Plays a critical role in eye formation by regulating the initial specification of retinal cells and/or their subsequent proliferation. Highly expressed in anterior neural plate followed by neural retina, pigmented epithelium, in pineal gland, diencephalon floor and epiphysis. At later stages, the neuroretina remains the primary site of expression. No expression in the developing lens and cornea. Expression begins in stage 11 (late-gastrula) embryos and then appears to be maintained at fairly stable levels up to stage 45 (late tadpole), when it declines. Belongs to the paired homeobox family. Bicoid subfamily. It is uncertain whether Met-1 or Met-9 is the initiator.