CPK850 is a recombinant adeno-associated virus 8 (AAV8) vector containing the human RLBP1 gene. The purpose of this first-in-human study is to explore the maximum tolerated dose (MTD) of CPK850 as determined by the single ascending dose ranging portion of the study. This study will also evaluate the safety and potential efficacy of CPK850 on improving visual function in patients with decreased visual function from RLBP1 retinitis pigmentosa due to biallelic mutations in the RLBP1 gene.