Retina

The retina is the inner layer of the eyeball, located between the choroidea and the membrane of the vitreous body. It is an extension of the brain, with which it is connected by the optic nerve. It contains the photoreceptor cells and neurons that transform light into a nervous message.

The retina is composed of two parts:

• The nonvisual retina, covering the ciliary body and the posterior surface of the iris.

• The optic part of retina, covering the inner surface of the choroidea.

These two parts are separated by the ora serrata, located at the base of the ciliary body.

The retina is composed of superposed layers. Primarily a pigment layer and a neural layer, which is itself divided into several layers.

On the surface of the retina, we can distinguish the retinal blood vessels that delimit the macula, where visual acuity is the greatest. We can also distinguish the disc of optic nerve, where the axons of retinal neurons form the optic nerve and cross the sclera. Through the retina, we can also perceive the tapetum lucidum, which reflects light so that photoreceptor cells can absorb more light.