Development of Artificial Retinas for the Treatment of Degenerative Eye Disease and the Augmentation of Human Vision

在英国，近200万人患有某种形式的视力丧失，视力丧失的最常见原因是视网膜色素沉着症和年龄相关性黄斑变性（AMD）。AMD在英国影响超过60万人，预计到2020年将增加到近70万人。最近在美国的研究表明，发展为AMD的可能性从50岁时的2.5%增加到80岁时的14%，随着人口的平均年龄继续增加，这将是未来几代人的一个更大的问题。视力丧失通常与光感受器、视锥细胞和视杆细胞的缺失或丧失有关，而视网膜网络中的神经细胞仍保持功能。迄今为止，旨在恢复视力的人工假体目前基于光敏无机半导体器件结构，这些器件结构被植入表面上或嵌入视网膜内以刺激神经元反应。这些器件需要复杂的电路、外部电源，并且通常具有差的生物相容性和与生物组织的机械不相容性。改进的装置，其使用由聚焦的NIR输入驱动的植入的光电二极管阵列的直接光伏响应，所述NIR输入投射对视野进行采样的外部摄像机的输出。NIR输入是必需的，因为目前在这些装置中，输入环境光太暗，至少为1，000倍，以致于在植入的装置中产生足够的光电流以直接刺激神经元。因此，这些设备向患者提供单一输入，并通过视网膜网络转换为黑色和白色图像。

In the United Kingdom, almost two million people live with some form of sight loss with the most common causes of vision loss being retinal pigmentosis and age related macular degeneration (AMD). AMD affects over 600,000 people in the UK and is expected to rise to almost 700,000 in 2020. Recent studies in the USA have shown that the likelihood of developing AMD increases from 2.5% of population at age 50 to 14% at 80 years old, as the average age of the population continues to increase then this will be a larger problem for future generations.The loss of vision, in general, can be associated the absence or loss of photoreceptors, cones and rods, of the retina while the neural cells in the retinal network remain functional. To date artificial prostheses aimed at restoring vision are currently based on photoactive inorganic semiconductor device structures that have been implanted on the surface or embedded within the retina to stimulate a neuronal response.These devices require complex circuitry, external power and typically suffer from poor biocompatibility and mechanical incompatibility with biological tissue. Improved devices that use the direct photovoltaic response of an implanted array of photodiodes driven by a focussed NIR input that projects the output of an external video camera that samples the visual field.The NIR input is required as currently in these devices the input ambient light is too dim by a factor of at least 1,000 to produce sufficient photocurrent in the implanted devices to directly stimulate neurons. These devices hence give a single input to the patient and are converted to a black and white image by the retinal network.