Binds to the 37-bp core of the locus control region (LCR) of the red/green visual pigment gene cluster (PubMed:10903837). May regulate the activity of the LCR and the cone opsin genes at earlier stages of development (PubMed:10903837). Dispensable in early retinal development (By similarity). Additional isoforms seem to exist. In the adult eye, expressed in lens, iris, ciliary body, choroid, optical nerve head and, most strongly, in retina, but not expressed in sclera and cornea. According to PubMed:11978762, expressed in adult retina but not in lens and cornea. Within adult retina, found exclusively in the inner nuclear layer. Isoform 1, isoform 2, isoform 3 and isoform 4 expressed in adult retina, but not in brain, heart, kidney, liver, lung, pancreas, placenta and skeletal muscle. Not expressed in thymus and spleen. Expressed in embryonic craniofacial tissue. Expressed in fetal (week 14) retina. Strongly expressed in neonatal retina, weakly in neonatal lens, choroid and cornea (day 1, 4; month 9). The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Major form. Major form. Minor form. Minor form. Belongs to the paired homeobox family.