HBS

retina

layer of light sensitive cells at back of eye, detects images

iris

muscle that controls how much light enters the eye

vitreous humor

thick/clear jelly that help give the eye shape

cornea

tough/clear covering over the iris and pupil that helps protect the eye

pupil

dark circle in the center of the iris lets light into the inner eye

sclera

thick, tough, white outer covering of the eye

lens

clear, flexible structure that makes an image on they eye's retina; focuses on objects that are close up and objects that are far away

aqueous humor

clear fluid that helps the cornea keep its round shape

tapetum

colorful/shiny material behind the retina reflects light back through the retina

optic nerve

the bundle of nerve fibers that carry info from the retina to the brain

blind spot

place where optic nerve leaves the retina

what are the two types of nerve cells in color vision?

rod and cones

rods

function in dim light and sees shades of gray

cones

bright light and show bright/colorful images

what are the 3 types of cones?

green, blue, and red

depth perception

ability to judge relative distances between objects in three dimensions

accommodation

combo of reflex actions by which the lens of eyes changes to keep focal length, distance between center of lens and focal point, constant

astigmatism

condition where the cornea/lens is irregularly shaped; light is refracted and converged improperly; blurry distorted image

optical illusions

visual tricks taken place in the brain rather than the eye; visual cortex of the brain deciphers images, but can be changed by the mind to see and interpret image

peripheral vision

ability to see things that fall out of the direct line of vision; rods are responsible; better fort detecting movement, stronger in the dark

after images

optical illusions that occur looking away after staring at an image or color; cones become fatigued, lasts briefly