This is part of the central nervous system.
It is made up of a million receptors per eye and their connections which lead into the optic nerve.
It can be divided into two areas the central retina (macula) and the peripheral retina. The peripheral retina is useful for detecting movement and objects in the outer part of vision. It also helps to fuse the picture from each eye. It enables us to see in the dark as it has a large number of rod receptors.
If a break develops in the retina fluid vitreous can leak under the retina and cause a retinal detachment.
The retinal pigment layer lies outside the retina but inside the choroid. The pigment cells act as a nurse to the retinal receptors, they meet their every need. If the pigment layer is sick then the retina begins to fail.
The choroid is a layer of blood vessels which provide nutrients and removes waste products from the pigment layer, which does the same for the retina. The choroid has the highest rate of blood flow per gram of tissue in the body.
Circulatory problems and uveitis and rarely tumours can effect the choroid.
This information site has been provided by varied UK and US eye doctors for patients with eye problems.
Once your eye doctor has made a diagnosis or recommended an investigation or treatment, then you will be able to find further explanation on this site.
It is not a self diagnosis centre. It should not be relied upon without taking professional advice.