Development of an extraocular retinal prosthesis: Evaluation of stimulation parameters in the cat

Probing the functional impact of sub-retinal prosthesis

“…Charge balanced biphasic pulses, delivered in voltage or current mode injection, are of common use in human (Ahuja and Behrend, 2013; Fujikado et al, 2007; Humayun et al, 2012; Klauke et al, 2011; Nanduri et al, 2012; Rizzo, 2003; Shepherd et al, 2013; Stingl et al, 2013; Wilke et al, 2011; Zrenner, 2013; Zrenner et al, 2010) or animal (Chowdhury et al, 2008; Cicione et al, 2012; Eckhorn et al, 2006; Eger et al, 2005; Elfar et al, 2009; Matteucci et al, 2013; Nadig, 1999; Schanze et al, 2003; Walter et al, 2005; Wong et al, 2009) studies of prosthetic vision. In the literature, we observed a large consensus concerning the use of cathodic pulse first for epiretinal stimulation (Ahuja and Behrend, 2013; Eckhorn et al, 2006; Eger et al, 2005; Elfar et al, 2009; Fried et al, 2006; Nanduri et al, 2012; Schanze et al, 2003; Walter et al, 2005) although not for subretinal, suprachoroidal and extraocular approaches (Chowdhury et al, 2008; Cicione et al, 2012; Eckhorn et al, 2006; Fujikado et al, 2007; Matteucci et al, 2013; Stingl et al, 2013; Wilke et al, 2011; Wong et al, 2009).…”

“…In the literature, we observed a large consensus concerning the use of cathodic pulse first for epiretinal stimulation (Ahuja and Behrend, 2013; Eckhorn et al, 2006; Eger et al, 2005; Elfar et al, 2009; Fried et al, 2006; Nanduri et al, 2012; Schanze et al, 2003; Walter et al, 2005) although not for subretinal, suprachoroidal and extraocular approaches (Chowdhury et al, 2008; Cicione et al, 2012; Eckhorn et al, 2006; Fujikado et al, 2007; Matteucci et al, 2013; Stingl et al, 2013; Wilke et al, 2011; Wong et al, 2009). It has been shown in vitro (Jensen et al, 2005) that the use of single cathodic pulse lowers the threshold of retinal ganglion cells (RGCs), lowers the latency of inner retina mediated RGCs response and targets more specifically RGCs cell bodies when compared to anodal pulses.…”

“…To improve the resolution and efficiency of retinal prosthesis, it is therefore necessary to launch appropriate models that allow probing precisely and quantitatively the functional impact of prosthetic activation. Pioneering animal studies have proposed to use cortical recordings to explore the efficiency of various patterns of retinal electrical stimulation (Chowdhury et al, 2008), including current steering methods (Jepson et al, 2014a; Matteucci et al, 2013) or the effect of the return electrode configuration (Cicione et al, 2012; Matteucci et al, 2013; Wong et al, 2009) and studied the temporal aspect of prosthetic vision (Elfar et al, 2009; Fransen et al, 2014; Jepson et al, 2014a, 2013, 2014b; Nadig, 1999; Schanze et al, 2003; Sekirnjak et al, 2008; Wilms et al, 2003). However, most were not designed to characterize and calibrate the functional activation of the visual system (Chowdhury et al, 2008; Eger et al, 2005; Mandel et al, 2013; Nadig, 1999; Schanze et al, 2003; Walter et al, 2005; Wong et al, 2009) nor probed the functional impact of implants through systematic comparison with visual activation (Chowdhury et al, 2008; Cicione et al, 2012; Eger et al, 2005; Fransen et al, 2014; Mandel et al, 2013; Matteucci et al, 2013; Schanze et al, 2003; Wong et al, 2009).…”

Electronic restoration of vision in those with photoreceptor degenerations

“…Their study showed electrically evoked potentials in the visual cortex following electrical stimulation of the rabbit retina. 64 A further study 65 showed electrically evoked potentials recorded in the cat visual cortex following episcleral stimulation with one, two and three millimetre diameter electrodes. These electrodes are quite large and even though the surgery offers minimal risks, this approach is unlikely to provide highresolution vision.…”

Electronic Approaches to Restitute Vision in Patients with Neurodegenerative Diseases of the Retina

“…However, this approach has not been pursued further, probably due to the rather extensive surgery and the low spatial resolution. Also optic nerve stimulation by implanting microelectrodes onto the head of the optic nerve [51] and extraocular electrical stimulation [52] were tested. At the University of Wisconsin a device has been developed that delivers spatially structured input to the tongue via a matrix of electrodes worn inside the mouth [53].…”