Two laminar structures line the back of the eye: the retinal pigment epithelium (RPE) and the neural retina. This chapter discusses the neurosensory retina; the RPE is discussed in Chapter 13. These laminar structures arise from an invagination of the embryonic optic cup that folds the neuroectodermal layer into apex-to-apex contact with itself, creating the subretinal space (Fig 12-1). The 2 layers form a hemispheric shell on which the visual image is focused by the anterior segment of the eye. The retina is composed of neural, glial, and vascular components.
The neural retina contains multiple types of cells (see also Chapter 2):
photoreceptors (rods and 3 types of cones)
bipolar cells (rod on-bipolar cells and cone on- and off-bipolar cells)
interneurons (horizontal and amacrine cells)
ganglion cells and their axons, which form the retinal nerve fiber layer and the optic nerve
glial cells, including astrocytes, Müller cells, and microglia
Figure 12-1 Development of the retina and the retinal pigment epithelium. A, Apposition of the surface ectoderm (E) with the inner wall of the optic cup (arrowheads); the neural retina (NR) is separated from the outer wall and the pigment epithelium (PE) by the subretinal space (*).B, Further invagination of the optic cup with induction of the overlying lens (L) by the NR. The intervening subretinal space separates the NR from the PE.
(Modified with permission from Ryan SJ, Ogden TE, Hinton DR, Schachat AP, Wilkinson CP.
3rd ed. St Louis: Mosby; 2001:5.)
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.