| Human Eye Development
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| Stage
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Event
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| Stage 10
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optic primordia appear.
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| Stage 11
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right and left optic primordia meet at the optic chiasma forming a U-shaped rim.
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| Stage 12
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optic neural crest reaches its maximum extent and the optic vesicle becomes covered by a complete sheath,
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| Stage 13
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By the end of the fourth week the optic vesicle lies close to the surface ectoderm. Optic evagination differentiation allows identification of optic part of retina, future pigmented layer of retina, and optic stalk. The surface ectoderm overlying the optic vesicle, in response to this contact, has thickened to form the lense placode.
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| Stage 14
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(about 32 days) the lens placode is indented by the lens pit, cup-shaped and still communicates with the surface by a narrowing pore.
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| Stage 15
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(about 33 days) the lens pit is closed. The lens vesicle and optic cup lie close to the surface ectoderm and appear to press against the surface.
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| Stage 16
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(37 days) Growth of the lens body results in a D-shaped lens cavity. Perilental blood vessels (tunica vasculosa lentis) are visible. Prior to the development of the eyelids, one small sulcus or groove forms above the eye (eyelid groove) and another below it.
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| Stages 17 - 19
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Retinal pigment is visible and the retinal fissure is largely closed. Eyelids grooves deepen, eyelid folds develop, first below, and then above, the eye.
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| Stages 18
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Mesenchyme invades the region between the lens epithelium and the surface ectoderm.
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| Stages 19 - 22
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the eyelid folds develop into the eyelids and cover more of the eye as the palpebral fissure takes shape. The upper and the lower eyelids meet at the outer canthus in Stage 19.
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| Stage 20
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The lens cavity is lost and a lens suture begins to form. The inner canthus is established.
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| Stage 23
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The retina comprises the pigmented layer, external limiting membrane, proliferative zone, external neuroblastic layer, transient fiber layer, internal neuroblastic layer, nerve fiber layer, and internal limiting membrane. Eyelids closure is complete (Note - shown as still open in the Kyoto embryo).
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Data from a study of human embryonic carnegie stages[1] and other sources.
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