3 Intro To Vision Flashcards
Accommodation (focus)
In vision, bringing objects located at different distances into focus by changing the shape of the lens.
Absorption spectrum
Plot of the amount of light absorbed by a visual pigment versus the wavelength of light.
Amacrine cells
Neuron that transmits signals laterally in the retina. Amacrime cells synapse with bipolar cells and ganglion cells.
Axial myopia
Myopia (nearsightedness) in which the eyeball is too long.
Belongingness
Hypothesis that an area’s appearance is influenced by the part of the surroundings that the area appears to belong to. This principle has been used to explain the perception of whiteness in the Benary cross and White’s Illusion.
Bipolar cells
Retinal neurons that receives input from the visual receptors and send signals to the retinal ganglion cells.
Blind spot
Small area where the optic nerve leaves the back of the eye. There are no visual receptors in this area, so small images falling directly on the blind spot cannot be seen.
Cone
Cone-shaped receptors in the retina that are primarily responsible for vision in high levels of illumination and for color vision and detailed vision.
Cornea
Transparent focusing element of the eye that is the first structure through which light passes as it enters the eye. The cornea is that I possibly have some major focusing element.
Dark adaption
Visual adaption that occurs in the dark, during which the sensitivity to light increases. This increase in sensitivity is associated with regeneration of the rod and cone visual pigments.
Dark adoption curve
Function that traces the time course of the increasing visual sensitivity that occurs during dark adaptation.
Dark-adapted sensitivity
Sensitivity of the eye after it has completely adapted to the dark.
Detached retina
Condition in which the retina detached from the back of the eye.
Electromagnetic spectrum
Continuum of electromagnetic energy that extends from very-short-wavelength gamma rays to long-wavelength radio waves. Visible light is a new band within the spectrum.
Enzyme cascade
Sequence of reactions triggered by an activated visual pigment molecule that results in transduction.
Eye
Eyeball and its contents, which include focusing elements, the retina, and supporting structures.
Far point
Distance at which the spot of light becomes focused on the retina.
Farsightedness
Hyperopia
Fovea
Small area in the human retina contains only cone receptors. The fovea is located on the line of sight, so that when a person looks at an object, the center of its image falls on the fovea.
Ganglion cells
Neuron in the retina receives inputs from bipolar and amacrine cells. The axons of the ganglion cells travel out of the eye in the optic nerve.
Hermann grade
Geometrical display that results in the illusion of dark areas at the intersection of two white “corridors.” This perception can be explained by lateral inhibition.
Horizontal cells
Neurons that transmits signals laterally across the retina. Horizontal cells synapse with receptors and bipolar cells.
Hyperopia
Condition causing poor vision he which people can see objects that are far away but do not see near objects clearly. Farsightedness.
Isomerization
Changing shape of the retinal part of the visual pigment molecule that occurs when the molecule absorbs a quantum of light. Isomerization triggers the enzyme cascade that result in transduction from light energy to electrical energy into retinal receptors.
Laser-assisted in situ keratomileusis
Process in which the cornea is sculpted with the laser in order to achieve clear vision by adjusting the focusing power of the cornea so it focuses light onto the retina.