Abstract:

The size of the blind population in 2015 was estimated to be approximately 36 million (Bourne et al., 2017). According to the predictions by Bourne and co-workers, the number of the visually impaired is expected to reach nearly 100 million by 2050. Although some of these diseases can be treated, to date, some other eye conditions such as retinitis pigmentosa (RP), an inherited degenerative condition of the photoreceptors, have no treatment except electrical stimulation of the surviving neurons of the visual system. This therapy, delivered via a visual prosthesis, relies on an electrode array, implanted in close proximity to the target neurons, able to deliver a series of electrical impulses that activate these cells thus eliciting a visual sensation (Lewis et al., 2016). These electrodes can be implanted in the retina (three approaches exist: epiretinal, subretinal and suprachoroidal implants), the optic nerve, the lateral geniculate nucleus or the visual cortex. The medical device industry has spotted the opportunity and several companies have already obtained approval for commercialisation of their devices in the US and the European markets. However, the niche for these technologies may be soon occupied by new promising therapies based on a biological approach.