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This paper summarizes the accomplishments to date in the development of the "artificial eye" - a fully functional eye prosthesis - which we hope to use in the future as an implant in people who have lost their vision due to eye damage. The future work necessary to bring the eye project to fruition is explained, and two important tasks, which we do not yet know how to solve, are described in the hope of stimulating a broad discussion within the scientific community. The summary of the historical developments in this field is followed by our accomplishment. The components of the eye that have been developed and tested to date are color processing receptive fields, variable-focus lenses, and local and global brightness adaptation systems. A constraint imposed on the components of the artificial eye is the requirement of minimal or no power draw. Following this condition, the components were developed using mainly passive, photonic properties of nonlinear optical materials. Color receptive fields are fabricated of photo-luminescent concentrators and photovoltaic detectors set in a multilayer stacked system allowing for color processing. Local and global adaptation is accommodated using the photochromic properties of some nonlinear optical materials. A variable focus lens is made of transparent elastic membranes filled with a refractive liquid, and focal length is changed by radial stretching. This modification to the lens was made to accommodate cataract patients. Two important aspects of the research, which are yet unsolved, include proper encoding of visual signals before transmission to the brain and methods for physical transmission of the encoded signals to the visual cortex.
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