodiodes to generate adequate current. Thus, subretinal implants often incorporate an external power source to amplify the effect of incident light. The compact nature of the subretinal space imposes significant size constraints on the implant. The close proximity between the implant and the retina also increases the possibility of thermal damage to the retina from heat generated by

2255-443: The microphotodiodes, which directly inject the resultant current into the underlying retinal cells via arrays of microelectrodes . The pattern of microphotodiodes activated by incident light therefore stimulates a pattern of bipolar , horizontal , amacrine , and ganglion cells, leading to a visual perception representative of the original incident image. In principle, subretinal implants do not require any external hardware beyond

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2310-433: The nerve fiber layer has similar stimulation threshold to that of the retinal ganglion cells, axons passing under the epiretinal electrodes are stimulated, creating arcuate percepts, and thereby distorting the retinotopic map. So far, none of the epiretinal implants had light-sensitive pixels, and hence they rely on external camera for capturing the visual information. Therefore, unlike natural vision, eye movements do not shift

2365-547: The nine months post implant Proceedings of the royal society B , and that five of the eight subjects reported various implant-mediated visual perceptions in daily life. One had optic nerve damage and did not perceive stimulation. The Boston Subretinal Implant Project has also developed several iterations of a functional subretinal implant, and focused on short term analysis of implant function. Results from all clinical trials to date indicate that patients receiving subretinal implants report perception of phosphenes, with some gaining

2420-448: The required spatial resolution for specific visual tasks. Simulation results indicate that 600-1000 electrodes would be required to enable subjects to perform a wide variety of tasks, including reading, face recognition, and navigating around rooms. Thus, the available spatial resolution of retinal implants needs to increase by a factor of 10, while remaining small enough to implant, to restore sufficient visual function for those tasks. It

2475-478: The residual vision and the artificial vision. It potentially opens the use of retinal implants to millions of patients with AMD. USC Eye Institute The USC Gayle and Edward Roski Eye Institute , part of Keck School of Medicine of USC , is a center for ophthalmic care, research and education located in downtown Los Angeles , California. It has subsidiary clinics in Pasadena , Beverly Hills and Arcadia . It

2530-629: The resultant pixelated images assume that all electrodes on the implant are in contact with the desired retinal cell; in reality the expected spatial resolution is lower, as a few of the electrodes may not function optimally. Tests of reading performance indicated that a 60-channel implant is sufficient to restore some reading ability, but only with significantly enlarged text. Similar experiments evaluating room navigation ability with pixelated images demonstrated that 60 channels were sufficient for experienced subjects, while naïve subjects required 256 channels. This experiment, therefore, not only demonstrated

2585-447: The retinal ganglion cells encoding different features of the image. The first epiretinal implant, the ARGUS device, included a silicon platinum array with 16 electrodes. The Phase I clinical trial of ARGUS began in 2002 by implanting six participants with the device. All patients reported gaining a perception of light and discrete phosphenes, with the visual function of some patients improving significantly over time. Future versions of

2640-412: The retinal surface, above the nerve fiber layer, directly stimulating ganglion cells and bypassing all other retinal layers. Array of electrodes is stabilized on the retina using micro tacks which penetrate into the sclera. Typically, external video camera on eyeglasses acquires images and transmits processed video information to the stimulating electrodes via wireless telemetry . An external transmitter

2695-438: The transmitted image on the retina, which creates a perception of the moving object when person with such an implant changes the direction of gaze. Therefore, patients with such implants are asked to not move their eyes, but rather scan the visual field with their head. Additionally, encoding visual information at the ganglion cell layer requires very sophisticated image processing techniques in order to account for various types of

2750-534: The visual pathway, including retinal implants. Retinal stimulation devices, in particular, have become a focus of research as approximately half of all cases of blindness are caused by retinal damage. The development of retinal implants has also been motivated in part by the advancement and success of cochlear implants , which has demonstrated that humans can regain significant sensory function with limited input. The Argus II retinal implant , manufactured by Second Sight Medical Products received market approval in

2805-399: Was 20 feet away, as opposed to only 5% with the device switched off; 93% had no change in their perception of light. Among the thirty subjects in the clinical trial, there were nine serious adverse events recorded, including lower than normal intraocular pressure , erosion of the conjunctiva , reopening of the surgical wound , inflammation inside the eye , and retinal detachments . There

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2860-488: Was allied with the Doheny Eye Institute from 1975 until 2013, when Doheny allied with University of California Los Angeles . Ophthalmology at the Keck School of Medicine of USC attained departmental status in 1974 and opened its first building on the USC Health Sciences Campus in 1975. Although an ophthalmology residency program existed at USC prior to that time, there were no full-time faculty members in

2915-450: Was approved with data from a single-arm clinical trial that enrolled thirty people with severe retinitis pigmentosa; the longest follow-up on a trial subject was 38.3 months. People in the trial received the implant in only one eye and tests were conducted with the device switched on, or switched off as a control. With the device switched on, about 23% of the subjects had improvements in their ability to see ; all had been at 2.9 or higher on

2970-420: Was awarded a CE Mark in 2013, making it the first wireless epiretinal electronic device to gain approval. Optimal candidates for retinal implants have retinal diseases, such as retinitis pigmentosa or age-related macular degeneration. These diseases cause blindness by affecting the photoreceptor cells in the outer layer of the retina, while leaving the inner and middle retinal layers intact. Minimally,

3025-461: Was implanted in 6 subjects by Humayun at University of Southern California between 2002 and 2004; Humayan has participated in subsequent clinical trials as well. Ophthalmologist George Baerveldt , while he was at USC, developed the most commonly used glaucoma implant in the world, the Baerveldt glaucoma implant . In December 2013, David Hinton and Mark S. Humayun won a $ 19 million grant from

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