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level: Visual Perception

Questions and Answers List

level questions: Visual Perception

Question	Answer
To take up something - such as light, noise or energy - and not transmit it at all	Absorb
The process by which the eye changes its focus (in which the lens gets fatter as gaze is directed toward nearer objects)	Accommodation
A disease associated with aging that affects the macula. It gradually destroys sharp central vision, making it difficult to read, drive and recognise faces. There are forms: Wet and Dry	Age-related macular degeneration (AMD)
A retinal cell found in the inner synaptic layer that makes synaptic contacts with bipolar cells, ganglion cells and other amacrine cells	Amacrine cell
The watery fluid in the anterior chamber of the eye	Aqueous Humour
A visual defect caused by the unequal curving of one or more of the refractive surfaces of the eye, usually the cornea	Astigmatism
A retinal cell that synapses with either rods or cones (not both) and with horizontal cells, and then passes the signals on to ganglion cells	Bipolar cell
An opacity of the crystalline lens	Cataract
The light-catching part of the visual pigments of the retina	Chromophore
A photoreceptor specialised for daylight vision, fine visual acuity and colour	Cone
The difference in luminance between an object and the background, or between lighter and darker parts of the same object	Contrast
The transparent 'window' into the eyeball	Cornea
A Bipolar retinal cell whose processes are spread out to receive input from multiple cones	Diffuse bipolar cell
A unit of measurement of the optic power of a lens. It is equal to the reciprocal of the focal length, in meters. A 2-ddiopter lens will bring parallel rays of light into focus at 0.5 meter (50cm)	Diopter (D)
In reference to the retina, consisting of two parts: the rods and cones, which operate under different conditions	Duplex
The distance between the retinal image and the fovea	Eccentricity
The condition in which there is no refractive error, because the refractive power of the eye is perfectly matched to the length of the eyeball	Emmetropia
An acoustic, electricl, electronic or optical device, instrument, computer program, or neuron that allows the passage of some range of parameters and blocks the passage of others	Filter
The distance between the lens (or mirror) and the viewed object, in meters	Focal distance
A small pit located near the center of the macula and containing the highest concentation of cones, and no rods. It is the portion of the retina that produces the highest visual acuity and serves as the point of fixation	Fovea
The back layer of the retina: what the eye doctor sees through an ophthalmoscope	Fundus
A retinal cell that receives visual information from photoreceptors via wo intermediate neuron types (bipolar cells and amacrine cells) and transmits information to the brain and midbrain	Ganglion cell
An electrical potential that can vary continuously in amplitude	Graded potential
A specialised retinal cell that contacts both photoreceptor and bipolar cells	Horizontal cell
The perceptual attribute of colours that enables them to be classed as similar to red, green, blue or something inbetween	Hue
Farsightednes, a common condition in which light entering the eye is focused behind the retina and accommodation is required in order to see near objects clearly	Hyperopia
A change in membrane potential such that the inner membrane surface becomes more negative than the outer membrane surface	Hyperpolarisation
A picture or likeness	Image
the part of a photoreceptor that lies between the outer segment and the cell nucleus	Inner segment
The coloured part of the eye, consisting of a muscular diaphragm surrounding the pupile and regulating the light entering the eye by expanding and contracting the pupil	Iris
A neuron located between the magnocellular and parvocellular layers of the lateral geniculate nucleus.	Koniocellular cell
Antagonistic neural interaction between adjacent regions of the retina	Lateral inhibition
The lens inside the eye that enables the changing of focus	Lens
A ganglion cell resembling a little umbrella that receives excitatory input from diffuse bipolar cells and feeds the magnocellular layer of the lateral geniculate nucleus	M ganglion cell
A photopigment, found in a class of photoreceptive retinal ganglion cells, that is sensitive to ambient light	Melanopsin
A small bipolar cell in the central retina that receives input from a single cone	Midget bipolar cell
Nearsightedness, a common condition in which light entering the eye is focused in front of the retina and distant objects cannot be seen sharply	Myopia
A bipolar cell that hyperpolarises in response to an increase in light captured by the cones	OFF Bipolar cell
A cell that increases firing in response to a decrease in light intensity in its receptive-field center	OFF Center cell
A bipolar cell that depolarises in response to an increase in light captured by the cones	ON Bipolar cell
A cell that increases firing in response to an increase in light intensity in its receptive-field center	ON Center cell
An oscillation that travels through a medium by transferring energy from one particle or point to another without causing an permanent displacement of the medium	Wave
The transparent fluid that fills the vitreous chamber in the posterior part of the eye	Vitreous humor
The angle that an object subtends at the eye	Visual angle
The location where acons terminate at the synapse for transmission of information by the release of a chemical transmitter	Synaptic terminal
A photoreceptor specialised for night vision	Rod
The visual pigment found in rods	Rhodopsin
A progressive degeneration of the retina that affects night vision and peripheral vision. Commonly runs in families and can be caused by defects in a number of different genes that have recently been identified	Retinitis pigmentosa (RP)
A very common disorder in which the image of the world is not clearly focused on the retina. The most common errors are: Myopia, Hyperopia, Astigmatism and Presbyopia	Refractive error
Literally 'old sight'. The age-related loss of accommodation, which makes it difficult to focus on near objects	Presbyopia
A quantum of visible light or other form of electromagnetic raiation demonstrating both particle and wave properties	Photon
Activation by light	Photoactivation
A small ganglion cell that receives excitatory inputfrom single midget bipolar cells in the central retina and feeds the parvocellular layer of the lateral geniculate nucleus	P Ganglion cell
The part of the photoreceptor that contains photopigment molecules	Outer Segment