Difference between revisions of Eyeballs
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→Parts of the eye: update rod/cone stuff
(→Parts of the eye: add macula and fovea) |
(→Parts of the eye: update rod/cone stuff) |
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* '''Lens''' - The part that changes the focus distance of the eye | * '''Lens''' - The part that changes the focus distance of the eye | ||
* '''Rods and cones''' - Rods and Cones are the sensory cells in the back of your eye that detect light. | * '''Rods and cones''' - Rods and Cones are the sensory cells in the back of your eye that detect light. | ||
** Rods sense only light intensity, not color. | ** Rods sense only light intensity, not color. They require lower levels of light to trigger, and so work better in low-light conditions. They are more sensitive to movement, and tend to be concentrated on the periphery of the retina. If you are outside at dusk, you may feel a sudden switch of your vision from color vision to black and white, this is your [[visual cortex]] switching to only rod input when cone input isn't working as well in dim light. | ||
** Cones are the cells that detect color in your eye. There are three different types of cones that respond most strongly to three different wavelengths of light. Your visual cortex takes the combined response of the three types of cones and makes up the blended color in your mind. Magenta for example is an imaginary color. It's the color your brain makes up to explain why both short and long wavelengths of light are detected, but not the wavelengths in the middle. Most colors are on the color spectrum you learned in school (Red, Orange, Yellow, Green, Blue, Indigo, Violet), and will trigger a single cone type, or two adjacent cone types. | ** Cones are the cells that detect color in your eye, but require much higher light levels to trigger. They concentrated in the macula, where high-resolution acuity is required. There are three different types of cones that respond most strongly to three different wavelengths of light, though there is a large overlap. Your visual cortex takes the combined response of the three types of cones and makes up the blended color in your mind. Magenta for example is an imaginary color. It's the color your brain makes up to explain why both short and long wavelengths of light are detected, but not the wavelengths in the middle. Most colors are on the color spectrum you learned in school (Red, Orange, Yellow, Green, Blue, Indigo, Violet), and will trigger a single cone type, or two adjacent cone types. | ||
* '''Retina''' - the tissue that supports the rods and cones. | * '''Retina''' - the tissue that supports the rods and cones. | ||