Retinitis pigmentosa (RP) is a group of blinding eye diseases caused by hereditary retinal degeneration and a reduction in photoreceptor cells. There is no effective treatment to cure and slow down the progression of the disease. Professor Allen et al. conducted a prospective clinical study of retinal prosthesis system for retinitis pigmentosa in the U.S. The results of the study were published in the journal Ophthalmology. The study was a multicenter, single-arm, prospective clinical study of 30 eligible patients from June 2007 to August 2009 in 10 central cities in the United States and Europe. All patients had a definitive clinical diagnosis of retinitis pigmentosa with weak or no light perception in both eyes, excluding patients with retinal and optic neuritis and patients with ocular structures that could not implant the prosthetic system properly and could not tolerate surgery. The Argus II prosthesis system (Figure 1) was implanted into the eyes of subjects with worse vision. The subjects wore glasses with a small camera and a video processor that converted images into stimulation signals that were sent to an array of electrodes on the retina. Patients who had the Argus II retinal prosthesis implanted in their eyes for either one or three years showed significantly better results in planimetry and motion orientation tests than eyes without the retinal prosthesis implanted. However, patients who had the prosthetic system implanted in their eyes for 3 years had slightly worse results on both of these tests than those implanted for 1 year. In the visual acuity grating test, both eyes were compared, and the eyes without the prosthesis system, within a certain range, did not obtain a score, while the eyes with the retinal prosthesis system, whether implanted for 1 year or 3 years, were able to obtain a score of 2.9 LogMAR to 1.6 LogMAR within the same range. However, the comparison of visual function test results was not statistically significant for eyes implanted with the prosthetic system for either 1 year or 3 years. Of the 30 subjects studied, 20 patients had no serious device- or procedure-related adverse events. The other 10 patients experienced 18 serious adverse reactions, the types and incidence of which were conjunctival erosion 10.0%, hypotony 6.7%, conjunctival laceration 10.0%, endophthalmitis 10.0%, secondary implantation 6.7%, corneal clouding, aperture-origin and pull retinal detachment, retinal tears, and uveitis all at 3.3%, and keratitis and corneal dissolution at 0. The incidence of conjunctival erosion and hypotony in patients implanted with the prosthesis system for 3 years was 13.3%, which was a slight increase over the incidence of adverse events at 1 year of implantation. However, over time, patients with eyes implanted with the prosthesis system for 3 years suffered from keratitis and keratolysis in 3.3% of patients, with no significant change in the incidence of other adverse events over time. Due to the small sample size of the study, it is difficult to draw more definitive conclusions about the safety of the retinal prosthesis system in RP patients. None of the 30 patients studied had their eyes removed during the implantation of the prosthesis system and there were no other untoward events, and if the patients had any ocular conditions during the implantation of the prosthesis system, they were treated appropriately in accordance with standard ophthalmologic requirements. Prior to the use of the Argus II Retinal Prosthesis System, it is important to know whether the patient has low or no light perception in both eyes, and it is also important to consider that the use of the Argus II may result in total blindness and that there are no other therapeutic options available to assist in the management of the eye during the use of the prosthesis system. Generally, the greater concern for ophthalmic adverse effects is the potential for further loss of vision. This study is the largest and longest running clinical trial study of retinal prostheses to date. As of September 1, 2014, the longest time to implant a prosthesis was 7.2 years. The results of the study show that “Argos II” presents an acceptable risk and is a meaningful treatment for patients with total RP blindness. Moreover, the prosthesis was approved by the US FDA. Figure A shows the intraocular system of the Argos II retinal prosthesis system; B shows the external system consisting of eyeglasses and batteries.