Zonula occludens 1 (ZO-1) is one of the most abundant proteins of the RPE tight junctions, and its distribution becomes discontinuous and strongly irregular when the oBRB is altered, as is the case of RP or other ocular diseases with a major inflammatory component (Rizzolo, 2007; Naylor et al., 2019; Napoli et al., 2021); these alterations can be prevented by treatments repairing the outer retina. This evidence concerns the gene TJP1 and retinitis pigmentosa 1.