Visual Prosthesis, Suprachoroidal, and Trans-retinal Devices

While the number of people with visual impairment is a staggering 285 million (Pascolini and Mariotti 2012), thankfully very few people are profoundly blind, and indeed most people maintain some degree of useful vision. This is particularly true in cases of prevalent degenerative disorders of the retina such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) where the typical outcome is legal blindness – defined throughout the developed world typically as being central vision less than 20/200 (6/60 in SI units) or peripheral visual fields constricted to less than 10° or 20° – as opposed to profound blindness. This is further evidenced in that AMD patients make up the majority of blind people in developed nations. Despite the introduction of ranibizumab therapy (Rosenfeld et al. 2006), AMD is still likely to remain the most common cause of legal blindness in developed countries as it addresses the neovascular component of the disease, but there is still no...