Involved in ventral eye development. At early neurula stages, exclusively activated in the presumptive ventral telencephalon. Since midneurula stages also found in the medial aspect of the eye field. At tailbud and tadpole stages, expression seen in the optic stalk, optic nerve, optic disk, ventral retina, ventral telencephalon and diencephalon. Finally during metamorphosis expression is maintained in the optic chiasm, ventral hypothalamus and hypophysis. Belongs to the EMX homeobox family.