25 terms

HBS visual perception ACT. 2.4.2

STUDY
PLAY
Photoreceptors
There are two special types. Located in the retina.
Rods
Function in dim light and perceive shades of gray.
Cones
Function in bright light and provide sharp, colorful images.
The three types of cones?
-red cones
-blue cones
-green cones
Color deficiency? Occurs when?
(Color blindness)
Any of the cones malfunction.
Depth perception
Ability to judge the relative distances between objects in three dimensions.
With one eye?
(Depth perception)
the field appears two-dimensional.
Accommodation?
Is the combo of reflex actions by which the lens of the eye changes to keep focal length, the distance between the center of the lens and its focal point, constant.
Ciliary
In the eye assist adjustment of the lens.
What two parts of the eye focus on light?
Cornea and lens
Cornea
It can not change shape, but does most of the work.
Lens
Carries out fine adjustments.
Astigmatism
Is a condition in which the cornea or the lens is irregularly shaped.
What happens when the shape of the eye changes?
The incoming light rays to refract and converge improperly.
What is the vision like for a person with astigmatism?
The light cant focus on a certain point on the retina so it causes a blurry or distorted image.
How to correct astigmatism?
Eyeglasses, contact lenses, or refractive surgery.
Blind spot
Where the optic nerve exists the eye at the retina on its way to the brain.
Why is it a blind spot?
This area doesn't have any receptors that respond to light. So the image that falls in this area can not be seen.
Peripheral vision
The ability to see things that fall outside of the direct line of vision.
What is responsible for your peripheral vision?
Due to the proximity to the edge of the retina, your rods are responsible.
What is your peripheral vision used for?
It is better for detecting movement then shape images, it is also stronger in the dark.
Optical illusions
Are visual tricks that actually take place in the brain rather then the eye.
Visual cortex
Deciphers images sent form the eye, however surrounding objects, intense colors, distortion a of expected patterns, and preconceptions can cause the mind to "see" and internet an image differently.
Afterimages
Are optical illusions that occur when looking away after staring intently at a fixed image or color.(fatigue your cones)
Why do the cones get fatigued?
The constant light stimulating the retina is what causes this.
YOU MIGHT ALSO LIKE...