Transcription factor that controls lens epithelial cell growth through regulation of proliferation, apoptosis and cell cycle (PubMed:10652278, PubMed:10890982). During lens development, controls the ratio of the lens fiber cells to the cells of the anterior lens epithelium by regulating the rate of proliferation and differentiation (PubMed:16199865). Controls lens vesicle closure and subsequent separation of the lens vesicle from ectoderm (PubMed:10652278). Is required for morphogenesis and differentiation of the anterior segment of the eye (PubMed:17064680). Controls the expression of DNAJB1 in a pathway that is crucial for the development of the anterior segment of the eye (By similarity). Expressed in the embryonic lens. Expressed in the developing lens from the start of lens placode induction and becomes restricted to the anterior proliferating cells when lens fiber differentiation begins. Head ectoderm expression is induced by RAX and lens expression is induced by PAX6. Defects in Foxe3 are the cause of the dysgenetic lens (dyl) phenotype. In mouse mutant dyl the lens vesicle fails to separate from the ectoderm, causing a fusion between the lens and the cornea. Lack of a proliferating anterior lens epithelium leads to absence of secondary lens fibers and a dysplastic, cataractous lens. Knockout mice are viable and fertile but show eye abnormalities; in some cases the eyes never open. Eyes are much smaller, the anterior chamber is not formed, and the pupil is markedly smaller. There are no abnormalities in brain development (PubMed:16199865). Mice show reduced smooth muscle cell (SMC) density and impaired SMC differentiation that is limited to the ascending aorta (PubMed:26854927).