The cornea develops from the ectoderm overlying the lens. Corneal epithelial layers proliferate and generate multiple layers. the corneas main function is to refract or bend light. It also acts as a protective outer layer to the eye.

Upon neural retina specification, signals from the neural retina induce lens fate in the overlying surface ectoderm. The lens placode then invaginates to give rise to the lens vesicle, which buds out at around 24hpf. The lens vesicle keeps growing throughout adulthood and fibre cells differentiation is maintained from a pool of undifferentiated proliferating epithelial cells located at the most anterior region of the vesicle.

Upon neural retina specification, signals from the neural retina induce lens fate in the overlying surface ectoderm. The lens placode then invaginates to give rise to the lens vesicle, which buds out at around 24hpf. The lens vesicle keeps growing throughout adulthood and fibre cells differentiation is maintained from a pool of undifferentiated proliferating epithelial cells located at the most anterior region of the vesicle.

In the zebrafish eye, all the stages of progression from stem cell to differentiated neuron are found near the margin of the eye in a region termed the ciliary marginal zone (CMZ).  This type of retinal stem cell niche is found in all non-mammalian vertebrates and contain perpetually self-renewing, proliferative neuroepithelial cells that are spatially ordered with respect to cellular development and differentiation.  The youngest and least determined cells are most peripheral, proliferative retinoblasts are located in the middle, and the quiescent, differentiating cells are most central

Ganglion cells are the final output neurons of the vertebrate retina. They project axons to various retino-recipient brain nuclei on route to the optic tectum.

Ganglion cells are the final output neurons of the vertebrate retina. They project axons to various retino-recipient brain nuclei on route to the optic tectum.

Within the inner plexiform layer are localized synapses between the amacrine and bipolar interneurons and the retinal ganglion cells. Connections between cells that are depolarized upon an increase in illumination (ON) occupy approximately the inner half of the IPL, whereas synapses of cells hyperpolarized (OFF) by light are confined to the outer half of the IPL.

Within the inner plexiform layer are localized synapses between the amacrine and bipolar interneurons and the retinal ganglion cells. Connections between cells that are depolarized upon an increase in illumination (ON) occupy approximately the inner half of the IPL, whereas synapses of cells hyperpolarized (OFF) by light are confined to the outer half of the IPL.

Layer of the nerual retina that contains the interneurons, the horizontal, bipolar and amacrine cells.

Layer of the nerual retina that contains the interneurons, the horizontal, bipolar and amacrine cells.

In the outer plexiform layer, photoreceptors form chemical synapses with horizontal cells and bipolar cells.

Photoreceptor cells span the outer nuclear layer. Located in the apical-most layer of the retina, photoreceptors display a stereotypical subcellular organization with their nuclei basal to the inner segment (cell body or soma) and outer segment, which abuts the retinal pigmented epithelium (RPE) and is full of membrane invaginations packed with light-sensitive cell-specific opsins.  All photoreceptors have opsin-containing outersegments, which are replaced on a daily basis.

Photoreceptor cells span the outer nuclear layer. Located in the apical-most layer of the retina, photoreceptors display a stereotypical subcellular organization with their nuclei basal to the inner segment (cell body or soma) and outer segment, which abuts the retinal pigmented epithelium (RPE) and is full of membrane invaginations packed with light-sensitive cell-specific opsins. All photoreceptors have opsin-containing outersegments, which are replaced on a daily basis.

3dpf transverse section.

Nissl(green) and anti-tubulin(red).

The retinal pigmented epithelium (RPE), like the neural retina, is derived from the neural ectoderm.This tissue is required for the function and survival of photoreceptor cells. The RPE is a typical epithelial monolayer of tightly packed cuboidal cells forming part of the blood brain barrier between the vascular choroid and the neural retina. The cells contain large numbers of melanosomes packed with melanin granules. The apical microvilli of the RPE interdigitate with the photoreceptor outer segments, and the basal surface rests on Bruch’s membrane, the basement membrane between the RPE and capillaries of the choroid.

Cranial nerve II

Transmits visual information from the neural retina to the optic tectum and other retino-recipient brain nuclei. It is formed of retinal ganglion cell axons.

Cranial nerve II

Transmits visual information from the neural retina to the optic tectum and other retino-recipient brain nuclei. It is formed of retinal ganglion cell axons.

The point at which the optic nerves decussate or cross the midline on their way to innervate the optic tectum and other AFs .

the continuation of the optic nerve once it has decussated at the optic chiasm.