BackgroundA position paper based on the collective experiences of Argus II Retinal Prosthesis System investigators to review strategies to optimize outcomes in patients with retinitis pigmentosa undergoing retinal prosthesis implantation.MethodsRetinal surgeons, device programmers, and rehabilitation specialists from Europe, Canada, Middle East, and the United States were convened to the first international Argus II Investigator Meeting held in Ann Arbor, MI in March 2015. The recommendations from the collective experiences were collected. Factors associated with successful outcomes were determined.ResultsFactors leading to successful outcomes begin with appropriate patient selection, expectation counseling, and preoperative retinal assessment. Challenges to surgical implantation include presence of staphyloma and inadequate Tenon’s capsule or conjunctiva. Modified surgical technique may reduce risks of complications such as hypotony and conjunctival erosion. Rehabilitation efforts and correlation with validated outcome measures following implantation are critical.ConclusionsBringing together Argus II investigators allowed the identification of strategies to optimize patient outcomes. Establishing an on-line collaborative network will foster coordinated research efforts to advance outcome assessment and rehabilitation strategies.

Early-onset severe retinal degeneration (EOSRD) is a genetically heterogeneous group of diseases resulting in serious visual disability in children. A significant number of EOSRD cases, often diagnosed as Leber congenital amaurosis (LCA13), are associated with mutations in the gene encoding retinol dehydrogenase 12 (RDH12). RDH12 is a member of the enzyme family of short-chain dehydrogenases/reductases. In the retina, RDH12 plays a critical role in reducing toxic retinaldehydes generated by visual cycle activity that is required for the light response of the photoreceptor cells. Individuals with RDH12 deficiency exhibit widespread retinal degeneration impacting both rods and cones. Although Rdh12-deficient (Rdh12-/-) mice do not exhibit retinal degeneration, functional deficits relevant to visual cycle function can be demonstrated. In the present study we describe the development and pre-clinical testing of a recombinant adeno-associated viral (rAAV) vector that has potential for use in treating EOSRD due to RDH12 mutations. Wildtype and Rdh12-/mice that received a sub-retinal injection of rAAV2/5 carrying a human RDH12 cDNA driven by a human rhodopsin-kinase promoter exhibited transgene expression that was stable, correctly localized, and did not cause retinal toxicity. In addition, administration of the vector reconstituted retinal reductase activity in the retinas of Rdh12-/mice, and decreased susceptibility to light damage associated with Rdh12 deficiency, thus demonstrating potential therapeutic efficacy in an animal model that does not exhibit a retinal degeneration phenotype. These findings support further efforts to develop gene-replacement therapy for individuals with RDH12 mutations.

ison of fundus-guided microperimetry and multifocal electroretinography for evaluating hydroxychloroquine maculopathy.