OBJECTIVE: To evaluate feasibility of restoration of central vision in patients with age-related macular degeneration using a wireless photovoltaic subretinal implant. In particular, to assess safety of sub- retinal implantation and quality of prosthetic vision in patients with geographic atrophy.
MATERIAL-METHODS: A prospective study in 5 patients with visual acuity ≤20/400 due to geographic atrophy of at least 3 optic discs diameters and no foveal perception. Wireless photovoltaic chip
(PRIMA, Pixium Vision) is 2x2mm in size,30μm in thickness, containing 378 pixels of 100μm in width. Each pixel converts pulsed near-infrared light (880nm) projected from video-goggles into electric current to stimulate nearby
neurons in the inner retina nuclear layer. Several surgical techniques used, varying in anesthesia (local vs. general) and retinal reattachment (gas vs. oil)
RESULTS: In all patients, surgery lasted approximately 2 hours, chip was successfully implanted under the macula and remains stable, with a follow-up extending now to 11 months in first patient. In 3
patients chip was placed into a desired position-centrally and close to the inner retina. In 2 patients the implant ended up in suboptimal positions–one in the choroid and another off-center. All 5 patients perceive white-yellow patterns with adjustable brightness, in retinotopically correct locations within previous scotomata. No decrease in natural visual acuity was observed in any patient. All 4 patients with subretinal chip placement correctly identify bar orientation, with 93.5+/-3.8% accuracy. Out of them, all 3 patients with central placement of the implant demonstrated visual acuity with Landolt C test in the range of 20/460-20/550,which is just 15-35% below the theoretical resolution limit for this pixel size (20/400).Patients are now being tested in letter recognition, reading, and other visual tasks.
CONCLUSIONS: Wireless chip PRIMA can be safely implanted under the atrophic macula in patients with geographic atrophy and restore central visual perception with acuity close to the theoretical limit of the implant. Implantation did not reduce the natural residual visual acuity of the patients. Implants with smaller pixels are being developed.
Sanford University (USA)
E. J. Chichilnisky is Professor of Neurosurgery and Ophthalmology, in the Hansen Experimental Physics Laboratory at Stanford University. His research is focused on how the retina processes visual information and transmits this information to the brain. A key area of interest is how the cellular circuitry of the retina performs the neural computations essential for vision.
Rotterdam Eye Hospital (Netherlands)
In the Rotterdam Eye Hospital Jan van Meurs is director of the residency program, recently scientific advisor of the research institute, and in 2005 was appointed professor in Ophthalmology, specifically vitreoretinal surgery, at the Erasmus University. His research and experience in Ophthalmology spans across Australia, Indonesia, Curaçao, and USA. He has been involved in a cataract charity program and more recently a vitreoretinal cooperation program in Indonesia. Jan helps organizing the annual meeting of the Dutch Ophthalmological Society and is board member of EURETINA, and he was elected President in 2016. He combines clinical work with research interests in retinal detachments, PVR, pharmacokinetics, RPE-transplantation and endophthalmitis
University of Rome (Italy)
Prof. Andrea Cusumano is Research Professor of Ophthalmology at the University of Rome Tor Vergata, APL Professor at the University of Bonn and Adjunct Associate Professor at the Weill Cornell Medical College of New York. As a vitreoretinal surgeon and expert in ultrastructural analysis, he is contributing to the implementation of innovative laser and surgical techniques as well as to the development of new therapies for the treatment of hereditary retinal diseases and AMD. He is also Founder and President of the Macula & Genoma Foundation Onlus.</p>
Moorfields Eye Hospital (UK)
Dr Mahi Muqit PhD FRCOphth is a Consultant Vitreoretinal Surgeon at Moorfields Eye Hospital, and Honorary Clinical Lecturer at the Institute of Ophthalmology, University College London. He has subspecialist expertise in complex cataract surgery, medical retina, and vitreoretinal surgery. He works with Helen Keller International (HKI) focused on training and setting up diabetic eye screening programmes in Bangladesh and Indonesia. The UK research team is recipients of Seeing Is Believing Innovation Awards for new international online training systems in diabetic retinopathy. He is amember of the Diabetic Retinopathy Working Group International Agency for the Prevention of Blindness (IAPB); a member of the Diabetic Eye Care committee for the ICO;and,Specialist Adviser to the National Institute for Health and Care Excellence (NICE) for the Interventional Procedures Programme in the UK.
IMO, Institute of Ocular Microsurgery (Spain)
Co-founder and medical director of IMO (institute of Ocular Microsurgery), professor at the Autonomous University of Barcelona, and director of the Scientific Board at the European School for Advanced Studies in Ophthalmology (ESASO), Switzerland. Surgeon and ophthalmologist specialising in the retina: retinal detachment, diabetic retinopathy, AMD, intraocular tumours, uveitis, retinal vascular disease, diabetic macular pathology, floaters and flashes. He is involved in the development of instruments and techniques for vitreoretinal surgery and clinical and surgical research trials in breakthrough innovative projects of the future, such as the retina chip, research into retinitis pigmentosa and the development of new drugs for the treatment of eye diseases. He is a permanent member of the Royal Academy of Medicine of Catalonia.
Fondation Adolphe de Rothschild Hospital (France)
Yannick Le Mer is a renowned retina surgeon, Head of Vitreo-retinal Unit at Fondation Adolphe de Rothschild Hospital in Paris. Prior to that, he was Assistant Professor in Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts from 1989-1992 as well as Chief of Staff in the Ophthalmology Department in CHU de Montreuil. Dr Le Mer was an Ophthalmologist Consultant for the Dubai Hospital, UAE and Invited Professor in Ophthalmic Hospital Jules Gonin (Lausanne, Switzerland). He is a Member of the French Ophthalmology Society, Euretina, ASRS, Deutsche Retinologische Gesellschaft, past President of Club Jules Gonin, Co-Founder and past President of CFCR.