Engineering

Artificial eye comes closer to human eye capabilities

A team of researchers at The Hong Kong University of Science and Technology, the University of California, Berkeley and Lawrence Berkeley National Laboratory has built an artificial eye with capabilities that come close to ...

Engineering

Glowing contact lens could prevent a leading cause of blindness

Hundreds of millions of people suffer from diabetes worldwide, putting them at risk for a creeping blindness, or diabetic retinopathy, that comes with the disease in its more advanced stages. Existing treatments, though effective, ...

Hi Tech & Innovation

Google patent filing proposes device in eye to address poor vision

(Tech Xplore)—What are Google's visionaries up to these days? You may be sorry you asked. Discovery reported that an electronic device injected into an eyeball is the focus of a patent filed by Google. The application ...

Retina

The vertebrate retina is a light sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses. These are sent to various visual centers of the brain through the fibers of the optic nerve.

In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, so the retina is considered part of the central nervous system (CNS).. It is the only part of the CNS that can be imaged non-invasively in the living organism.

The retina is a complex, layered structure with several layers of neurons interconnected by synapses. The only neurons that are directly sensitive to light are the photoreceptor cells. These are mainly of two types: the rods and cones. Rods function mainly in dim light and provide black-and-white vision, while cones support daytime vision and the perception of colour. A third, much rarer type of photoreceptor, the photosensitive ganglion cell, is important for reflexive responses to bright daylight.

Neural signals from the rods and cones undergo complex processing by other neurons of the retina. The output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve. Several important features of visual perception can be traced to the retinal encoding and processing of light.

This text uses material from Wikipedia, licensed under CC BY-SA