Numa et al. suggested that tier-based approach is more efficient to detect pathogenic variants in Japanese RP as following orders: (1) Sanger sequencing of two major mutations in EYS, (2) targeted sequencing of all EYS coding exons, (3) WGS, and (4) Sanger sequencing of the Alu element in RP124. This evidence concerns the gene EYS and retinitis pigmentosa 1.