optic cup n.
A two-walled cuplike depression, formed by invagination of the optic vesicle, that develops into the pigmented and sensory layers of the retina. Also called eyecup.
They are merely dependent on slight differences in the manner in which the mesoblast enters the optic cup.
Wherever the optic cup of the embryo is transplanted under the epithelium the latter will be transformed into a transparent lens.
It consists of a core of mesoblast covered by a delicate layer derived from both strata of the optic cup.
At first the two walls of the optic cup do not greatly differ in thickness.
The optic cup is at first very shallow, but owing to the rapid growth of the free edge of its walls soon becomes fairly deep.
There are however two parts of this seam where the edges of the optic cup have not coalesced.
The walls of the edge of the optic cup become very much thinner than those of the true retinal part.
The optic cup, or its contained fluid, is one chemical compound; epithelium is another; mesoblast is a third.
The lens is carried outwards with the growth of the optic cup, leaving the cavity of the cup quite empty.
This process of tissue is very easily seen, and swells out on entering the optic cup into a mushroom-like expansion.