A Literature Review of the Development Trends of Visual Neural Protheses

Abstract

According to a systemic review of population-based data sets relevant to global vision impairment and or blindness between 1980 in 2015, there is an estimated 36 million people who suffer from blindness [4]. An additional 405.1 million people with mild to severe visual impairment [4]. Visual impairment of any degree and its growing prevalence are not a new issue. However, recent advancements in neural protheses, such as cochlear implants that aid those who are hearing impaired, leading researchers to turn to visual neural protheses. Visual neural prostheses focus on the concept of artificially inducing vision by using our current understanding of electrical stimulation, visual pathways, and visual sensations. Therefore, all visual protheses focus on creating an artificial sense of vision through the electrical activation of neurons belonging to the visual system of the body [2]. There are a variety of approaches researchers have taken to accomplish this, the approaches differ in the aspects of the visual system they attempt to replace. As of 2019 they are primarily four approaches that encompass most neural prosthetics. Those that focus on the retina, optical nerve, cortical region of the brain, and or the lateral geniculate nucleus (LGN) within the thalamus [2][3]. The most prominent of which is the retina neural prosthetic, having multiple current implants such as the Argus II electronic epiretinal device, this is due to its extracranial location and simpler organization compared to other methods [3][5]. However, the retinal approach is not without faults of its own such as unwanted electrochemical reactions and low resolution. Therefore, in this paper the four approaches of visual neural prostheses will be examined to provide a greater insight into the field.