Intact cone inner segment mosaics underlying non-waveguiding cones have also been described in other inherited retinal diseases, such as achromatopsia [e.g. (16, 32, 33)], RDH5-associated fundus albipunctatus (34), oligocone trichromacy (35), retinitis pigmentosa and Usher syndrome (36). The gene discussed is RDH5; the disease is retinitis pigmentosa.