These deposits gradually grow in size and number, leading to increasingly distorted vision.ģ. The cause is unclear, but by-products from photoreceptors are thought to contribute.Ģ. AMD is caused by a build-up of fatty deposits, known as drusen, between the RPE and the choroid. The most common such condition is age-related macular degeneration (AMD).ġ.
A common failingĭegenerative diseases of the retina affect hundreds of millions of people worldwide. It forms a barrier to blood vessels in the choroid and mops up harmful substances that are shed by photoreceptors in response to light. Retinal pigment epithelium (RPE) A layer of epithelial cells that lies beneath the photoreceptors. So far, around 30 subtypes have been identified.Ħ.
Amacrine cell Reaches across several bipolar cells to regulate signals directed at retinal ganglion cells. Horizontal cell Regulates the signal that emerges from several rods and cones.ĥ. Retinal ganglion cell Relays signals from bipolar and amacrine cells to the brain through long projections called axons that form the optic nerve.Ĥ. Bipolar cell Responsible for transmitting signals from photoreceptors to a retinal ganglion cell.ģ. Photoreceptors convert light into electrical signals that travel through other retinal neurons to reach the optic nerve.Ģ. Rods enable vision in poor light, whereas cones are responsible for colour vision. Photoreceptors There are two main types of light-sensitive cell in the eye: rods and cones. When light hits the retina, it stimulates photoreceptors, creating an electrical signal that is conveyed through other neurons of the retina to the optic nerve, and then on to the brain.ġ. In the retina, five types of neuron - photoreceptors, bipolar cells, retinal ganglion cells, horizontal cells and amacrine cells - are wired together to form one of nature’s most complex circuit boards. This intricate structure is essential for vision. The retina comprises a thin layer of light-sensitive tissue at the back of the eye.
#RETINA FUNCTION EYE PDF#
Download a PDF of the graphic Weird wiring
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