[Vision engineering--photoelectric dye-based retinal prostheses: Okayama University model].
Patients with retinitis pigmentosa lose photoreceptor cells by genetic abnormalities and hence become blind. Neurons such as bipolar cells and ganglion cells still remain alive even in the retina of these patients, and ganglion cells send axons to the brain as the optic nerve. The replacement of dead photoreceptor cells with something artificial is the basic concept of retinal prostheses. The remaining retinal neurons can be stimulated by either electric current or electric potential. Photodiode array and electrode array are two main ways to stimulate retinal neurons as retinal prostheses. These retinal prostheses have problems such as low sensitivity and requiring outer electric sources (batteries). To overcome the problems, we are developing photoelectric dye-based retinal prostheses which absorb light and convert photon energy to electric potentials. The prototype, photoelectric dye-coupled polyethylene film, could generate intracellular calcium elevation in photoreceptor-lacking retinal tissues and also in cultured retinal neurons. The photoelectric dye-based retinal prostheses are thin and soft, and therefore, a sheet of the film in a large size, corresponding to wide visual field, can be inserted into the vitreous and then to the subretinal space through a small opening by rolling up the film. After the production control and the quality control have been established, clinical trials of the photoelectric dye-based retinal prostheses would be planned in concordance with the Drugs and Medical Devices Law to prove the safety and the efficacy.
Matsuo
Toshihiko
T
Department of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama, Japan.
D005074:Evoked Potentials, Visual; D006801:Humans; D019736:Prostheses and Implants; D011474:Prosthesis Design; D012160:Retina; D014786:Vision Disorders / Q000628:therapy