During embryonic development of the eye, the outer wall of the bulb of the optic vesicles becomes thickened and invaginated, and the bulb is thus converted into a<unk> , the<unk> (or ophthalmic<unk> , consisting of two strata of cells. These two strata are continuous with each other at the<unk>  margin, which ultimately overlaps the front of the lens and reaches as far forward as the future aperture of the pupil. The<unk> is part of the diencephalon and gives rise to the retina of the eye.
Optic cup 
Optic pit
Corneal button
Scleral lens
Supplementary eye field
Optic vesicle
Optic recess
Stenopaeic slit