The optic part of the retina consists of two layers, an outer pigmented layer and an inner neural layer:
The pigmented layer is firmly attached to the choroid and continues anteriorly over the internal surface of the ciliary body and iris.
The neural layer, which can be further subdivided into its various neural components, is only attached to the pigmented layer around the optic nerve and at the ora serrata.
It is the neural layer that separates in the case of a detached retina.