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Visual function after implantation of the subretinal Alpha IMS device in 26 blind retinitis pigmentosa patients. The Subretinal Approach. Photodiodes and electrodes correspond to the retinotopic correct localization Remaining retinal network can be utilized
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Visual function after implantation of the subretinal Alpha IMS device in 26 blind retinitis pigmentosa patients
The Subretinal Approach • Photodiodes and electrodes correspond to the retinotopic correct localization • Remaining retinal network can be utilized • Fixation of the chip is easier • Eye movement helps localizing objects • There are no visible parts of the implant outside the body
Implantation surgery (extraocular part):Receiver and subcutaneous cable placed first. Implant passed through lateral orbital wall into subconjunctival space
Implantation surgery (Intraocular part): 1) Vitrectomy 2) Subretinal bleb raised under sceral flap 3) Implant passed through choroid into subretinal space; advanced until it is placed under fovea 4) Foil and cables sutured outside scleral flap. Scleral flap sutured shut.
Receiver Coil Transmitter Coil Transmitter Coil magnetically attached The Subretinal Implant Alpha-IMS (Retina Implant AG, Reutlingen) Rechargeable Battery Pack
German Subretinal Implant Studies 3 Clinical Trials • 2005-2009 Pilot studysingle centre • wire bound implant (11 Patients.) • Zrenner et al. ProcBiol Sci. 2011 May 22;278(1711):1489–97 • Main study Module 1, single centre2010-2011: • wireless implantAlpha IMS (9 Patients) • Stingl et al. Proc. R. Soc. B 2013 280, 20130077, 20 February 2013 • III. Main study Module 2, multicentre 2011- ongoing: • wireless implant Alpha IMS, (17 [+3] Patients ) Total: 40 patients
Multi Center Study (Module 1&2): 29 Patients • Single Center:Tübingen (9) • Multicenter:Tübingen (2), 1 reimplant • Oxford (6) • London (3) +1 Dresden (1) +1 Budapest (1)+1 Singapore (2) Hong Kong (2) Module 1 Module 2 • 26 (at abstract submission) • + 3 patients
Summary • At present, electronic implants are the only option for patients blind from hereditary retinal diseases to regain some vision, in the best case, up to 20/550 • Subretinal implantation surgery with the Alpha-IMS device appears to have an acceptable safety profile • Psychophysical testing and self-reported outcomes indicate restoration of useful vision in a majority of patients. • Technically there is room for improvement for electronic implants for use in daily life in terms of visual resolution, contrast sensitivity, visual field, long term stability, practicality. • Clinical trials continue with a slightly modified implant designed for long term durabiltiy. • The Alpha-IMS implant has a CE mark for commercial use in Europe (Jul 2013)