Purpose This study evaluates the Argus™ II Retinal Prosthesis System in blind subjects with severe outer retinal degeneration. Design The study design is a single arm, prospective, multicenter clinical trial. Participants Thirty subjects were enrolled in the United States and Europe between 6 June 2007 and 11 August 2009. All subjects were followed for a minimum of six months and up to 2.7 years. Methods The electronic stimulator and antenna of the implant was sutured onto the sclera using an encircling silicone band. Next, a pars plana vitrectomy was performed and the electrode array and cable were introduced into the eye via a pars plana sclerotomy. The microelectrode array was then tacked to the epiretinal surface. Main Outcome Measures The primary safety endpoint for the trial was the number, severity, and relation of adverse events. Principal performance endpoints were assessments of visual function as well as performance on orientation and mobility tasks. Results Subjects performed statistically better with system ON vs. OFF in the following tasks: object localization (96% of subjects); motion discrimination (57%); and discrimination of oriented gratings (23%). The best recorded visual acuity to date is 20/1260. Subjects’ mean performance on Orientation and Mobility tasks was significantly better when the System was ON vs. OFF. Seventy percent of the patients did not have any serious adverse events (SAEs). The most common SAE reported was either conjunctival erosion or dehiscence over the extraocular implant and was successfully treated in all subjects except in one which required explantation of the device without further complications. Conclusions The long-term safety results of Second Sight’s retinal prosthesis system are acceptable and the majority of subjects with profound visual loss perform better on visual tasks with system than without.
Purpose The Argus® II Retinal Prosthesis System (Second Sight Medical Products, Inc., Sylmar, CA) was developed to restore some vision to patients blind from retinitis pigmentosa (RP) or outer retinal degeneration. A clinical trial was initiated in 2006 to study the long-term safety and efficacy of the Argus II System in patients with bare or no light perception due to end-stage RP. Design The study is a prospective, multicenter, single-arm, clinical trial. Within-patient controls included the non-implanted fellow eye and patients' native residual vision compared to their vision when using the System. Subjects There were 30 subjects in 10 centers in the U.S. and Europe. Methods The worse-seeing eye of blind patients was implanted with the Argus II System. Patients wore glasses mounted with a small camera and a video processor that converted images into stimulation patterns sent to the electrode array on the retina. Main Outcome Measures The primary outcome measures were safety (the number, seriousness, and relatedness of adverse events) and visual function, as measured by three computer-based, objective tests. Secondary measures included functional vision performance on objectively-scored real-world tasks. Results Twenty-four out of 30 patients remained implanted with functioning Argus II Systems at 5 years post-implant. Only one additional serious adverse event was experienced since the 3-year time point. Patients performed significantly better with the System ON than OFF on all visual function tests and functional vision tasks. Conclusions The five-year results of the Argus II trial support the long-term safety profile and benefit of the Argus II System for patients blind from RP. The Argus II is the first and only retinal implant to have market approval in the European Economic Area, the United States, and Canada.
Summary
Background
To contribute to the WHO initiative, VISION 2020: The Right to Sight, an assessment of global vision impairment in 2020 and temporal change is needed. We aimed to extensively update estimates of global vision loss burden, presenting estimates for 2020, temporal change over three decades between 1990–2020, and forecasts for 2050.
Methods
We did a systematic review and meta-analysis of population-based surveys of eye disease from January, 1980, to October, 2018. Only studies with samples representative of the population and with clearly defined visual acuity testing protocols were included. We fitted hierarchical models to estimate 2020 prevalence (with 95% uncertainty intervals [UIs]) of mild vision impairment (presenting visual acuity ≥6/18 and <6/12), moderate and severe vision impairment (<6/18 to 3/60), and blindness (<3/60 or less than 10° visual field around central fixation); and vision impairment from uncorrected presbyopia (presenting near vision
Purpose Retinitis Pigmentosa (RP) is a group of inherited retinal degenerations leading to blindness due to photoreceptor loss. A rare disease, it affects about 100,000 people in the United States. There is no cure and no approved medical therapy to slow or reverse RP. The purpose of this clinical trial was to evaluate the safety, reliability, and benefit of the Argus® II Retinal Prosthesis System (Second Sight Medical Products, Inc., Sylmar, CA) in restoring some visual function to subjects completely blind from RP. Herein, we report clinical trial results at 1 and 3 years post-implant. Design The study is a multicenter, single-arm, prospective clinical trial. Subjects There were 30 subjects in 10 centers in the U.S. and Europe. Subjects served as their own controls – i.e., implanted eye vs. fellow eye, and System ON vs. System OFF (native residual vision). Methods The Argus II System was implanted on and in a single eye (typically the worse-seeing eye) of blind subjects. Subjects wore glasses mounted with a small camera and a video processor that converted images into stimulation patterns sent to the electrode array on the retina. Main Outcome Measures The primary outcome measures were safety (the number, seriousness, and relatedness of adverse events) and visual function, as measured by three computer-based, objective tests. Results Twenty-nine out of 30 subjects remained implanted with functioning Argus II Systems at 3 years post-implant. Eleven subjects experienced a total of 23 serious device- or surgery-related adverse events. All were treated with standard ophthalmic care. As a group, subjects performed significantly better with the System ON than OFF on all visual function tests and functional vision assessments. Conclusions The three-year results of the Argus II trial support the long-term safety profile and benefit of the Argus II System for patients blind from RP. Earlier results from this trial were used to gain approval of the Argus II by the FDA and a CE Mark in Europe. The Argus II System is the first and only retinal implant to have both approvals.
While maintaining comparability with Pelli-Robson norms, the new test has improved accuracy in comparison with the Pelli-Robson chart and several other advantages that result from its smaller size.
Using lower-case fonts varying only in serif size (0%, 5%, and 10% cap height), we assessed legibility using size thresholds and reading speed. Five percentage serif fonts were slightly more legible than sans serif, but the average inter-letter spacing increase that serifs themselves impose, predicts greater enhancement than we observed. RSVP and continuous reading speeds showed no effect of serifs. When text is small or distant, serifs may, then, produce a tiny legibility increase due to the concomitant increase in spacing. However, our data exhibited no difference in legibility between typefaces that differ only in the presence or absence of serifs.
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