argus ii retinal prosthesis system - better vision rp study

Conditions: Retinitis Pigmentosa

Summary: the study is conducted to evaluate the safety and benefit of the argus ii system in a selected patient population with advanced retinitis pigmentosa who have a measurable central residual visual field smaller than or equal to 5 degrees radius.

the argus ii system is intended for use in blind patients with severe to profound retinitis pigmentosa with at least some light perception in the eye to be implanted. the majority of rp patients still have some central vision even at a very late stage of the disease. this extremely restricted visual field is, however, highly disabling in daily life. the primary objective of this study is to evaluate the safety and benefit of the argus ii system in rp patients characterized as late stage with a central residual visual field smaller than or equal to 5 degrees radius . the electrode array will be placed in a para- to peri foveal location adjacent to the subject's residual visual field, thus increasing the total retinal area receptive to light. safety data will be monitored to ensure continued acceptability of risks to study subjects and visual function will be measured to evaluate the effectiveness of the system in this "better vision" rp population. in addition, effects on functional vision and quality of life will be assessed through the functional low-vision observer rated assessment (flora) and the national eye institute visual function questionnaire (nei-vfq-25).

Eligibility criteria:
inclusion criteria: * adults, age 25 years or older; * diagnosed with advanced retinitis pigmentosa (including syndromic rp), choroideremia, leber's congenital amaurosis, or rod-cone disease; * a measurable central residual visual field of 5° radius or smaller in both eyes, as determined by goldmann perimetry; * visual acuity of 0.1 (1.0 logmar) or worse in the eye to be implanted, as measured by etdrs chart; * previous history of useful form vision; * provided written, informed consent to participate in the study. exclusion criteria: * ocular diseases or conditions that could prevent the argus ii implant from working (e.g., optic nerve disease, central retinal artery or vein occlusion, history of retinal detachment, trauma, etc.); * ocular structures or conditions that could prevent the successful implantation of the argus ii implant or adequate healing from surgery (e.g. extremely thin conjunctiva; axial length \ 26 mm; corneal ulcers; choroidal neovascularization in the area of the intended tack location, etc.); * pre-disposition to eye rubbing; * any disease or condition that prevents understanding or communication of informed consent, study demands, and testing protocols, including: 1. cognitive decline including diagnosed forms of dementia and/or progressive neurologic disease, 2. psychiatric disease including diagnosed forms of depression; 3. does not speak a principal language associated with the region, and 4. deafness or selective frequency hearing loss that prevents hearing device alarms and alerts; * pregnant or wish to become pregnant during the course of the study; * participating in another investigational drug or device study that may conflict with the objectives, follow-up, or testing of this study; * inability to tolerate general anaesthesia or the recommended antibiotic and steroid regimen associated with the implantation surgery; * conditions likely to limit life to less than 1 year from the time of inclusion.