Related topics: brain · nerve cells · current biology · retina

Laser-based technology helps doctors image full eye in 3-D

It is estimated that in 2015, 217 million people had moderate to severe vision impairment, while 36 million were blind, according to an article in the journal The Lancet Global Health. The World Health Organization predicts ...

The space rock that hit the moon at 61,000 kilometers an hour

Observers watching January's total eclipse of the Moon saw a rare event, a short-lived flash as a meteorite hit the lunar surface. Spanish astronomers now think the space rock collided with the Moon at 61,000 kilometres an ...

New bird species discovered

In the lush, lowland rainforests on the island of Borneo lives a rather common, drab brown bird called the Cream-vented Bulbul, or Pycnonotus simplex. This bird is found from southern Thailand to Sumatra, Java and Borneo. ...

3-D models reveal why bigger bumblebees see better

By generating 3-D images of bumblebees' compound eyes, researchers at Lund University in Sweden have discovered how bumblebees differ in their vision. The results could contribute to increased knowledge about the pollination ...

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Eye

Eyes are organs that detect light, and send signals along the optic nerve to the visual and other areas of the brain[citation needed]. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in cnidaria, molluscs, chordates, annelids and arthropods.

The simplest "eyes", such as those in unicellular organisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.

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