PPMV Midterm
Name the 3 opponent channels in opponent color theory.
1. Red vs. Green 2. Blue vs. Yellow 3. Black vs. White
20/20 visual acuity measures _______ spatial frequency cut-off only.
20/20 visual acuity measures high spatial frequency cut-off only.
To convert from cycles per degree to visual acuity, take 600 and divide it by the cycles per degree.
600/CPD=VA
To convert from VA to cycles per degree, take 600 and divide it by letter distance.
600/VA=CPD
A combined plaid response occurs due to processing in __________.
A combined plaid response occurs due to processing in MT/V5.
A light source modulated at shallow modulation depth yields ______________, but temporal sinusoids at large modulation depth ___________________.
A light source modulated at shallow modulation depth yields no flicker, but temporal sinusoids at large modulation depth will flicker.
A low temporal frequency stimulus is seen as flickering at a _______________, while a high temporal frequency stimulus is seen as flickering at a _________________.
A low temporal frequency stimulus is seen as flickering at a low rate, while a high temporal frequency stimulus is seen as flickering at a high rate.
A macular lesion would show ____ EOG, ________ ffERG, _______ mfERG, and _______ VEP.
A macular lesion would show normal EOG, normal ffERG, abnormal mfERG, and abnormal VEP.
A patient with Congenital Stargardt Macular Dystrophy will have a prolonged _________ of the dark adaptation curve.
A patient with congenital Stargardt macular dystrophy will have a prolonged latter portion of the dark adaptation curve.
A photopic/cone response may be obtained on an ERG by stimulation with a _____________, single flash and __________-wavelength light.
A photopic/cone response may be obtained on ERG by stimulation with a brighter, single flash and middle-wavelength light.
A rod monochromat would show _____ rod-specific ERG, ________ maximum scotopic ERG, and ________________ photopic ERGs.
A rod monochromat would show normal rod-specific ERG, reduced maximum scotopic ERG, and undetectable photopic ERGs.
A scotopic/rod response may be obtained on an ERG by stimulation with a ___, single flash and ______ wavelength light.
A scotopic/rod response may be obtained on an ERG by stimulation with a dim, single flash and short wavelength light.
A ____________ strength is defined as one that produces a stimulus strength of 1.5 to 4.5 candelas per square meter.
A standard flash (SF) strength is defined as one that produces a stimulus strength of 1.5 to 4.5 candelas per square meter.
AMD often results in a _________ ffERG because the vision loss is contained in the macula.
AMD often results in a normal ffERG because the vision loss is contained in the macula.
Action potentials do not degrade over distance, have a ______ conduction speed, and exhibit _______ transmission.
Action potentials do not degrade over distance, have a slow conduction speed, and exhibit saltatory transmission.
Action potentials show a ___________ response, propagate over entire cell for a longer distance, no _____________, and are triggered by ______________.
Action potentials show an "all or none" response, propagate over entire cell for a longer distance, have no summation, and are triggered by threshold.
Adaptation is _________ in the retina; if you were adapting to rightward motion, the aftereffect would appear ________.
Adaptation is local in the retina; if you were adapting to rightward motion, the aftereffect would appear opposite.
Adult waveforms of VEP are developed by __ years .
Adult waveforms of VEP are developed by 5 years.
Amacrine cells are involved in the indirect transfer of signals from bipolar to ganglion cells and are the first neurons in the visual system to _____________ and _____________.
Amacrine cells are involved in the indirect transfer of signals from bipolar to ganglion cells and are the first neurons in the visual system to fire action potentials and generate transient responses.
__________ cells have a "short and sweet" response and are the first to generate action potentials.
Amacrine cells have a "short and sweet" response and are the first to generate action potentials.
Amacrine cells help _________ and _________.
Amacrine cells help code movement and detect change.
Amacrine cells receive input from one or more ________ cells, contact _______ cells, and release the __________ neurotransmitter ______.
Amacrine cells receive input from one or more bipolar cells, contact ganglion cells, and release the inhibitory neurotransmitter GABA (hyperpolarizes ganglion cells).
Amblyopes will have ____ EOGs, _____ ERGs, _____ flash VEP, and ______ pattern VEP.
Amblyopes will have normal EOGs, normal ERGs, normal flash VEP, and abnormal pattern VEP.
An Arden ration of __________ is considered abnormal while a ratio of ___________ is normal.
An Arden ratio of 1.8 or lower is abnormal, while a ratio of 2.0 or higher is normal.
Apparent/stroboscopic motion is dependent on the ____________.
Apparent/stroboscopic motion is dependent on the inter-stimulus interva (ISI).
__________ means that the brightness of a stimulus co-varies with the brightness of a surrounding stimulus.
Assimilation means that the brightness of a stimulus co-varies with the brightness of a surrounding stimulus.
Axons of the retinal ganglion cells leave the eye through the ___________, most eventually synapsing in the _________.
Axons of the retinal ganglion cells leave the eye through the optic nerve, most eventually synapsing in the LGN (parvo, magno, and bistratified).
____________ cells are the 1st in the pathway with center/surround spatial antagonism.
Bipolar cells are the 1st in the pathway with center/surround spatial antagonism.
Bipolar cells relay information from photoreceptors to _________, __________, and _____________, and receive extensive syanptic feedback from ________________.
Bipolar cells relay information from photoreceptors to horizontal, amacrine, and ganglion cells and receive extensive synaptic feedback from amacrine cells.
________ describes the reciprocal relationship between the threshold luminance (L) and time (duration of the flash, t) during the critical duration. It is written as ____________.
Bloch's Law describes the reciprocal relationship between the threshold luminance (L) and time (duration of the flash, t) during the critical duration. It is written as L*t=C.
Both "on" and "off" bipolar cells display a surround region in their receptive field that ____________ the center.
Both "on" and "off" bipolar cells display a surround region in their receptive field that opposes the center.
Both classes of horizontal cells are _________ type cells (do not discriminate color).
Both classes of horizontal cells are luminosity type cells (do not discriminate color).
Both photoreceptors and horizontal cells hyperpolarize in response to light and are therefore called ________________ synapses.
Both photoreceptors and horizontal cells hyperpolarize in response to light and are therefore called "sing-conserving" synapses.
________________ means that the brightness of objects doesn't vary despite changes in absolute luminance.
Brightness constancy means that the brightness of objects doesn't vary despite changes in absolute luminance.
___________ occurs when a change in a visual stimulus is introduced, but the observer does not notice it.
Change blindness occurs when a change in a visual stimulus is introduced, but the observer doesn't notice it.
Clinical electrophysiology consists of _____ tests which allow assessment of almost the entire length of the visual pathway.
Clinical electrophysiology consists of objective tests which allow assessment of almost the entire length of the pathway.
Clinical testing of ERG requires the following 3 electrodes: active electrode at the __________, ground electrode at the _______ or_____, and reference/inactive electrode at the ______ or_________.
Clinical testing of ERG requires the following 3 electrodes: active electrode at the cornea, ground electrode at the earlobe or forehead, and reference/inactive electrode at the forehead or temple.
Clinically, a contrast sensitivity curve may be generated using ________________, such as Arden Plates, the Vistech Vision Contrast Test System, and the Functional Acuity Contrast Test (FACT).
Clinically, a contrast sensitivity curve may be generated using gratings, such as Arden Plates, the Vistech Vision Contrast Test System, and the Functional Acuity Contrast Test (FACT).
___________________ response in an ERG may be seen in advanced cases of RP, complete retinal detachment, and Leber's congenital amaurosis.
Complete absence of response in an ERG may be seen in advanced cases of RP, complete retinal detachment, and Leber's congenital amaurosis.
Complete congenital stationary night blindness may present with _________ rod-specific ERG and __________ maximum scotopic ERG.
Complete congenital stationary night may present with undetectable rod-specific ERG and electronegative maximum scotopic ERG.
Cones adapt ___________ than rods.
Cones adapt faster than rods.
Contrast is defined as ___________________.
Contrast is defined as the ratio of the increment intensity to the background intensity.
__________ refers to our ability to process complex patterns of light and dark under a variety of luminance conditions.
Contrast refers to our ability to process complex patterns of light and dark under a variety of luminance conditions.
Critical flicker frequency is highest at ____________ and decreases as eccentricity _________.
Critical flicker frequency is highest at central fixation and decreases as eccentricity increases.
Decreasing the duration of the adapting light may reduce or eliminate the ___________ portion of the dark adaptation curve.
Decreasing the duration of the adapting light may reduce or eliminate the photopic/cone portion of the dark adaptation curve.
Detection of a higher luminance region against a lower illuminated field is ________ threshold task.
Detection of a higher luminance region against a lower illuminated field is an increment threshold task.
Detection of a lower luminance region against a higher illuminated luminance field is ________ threshold task
Detection of a lower luminance region against a higher illuminated luminance field is a decrement threshold task.
_____________ Bipolar cells contact about 5 neighboring cones in the central retina, may contact more than 1 type of cone, and contact about 10-15 neighboring cones in the periphery.
Diffuse Bipolar cells contact about 5 neighboring cones in the central retina, may contact more than 1 type of cone, and contact about 10-1 neighboring cones in the periphery.
_________ bipolar cells are non-color opponent, while _____________ bipolar cells are color opponent.
Diffuse bipolar cells are non-color opponent, while midge bipolar cells are color opponent.
ERG for a patient with retinitis pigmentosa may show early ____ dysfunction with residual _____ physiology.
ERG for a patient with RP may show early rod dysfunction with residual cone physiology.
ERG may be affected by _______, ______, and _______.
ERG may be affected by type of electrode, media clarity, and diurnal changes.
___________ are a group of electrodiagnostic tests to assess the integrity of the retina and its central connections.
ERGs or electroretinograms are a group of electrodiagnostic tests to assess the integrity of the retina and its central conductions.
______________ is an early, small, fast biphasic potential, which occurs before standard ERG responses, originates in the photoreceptor outer segments, and needs a brighter stimulus to be elicited.
Early Receptor Potential (ERP) is an early, small, fast, biphasic potential which occurs before standard ERG responses, originates in the photoreceptor outer segments, and needs a brighter stimulus to be elicited.
______ order motion is a simple linear exchange of light for dark, is also called apparent motion, and examples include stroboscopic and sine wave grating shifts.
First order motion is a simple linear exchange of light for dark, is also called apparent motion, and examples include stroboscopic and sine wave grating shifts.
________ ERG can help detect damage in a localized area of the retina by flashing a light only on the area of interest.
Focal ERG can help detect damage in localized area of the retina by flashing a light only on the area of interest.
For Off-center bipolar cells the glutamate receptor is called _______, which is _________ by glutamate.
For Off-center bipolar cells the glutamate receptor is called Amp, which is excited by glutamate.
For On-center bipolar cells the glutamate receptor is called __________, which is _____________ by glutamate.
For On-center bipolar cells the glutamate receptor is called Mglue6, which is inhibited by glutamate.
For the temporal modulation transfer function, the percent modulation at which a person first detects a flicker is the __________ and its reciprocal forms the _-axis of the function.
For the temporal modulation transfer function (TMTF), the percent modulation at which a person first detects a flicker is the threshold and its reciprocal forms the y-axis of the function.
_____________ has shown that the visual system has independent spatial frequency channels which are summed together to form the contrast sensitivity function.
Fourier analysis has shown that the visual system has independent spatial frequency channels which are summed together to form the contrast sensitivity function.
________________ is a method to define periodic waveforms by trigonometric function, often used in electronics, acoustics, and communications.
Fourier analysis is a method to define periodic waveforms by trigonometric function, often used in electronics, acoustics, and communications.
Foveal cones subtend a visual angle of about ___ minutes of arc (______ arc sec).
Foveal cones subtend a visual angle of about 0.5 minutes of arc (30-40 seconds of arc)
Full-field Electroretingram is elicited by a ______ stimulus which evenly illuminates the _________ , recording a biphasic waveform of summed transient electrical responses. The potential of an ffERG is about ___mV.
Full-field electroretinogram is elicited by a 5ms flash stimulus which evenly illuminates the entire retina, recording a biphasic waveform of summed transient electrical responses. The potential of an ffERG is about 1 mV.
Ganglion cells in the periphery integrate information from a ______ area (_ degrees), while ganglion cells in the fovea integrate information from a _______ area (___ degrees).
Ganglion cells in the periphery integrate information from a large area (3 degrees), while ganglion cells in the fovea integrate information from a small area (.03 degrees).
__________ is defined as when ambient light interferes with increment or different threshold detections.
Glare is defined as when ambient light interferes with increment or different threshold detections.
Glaucoma would result in ______ EOG, ______ ERG, ____ VEP early, and ______ VEP late.
Glaucoma would result in normal EOG, normal ERG, normal VEP early, and abnormal VEP late.
Graded potentials have a _________ response dependent on stimulus, __________ with distance, may have _________, and are triggered by __________.
Graded potentials have a graded response dependent on stimulus, decrease with distance, may have summation, and are triggered by stimulus.
Grating acuity is _________ impacted by optical defocus than a standard letter chart.
Grating acuity is less impacted by optical defocus than a standard letter chart.
H1 horizontal cells (B type) receive input primarily from ___ and ___ cones, regulate adaptational and spatial responses of ______ and ______ cells, and connect to ________ in the dendritic field and _______ at the distal end.
H1 horizontal cells receive input primarily from M and L cones, regulate adaptational and spatial responses of cones and bipolar cells, and connect to cones in the dendritic field and rods at the distal end.
H2 horizontal cells receive input from _________ type cones and do not connect to _________.
H2 horizontal cells (A type) receive input from all type cones and do not connect to rods.
Horizontal cells release an __________ neurotransmitter, _______, in a graded fashion in response to depolarization by the photoreceptors.
Horizontal cells release an inhibitory neurotransmitter, GABA, in a graded fashion in response to depolarization by the photoreceptors.
Horizontal transmission of retinal information is accomplished by the ________ __________ and ________ cells.
Horizontal transmission of retinal information is accomplished by the inhibitory horizontal and amacrine cells.
Humans have peak spatial contrast sensitivity at _ to _ cycles per degree,
Humans have peak contrast sensitivity at 3-10 cycles per degree.
ISCEV requires the following photopic ffERG responses: _________ and __________.
ISCEV requires the following photopic ffERG responses: single flash cone response and 30 Hz flicker cone response.
ISCEV requires the following scotopic ffERG responses: _________, ___________, and _________.
ISCEV requires the following scotopic ffERG responses: rod response, maximal combined rod and cone response, and oscillatory potentials.
ISCEV standards suggest ___ minutes of dark adaptation to obtain the _ scotopic ERG readings, followed by __ minutes of light adaptation to obtain the __ photopic readings.
ISCEV standard suggest 20 minutes of dark adaptation to obtain the 3 scotopic readings, followed by 10 minutes of light adaptation to obtain the 2 photopic readings.
ISCEV stands for ___________, and it establishes standards for ______, ______, and ______ which are reviewed every three years.
ISCEV stands for the International Society for Clinical Electrophysiology of Vision and it establishes standard for ERG, EOG, and VEP which are reviewed every 3 years.
_________ refers to the ability to recognize the smallest details in a letter or picture and is the most common clinically measured form of spatial acuity.
Identification/Recognition acuity refers to the ability to recognize the smallest details in a letter or picture and is the most common clinically measured form of spatial acuity.
If the flash stimulus is red, the __________ portion of the dark adaptation curve is eliminated.
If the flash stimulus is red, the scotopic/rod portion of the dark adaptation curve is eliminated.
If the flash stimulus is violet, the ____________ portion of the dark adaptation curve is extended.
If the flash stimulus is violet, the scotopic/rod portion of the dark adaptation curve is extended.
If the optics transmits a perfect image at all spatial frequencies (i.e. image contrast=object contrast), MTF=____.
If the optics transmits a perfect image at all spatial frequencies (i.e. image contrast=object contrast), MTF=1.
_______ times measure from the flash onset to the trough of the a-wave or the peak of the b-wave.
Implicit times measure from the flash onset to the trough of the a-wave or the peak of the b-wave.
In Central Visual Pathway Disorders, such as Multiple Sclerosis there may be loss of contrast at ______ spatial frequencies which do not correlate with a loss in VA.
In Central Visual Pathway Disorders, such as Multiple Sclerosis, there may be loss of contrast at low spatial frequencies which do not correlate with a loss in VA.
In amblyopia, there is contrast loss at _____ to ___ spatial frequencies, which correlate to reduction in VA.
In amblyopia, there is contrast loss at mid to high spatial frequencies, which correlate to reduction in VA.
In glaucoma, __________ measures the ability to detect high temporal frequency for flicker detection.
In glaucoma, FDT (frequency doubling task) in visual fields measures the ability to detect high temporal frequency for flicker detection.
In _________ the visibility of a target is reduced by the subsequent presentation of a spatially adjacent mask.
In metacontrast, the visibility of a target is reduced by the subsequent presentation of a spatially adjacent mask.
In order to achieve a square wave grating from sine wave gratings, the __________ frequency must be combined will all the ____ harmonics.
In order to achieve a square wave grating from sine wave gratings, the fundamental frequency must be combined with all the odd harmonics.
In stroboscopic motion, an interval of 60 ms produces _________.
In stroboscopic motion an interval of 60 ms produces a realistic sensation of spot moving from point a to point b (optimum or beta movement).
In stroboscopic motion, an interval of less than 30 ms produces ________.
In stroboscopic motion, an interval of less than 30ms produces no sensation of movement.
In stroboscopic motion, durations of 60 to 200 ms produce ______________.
In stroboscopic motion, durations of 60 to 200 ms produce a partial illusion of movement (pure or phi movement).
In the absence of light, photoreceptors become __________ and glutamate is _______________.
In the absence of light, photoreceptors become more depolarized and glutamate is released.
In the dark current, __ ions flow into the rod outer segment through channels and produce slight ___________.
In the dark current, Na+ ions flow into the rod outer segment through channels and produce slight depolarization.
In the first section of the TVI curve of light adaptation, the ________ section, the slope = ________.
In the first section of the Threshold vs. Intensity curve of light adaptation, the dark light section, the slope = 0.
In the fourth section of the TVI curve of light adaptation, the ________ section, the slope = ____________.
In the fourth section of the TVI curve of light adaptation, the Rod Saturation section, the slope = infinite.
In the macular photostress recover test, a normal macula will recover in __ seconds, a diseased macula may require _________ to recover, and problems outside the macula will ____________________.
In the macular photostress recover test, a normal macula will recover in 60 seconds, a diseased macula may require 1.5-3+ minutes to recover, and problems outside the macula will not affect recovery.
In the presence of light, photoreceptors become ___________ and glutamate is ____________.
In the presence of light photoreceptors become more hyperpolarized and glutamate is NOT released.
In the second section of the TVI curve of light adaptation, the _______ section, the slope= _________.
In the second section of the TVI curve of light adaptation, the Square Root Law/DeVries-Rose Law section, the slope = 1/2.
In the third section of the TVI curve of light adaptation, the __________ section, the slope = __________.
In the third section of the TVI curve of light adaptation, the Weber's Law section, the slope = 1.
In the visual system, a retinal __________ is the region of visual space that makes a neuron change its firing under the presence of a certain visual stimulus.
In the visual system, a retinal receptive field is the region of visual space that makes a neuron change its firing under the the presence of a certain visual stimulus.
Increasing the flash stimulus size will result in a __________ rod response in the dark adaptation curve.
Increasing the flash stimulus size will result in an earlier rod response in the dark adaptation curve.
__________ refers to the time between the onset of the stimulus and the beginning of the a-wave response (about 2 msec).
Latency refers to the time between the onset of the stimulus and the beginning of the a-wave response (about 2 msec).
Localization acuity ranges from _ to_ arc seconds, finer than spacing between foveal photoreceptors, and has a __________ mechanism.
Localization acuity ranges from 2-6 arc seconds, finder than the spacing between foveal photoreceptors, and has a nueral mechanism.
__________ refers to the smallest spatial offset or difference in location between targets that can be discriminated.
Localization/hyperacuity refers to the smallest spatial offset or difference in location between targets that can be discriminated.
Long wavelength flash stimuli may make the rod-cone break __________________, while short wavelength flash stimuli may make the rod-cone break _______________ in the dark adaptation curve.
Long wavelength flash stimuli may make the rod-cone break disappear, while short wavelength flash stimuli may make the rod-cone break more prominent in the dark adaptation curve.
__________cut-off of the contrast sensitivity function is due to the center/surround responses of ganglion cells.
Low frequency cut-off of the contrast sensitivity function is due to the center/surround responses of ganglion cells.
Low frequency sensitivity reduction is due to _______________.
Low frequency sensitivity reduction is due to lateral inhibition interactions, as center-surround effects cancel each other.
Lowering the luminance of the adapting light may reduce or eliminate the _________ portion of the dark adaptation curve.
Lowering the luminance of the adapting light may reduce or eliminate the photopic/cone portion of the dark adaptation curve.
__________ refer to the emphasized contrast boundaries associated with edges which are accentuated by the retinal ganglion cells which have center-surround receptive fields.
Mach bands refer to the emphasized contrast boundaries associated with edges which are accentuated by the retinal ganglion cells which have center-surround receptive fields.
___________ means that a brief display that is clearly visible when shown alone can be rendered invisible by the subsequent presentation of second visual stimulus.
Masking means that a brief display that is clearly visible when shown alone can be rendered invisible by the subsequent presentation of a second visual stimulus.
Maximum sensitivity to flicker increases as ____________ increases.
Maximum sensitivity to flicker increases luminance level increases.
_______________ area neurons respond to speed patterns in optic flow.
Medial superior temporal (MST) area neurons respond to speed patterns in optic flow.
Medial temporal neurons (MT) are __________ selective, each responds best to a preferred speed and selection, within its receptive field, independent of stimulus pattern.
Medial temporal neurons (MT) are velocity selective, each responds best to a preferred speed and selection, within its receptive field, independent of stimulus pattern.
Midget ganglion cells are found only in the _______, synapse with only 1 bipolar cell and photoreceptor, receive input mainly from ______, have a _______ response to light, allow for high ____ resolution, and are ______ sensitive.
Midget (retinal parvo) ganglion cells are found only in the fovea, synapse with only 1 bipolar cell and photoreceptor, receive input mainly from cones, have a sustained response to light, allow for high spatial resolution, and are color sensitive.
_____________ ganglion cells project to the parvocellular layers of the lateral geniculate nucleus.
Midget (retinal parvo) ganglion cells project to the parvocellular layers of the lateral geniculate nucleus.
___________ bipolar cells (M-cone or L-cone input) contact only 1 cone in the central and mid-peripheral retina, but receive input from more than 1 cone in the periphery.
Midget bipolar cells(M-cone or L-cone input) contact only 1 cone in the central and mid-peripheral retina, but receive input from more than 1 cone in the periphery.
Minimal detectable acuity refers to the angular size of the smallest object that can just be seen, is a type of ________ threshold, and depends more on _______________ than ________.
Minimal detectable acuity refers to the angular size of the smallest object that can just be seen, is a type of increment threshold, and depends more on luminance/contrast of the retinal image than angular size.
Most conditions which would produce an abnormal Arden ratio on EOG would also produce and abnormal __________. The exceptions are ________, ___________, _________, and _________.
Most conditions which produce an abnormal EOG Arden ration also produce an abnormal ERG. The exceptions are butterfly dystrophy of the fovea, fundus flavimaculatus, advanced drusen, and vitelliform dystrophy (Best's disease).
Most motion we observe is _________ or ________ or _______, when 2 or more lighted stimuli that are switched on and off in alternation can produce a type of 'motion perception.'
Most motion we observe is apparent or illusory or stroboscopic, when 2 or more lighted stimuli that are switched on and off in alternation can produce a type of 'motion perception.'
Motion coherence may be used to assess ___________ function, as the neurons won't fire unless the specific direction and speed are evident.
Motion coherence may be used to assess MT (medial temporal) function, as the neurons won't fire unless the specific direction and speed are evident.
Moving the flash stimulus away from the point of fixation will reduce the length of the ________ portion of the dark adaptation curve.
Moving the flash stimulus away from the point of fixation will reduce the length of the photopic/cone portion of the dark adaptation curve.
________ assesses small or localized optic nerve pathway problems using a a changing pattern of discrete flashes, measures about 25 degrees of visual field, and produces spatially discrete patterns of response.
Multifocal VEP assesses small or localized optic nerve pathway problems using a changing pattern of discrete flashes, measures about 25 degrees of visual field, and produces spatially discrete patterns of response.
Myopia may result in a linear decrease in _____________ on the ERG.
Myopia may result in a linear decrease in b-wave amplitudes on the ERG.
Myopic astigmatism at axis 180 causes defocus of ________ contours.
Myopic astigmatism at axis 180 causes defocus of vertical contours.
___ of the mfERG receives contributions from the same cells as light-adapted a-wave, while ___ and ___ receive contributions from the same cells as the light-adapted b-wave and oscillatory potentials. However, these waves are NOT equivalent; the mfERG waveform is a _____________.
N1 of the mfERG receives contributions from the same cells as the light-adapted a-wave, while P1 and N2 receive contributions from the same cells as the light-adapted b-wave and oscillatory potentials. However, these waves are NOT equivalent. The mfERG waveform is a mathematical approximation.
_____ of the PERG is the immediate corneal negative response and correlates to ganglion cell function.
N95 of the Pattern ERG is the immediate corneal negative response and correlates to ganglion cell function.
____________ refers to the compression of information from over a hundred million photoreceptors to the million ganglion cells.
Neural convergence refers to the compression of information from over a hundred million photoreceptors to the million ganglion cells.
Neurons in the medial temporal area (MT) of the visual cortex are selective for ________, receive input from ____________, and can cause ______________ if damaged or inactivated.
Neurons in the medial temporal area (MT) of the visual cortex are selective for motion direction, receive input from direction-selective neurons in V1, and can cause visual motion perception deficits if damaged or inactivated.
Off Center Bipolar cells ____________ in response to less glutamate, resulting in _____________ glutamate release from the Off Center bipolar cell, and ___________ of the ganglion cell.
Off bipolar cells hyperpolarize in response to less glutamate, resulting in decreased glutamate release from the Off Center bipolar cell, and inhibition of the ganglion cell.
___ ganglion cells respond when a light is removed from the retina.
Off ganglion cells respond when a light is removed from the retina.
Off-Center bipolar cells have an ___-Surround and ______________ synapse with photoreceptors in the outer plexiform layer.
Off-Center bipolar cells have an On-Surround and a conventional flat synapse with photoreceptors in the outer plexiform layer.
Off-center bipolar cells synapse with ganglion cells in the __________ sublayer (sublamina _) of the the inner plexiform layer.
Off-center bipolar cells synapse with ganglion cells in the outer sublayer (sublamina a) of the inner plexiform layer.
On Center Bipolar cells __________ in response to less glutamate, resulting in ________________ glutamate release from the on center bipolar cell, and ___________ of the ganglion cell.
On Center Bipolar cells depolarize in response to less glutamate, resulting in increased glutamate release from the the On Center bipolar cell, and excitation of the ganglion cell.
_____ ganglion cells respond when a light strikes the retina.
On ganglion cells respond when a light strikes the retina.
On the temporal modulation transfer function, ____________ (y-axis) is plotted as a function of ____________ (x-axis).
On the temporal modulation transfer function, 1/% modulation (y-axis) is plotted as a function of temporal frequency (x-axis).
On-Center bipolar cells have an ___-Suround and an __________ synapse with photoreceptors in the outer plexiform layer.
On-Center bipolar cells have an Off-Surround and an invaginating synapse with photreceptors in the outer plexiform layer.
On-center bipolar cells synapse with ganglion cells in the ___________ sublayer (sublamina _) of the inner plexiform layer.
On-center bipolar cells synapse with ganglion cells in the inner sublayer (sublamina b) of the inner plexiform layer.
On-center ganglion cells synapse with __-center bipolar cells.
On-center ganglion cells synapse with on-center bipolar cells.
____ ganglion cells respond briefly when the light is on and again briefly when the light is switched off.
On/off ganglion cells respond briefly when the light is on and again briefly when the light is switched off.
______________- refers to the changing pattern of apparent motion and is an estimation of self-motion between the observer and scene.
Optic flow refers to the changing pattern of apparent motion and is an estimation of self-motion between the observer and the scene
______________ increases hyperacuity thresholds if targets are very close together, but has less effect if objects are farther apart (1 degree).
Optical defocus increases hyperacuity thresholds if targets are very close together, but has less effect if objects are farther apart (1 degree).
Orientation selectivity begins at area ___ of the ___ lobe.
Orientation selectivity begins area V1 of the occipital lobe.
Oscillatory potential abnormalities indicate that __________ cells in the inner plexiform layer may be affected by ischemic retinopathy.
Oscillatory potential abnormalities in the ERG indicate that amacrine cells in the inner plexiform layer may be affected by ischemic retinopathy.
___________ are 3-4 small wavelets occurring on the rising phase of the b-wave which reflect activity of amacrine cells in the inner plexiform layer.
Oscillatory potentials (Ops) are 3-4 small wavelets occurring on the rising phase of the b-wave which reflect activity of the amacrine cells in the inner plexiform layer.
_________ are delayed in patients with diabetes and retinal ischemia, also seen in CRAO.
Oscillatory potentials are delayed in patients with diabetes and retinal ischemia, also seen in CRAO.
___ of VEP is recordable with <200 msec latency at 5 weeks.
P1 of VEP is recordable with <200 msec latency at 5 weeks.
_______ of the PERG is the initial corneal positive response and correlates to macular function.
P50 of the Pattern ERG is the initial corneal positive response and correlates to macular function.
Parasol ganglion cells have ______ surrounds, synapse with multiple bipolar cells and photoreceptors, receive input mostly from ________, have a ________ response to light, allow for good ______ resolution, and are not _______ sensitive.
Parasol (retinal magno) ganglion cells have large surrounds, synapse with multiple bipolar cells and photoreceptors, receive input mostly from rods, have a transient response to light, allow for goo temporal resolution, and are not color sensitive.
_______ ganglion cells project to the magnocellular layers of the LGN.
Parasol (retinal magno) ganglion cells project to the magnocellular layers of the LGN.
Patients with ARMD will show _____________ on the dark adapatation curve.
Patients with ARMD will show progressively longer dark times on the dark adaptation curve.
Patients with multiple sclerosis will have ____ ERGs, ____ flash VEP, and ____ pattern VEP.
Patients with MS will have normal ERGs, abnormal flash VEP, and abnormal pattern VEP.
Patients with Oguchi disease will show ________ on the dark adaptation curve.
Patients with Oguchi disease will show an extremely prolonged scotopic protion ofnthe dark adaptation curve.
Patients with choroideremia will show ________ on the dark adaptation curve.
Patients with choroideremia will show an absent scotopic portion of the dark adaptation curve.
Patients with fundus albipunctatus will show___________ on the dark adaptation curve.
Patients with fundus albipunctatus will show normal final rod and cone thresholds, but lengthened rates of the dark adaptation curve.
Patients with retinitis pigmentosa will show ________ on the dark adaptation curve.
Patients with retinitis pigmentosa will show an elevated or absent scotopic/rod portion on the dark adaptation curve.
Pattern ERG originates in the retinal ganglion cells of the inner retina and helps distinguish between _________ and _______ disease in patients with poor VA.
Pattern ERG originates in the retinal ganglion cells of the inner retina and helps distinguish between optic nerve and macular disease in patients with poor VA.
Pattern ERG uses a _________ modulated checkerboard pattern with constant luminance to measure _______ function (P50) and ________ cell function (N95).
Pattern ERG uses a temporally modulated checkerboard pattern with constant luminance to measure macular function (P50) and ganglion cell function (N95)
_____________ VEP uses checks which alternately disappear and reappear.
Pattern Onset/Offset VEP uses checks which alternately disappear and reappear.
________ VEP uses high contrast checks which allow for estimation of VA, and elicits the largest amplitude and fastest peak latency when the check size is the smallest that the patient can see clearly.
Pattern VEP uses high contrast checks which allow for estimation of VA and elicits the largest amplitude and fastest peak latency when the check size is the smallest that the patient can see clearly. Peak is called P1 or P100.
_________ is the amount by which the flash luminance deviates from the mean luminance, is analogous to spatial resolution acuity, and is written as ________________.
Percent modulation is the amount by which the flash luminance deviates from the mean luminance, is analogous to spatial resolution acuity, and is written as %Modulation=(Amplitude/Lavg)*100
Photopic ERG b-wave amplitude is adult-like at ________ and latency is adult-like at __________.
Photopic ERG b-wave amplitude is adult-like at 2 months and latency is adult-like at 1 year.
_______________ resolution and contrast sensitivity is greater, but the ability to detect a low level stimulus, absolute sensitivity, is greater under __________ conditions.
Photopic resolution and contrast sensitivity is greater, but the ability to detect a low level stimulus, absolute sensitivity, is greater under scotopic conditions.
____________ temporal resolution is greater than _________ temporal resolution.
Photopic temporal resolution is greater than scotopic temporal resolution.
Photoreceptors are ______ order neurons.
Photoreceptors are 1st order neurons.
Photoreceptors are slightly __________ relative to a typical neuron.
Photoreceptors are slightly depolarized relative to a typical neuron. (-50 mV vs -70 mV resting membrane potential)
Photoreceptors _________ and generate a _________ potential to prevent the bipolar cells from ____________ in the absence of light.
Photoreceptors depolarize and generate a graded potential to prevent the bipolar cells from depolarizing and activating ganglion cells in the absence of light.
Photoreceptors synapse with ______ cells and _____ cells in the ________ layer.
Photoreceptors synapse with bipolar cells and horizontal cells in the outer plexiform layer.
Photoreceptors, horizontal cells, and bipolar cells have ________ potentials, while amacrine cells and ganglion cells have ________ potentials.
Photoreceptors, horizontal cells, and bipolar cells have graded potentials, while amacrine cells and ganglion cells have action potentials.
Photoreceptors, horizontal cells, and bipolar cells have _______ not __________.
Photoreceptors, horizontal cells, and bipolar cells have graded responses, not action potentials.
______________ describes spatial summation for stimuli up to 24 degrees in diameter. It is written as __________.
Piper's Law describes spatial summation for stimuli up to 24 degrees in diameter. It is written as L*√A=C.
Random dot kinematograms measure motion ____________, which humans can detect thresholds of at as low as 1%.
Random dot kinematograms measure motion coherence, which humans can detect thresholds of at as low as 1%.
______________ require global motion perception, integration of motion cues across a wide expanse of the visual field simultaneously, and may test for early magnocellular loss in glaucoma.
Random dot kinematograms require global motion perception, integration of motion cues across a wide expanse of the visual field simultaneously, and may test for early magnocellular loss in glaucoma.
Receptive fields overlap, meaning a small spot of light will excite or inhibit many ganglion cells, and allowing for _______ mapping and the determination of _______.
Receptive fields overlap, meaning a small spot of light will excite or inhibit many ganglion cells, and allow for 'spot mapping' and the determination of shapes.
_________ acuity is most affected by optical defocus.
Recognition acuity is most affected by optical defocus.
Relative luminance differences are _______ important than absolute luminance to the human visual system.
Relative luminance differences are more important than absolute luminance to the human visual system.
Resolution acuity depends on the ____ of the eye and the ____ of the photoreceptors.
Resolution acuity depends on the optics of the eye and the spacing of the photoreceptors.
_____________ acuity refers to the smallest spatial separation between two nearby points or lines that can be discriminated as 2 vs. 1.
Resolution acuity refers to the smallest spatial separation between two nearby points or lines that can be discriminated as 2 vs. 1.
Retinal bipolar cells are ____ order neurons.
Retinal bipolar cells are 2nd order neurons.
Retinal ganglion cell axons which synapse in the superior colliculus are involved in ____________, while those that synapse in the pulvinar region are involved in _________, ________, and ___________.
Retinal ganglion cell axons which synapse in the superior colliculus are involved in eye movements, while those that synapse in the pulvinar region are involved in visual attention, motion processing, and visually guided behavior.
Do retinal ganglion cells produce graded potentials or full action potentials?
Retinal ganglion cells produce full action potentials when the release of glutamate by the bipolar cells is sufficient to depolarize them to threshold.
Retinitis pigmentosa would result in _______ EOG, _______ ERG, and ______ VEP.
Retinitis pigmentosa would result in abnormal EOG, abnormal ERG, and normal VEP.
________________ is a mathematic representation of spatial summation, which states that for small areas (<10 minutes), there is a reciprocal relationship between threshold luminance and stimulus area.
Ricco's Law (L*A=C) is a mathematic representation of spatial summation, which states that for small areas (<10 minutes), there is a reciprocal relationship between threshold luminance (L) and stimulus area (A).
__________ bipolar cells do not contact ganglion cells directly, but are instead mediated by amacrine or cone bipolar cells.
Rod bipolar cells do not contact ganglion cells directly, but are instead mediated by amacrine or cone bipolar cells.
Rods and cones both start dark adaptation at the same time, _______________.
Rods and cones both start dark adaptation at the same time, Time Zero.
Rods are __________ sensitive than cones.
Rods are more sensitive than cones.
Rods are ________ to dark adapt than cones, but have _________ light sensitivity.
Rods are slower to dark adapt than cones, but have greater light sensitivity
Rods can't see _____ light, but _______ appears brighter to rods than cones.
Rods can't see red light, but blue/green appears brighter to rods than cones.
_________ have great sensitivity, but poor resolution, while _______ have poor sensitivity, but great resolution.
Rods have great sensitivity, but poor resolution, while cones have poor sensitivity, but great resolution.
_____________ bipolar cells synapse onto bistratified ganglion cells and respond to only 1 cone in the central retina.
S-Cone bipolar cells synapse onto bistratified ganglion cells and respond to only 1 cone in the central retina.
___________ occurs when vision is suppressed slightly before, during, and slightly after a saccade in order to prevent image smear and is caused selective inhibition of the __________ pathway.
Saccadic omission occurs when vision is suppressed slightly before, during, and slightly after a saccade in order to prevent image smear, and it is caused by selective inhibition of the magnocellular pathway.
_________ transmission refers to the regeneration of action potentials along the myelin sheath in a ganglion cell axon at the nodes of Ranvier.
Saltatory transmission refers to the regeneration of action potentials along the myelin shealth in a ganglion cell axon at the nodes of Ranvier.
Scotopic ERG b-wave amplitude is adult-like at __________, latency is adult-like at ______, and amplitudes _______ with age after age 10.
Scotopic ERG b-wave amplitude is adult-like at 6 months, latency is adult-like at 1 year, and amplitudes decrease with age from 10 years.
________ spatial summation is superior to _______ spatial summation.
Scotopic spatial summation is superior to photopic spatial summation.
___________ temporal summation is greater than ________ temporal summation.
Scotopic temporal summation is greater than photopic temporal summation.
_______ order motion involves higher cortical centers and refers to motion in which the 'moving' contour is defined by contrast, texture, flicker or some other quality that does NOT result in an increase in luminance or motion energy in the spectrum of the stimulus.
Second order motion involves higher cortical centers and refers to motion in which the 'moving' contour is defined by contrast, texture, flicker, or some other quality that does NOT result in an increase in luminance or motion energy in the spectrum of the stimulus.
__________ is the trade-off between absolute and relative sensitivity.
Sensitivity regulation is the trade-off between absolute and relative sensitivity.
Shorter wavelength adapting lights will show _________ cone adaptation and longer wavelength adapting lights show _________ cone adaptation in the dark adaptation curve.
Shorter wavelength adapting lights will show rapid cone adaptation and longer wavelength adapting lights show prolonged cone adaptation in the dark adaptation curve.
_________ cells synapse with regards to bipolar and ganglion cells.
Similar cells synapse with regard to bipolar and ganglion cells, i.e. on-center to on-center, midget-bipolar cells to midget-ganglion cells, and diffuse-bipolar cells to parasol-ganglion cells.
____________ means that the relative brightness of an object increases or decreases depending on the background.
Simultaneous contrast means that the relative brightness of an object increases or decreases depending on the background.
______________ are alternating white and black bars with gradual or 'sinusoidal' transitions from dark to light.
Sine wave gratings are alternating white and black bars with gradual or 'sinusoidal' transitions from dark to light.
Sine wave gratings that undergo _________ can also produce motion.
Sine wave gratings that undergo a phase shift can also produce motion.
Sine waves of appropriate __________, ____________, __________, and _______ can be used to construct any other spatial stimulus.
Sine waves of appropriate frequency, contrast, phase, and orientation can be used to construct any other spatial stimulus.
Spatial summation is defined as ____________.
Spatial summation is defined as the eye's ability to add together quanta over a specific area.
____________ refers to the phenomenon in center/surround cells, whereby the maximal response can be evoked only with an optimally sized spot.
Spatial tuning refers to the phenomenon in center/surround cells, whereby the maximal response can be evoked only with an optimally sized spot.
Spatial visual acuity may refer to the smallest detail we can see by ___________, ___________, __________, or ___________.
Spatial visual acuity may refer to the smallest detail we can see by detection, localization, resolution, or identification.
___________ or ___________ refers to the fact the retinal ganglion cells are always active. Even when they are not stimulated they send signals at a rate of 5-40/sec ( visual signals are superimposed on this background).
Spontaneous activity or maintained discharge refers to the fact that the retinal ganglion cells are always active. Even when they are not stimulated they send signals at a rate of 5-40/sec (visual signals are superimposed on this background).
Stargardt macular dystrophy presents with progressively ___________ response photopic and scotopic ERGs.
Stargardt macular dystrophy presents with progressively subnormal response photopic and scotopic ERGs.
________ responses in an ERG indicate that a large area of the retina is not functioning, as in early RP, retinal detachment, chloroquine toxicity, and etc.
Sub-normal responses in an ERG indicate that a large area of the retina is not functioning, as in early RP, retinal detachment, chloroquine toxicity, and etc.
__________ responses in an ERG are characterized by a potential above the normal upper limit, such as in early siderosis bulbi.
Super-normal responses in an ERG are characterized by a potential above the normal upper limit, such as in early siderosis bulbi.
______ VEP rapidly measure VA or contrast using a stimulus with varying contrast and grating.
Sweep VEP rapidly measures VA or contrast using a stimulus with varying contrast and grating.
__________ states that the brightness of a fused temporally modulated stimulus is equal to the brightness of a steady light of the same average luminance.
Talbot-Plateau Law states that the brightness of a fused temporally modulated stimulus is equal to the brightness of a steady light of the same average luminance.
The __% contrast low contrast chart is the most practical low contrast chart, clinically.
The 2.5% low contrast chart is the most practical low contrast chart, clinically.
The __________ means that flashes of pulse duration __________ are perceived as brighter than stimuli with a duration of less than or greater than this value.
The Broca-Sulzer Effect means that flashes of pulse duration 50-100 msec are perceived as brighter than stimuli with a duration of less than or greater than this value.
The ___________ is the temporal analogue to minimum angle of resolution in the spatial domain, i.e. the minimum temporal separation between successive flashes of light that are just resolvable into a flicker of 2 lights.
The Critical Flicker Frequency (CFF) is the temporal analogue to minimum angle of resolution in the spatial domain, i.e. the minimum temporal separation between successive flashes of light that are just resolvable into a flicker of 2 lights.
The DeVries-Rose Law states that ______________.
The DeVries-Rose Law states that for the second section of the TVI curve, Increment Threshold= (Background Intensity)^(1/2)..
The EOG amplitude ________ with dark adaptatiion, with a dark ______ at about _______ minutes into dark adaptation.
The EOG amplitude decreases with dark adaptation, with a dark trough at about 12 minutes into dark adaptation.
The EOG amplitude _________ with light adaptation, with a light ______ at about _______ minutes from the onset of light adaptation.
The EOG amplitude increases with light adaptation with a light peak at about 7-12 minutes from the onset of light adaptation.
The EOG is decreased when the _____ and/or connections to the ________ are disrupted, such as in retinal detachment, or degenerative disease.
The EOG is decreased the RPE and/or connections to the photoreceptors are disrupted, such as in retinal detachment, or degenerative disease.
The EOG measures transepithelial potential of the ____.
The EOG measures the transepithelial potential of the RPE.
The ERG is a _______ measure of electrical responses produced by the retina when stimulated by sufficiently intense light.
The ERG is a corneal measure of electrical responses produced by the retina when stimulated by sufficiently intense light.
The ERG is abnormal only if more than _____% of the retina is affected. The ERG generally reflects ______ retinal function.
The ERG is abnormal only if more than 30-40% of the retina is affected. The ERG generally reflects peripheral retinal function
The ______________ law states that the critical flicker frequency is directly proportional to the log of stimulus luminance.
The Ferry-Porter law states that the critical flicker frequency (CFF) is directly proportional to log of stimulus luminance, i.e. brighter lights have CFF at higher frequencies.
The ______ VEP is used when pattern VEP is not an option, or there is poor VA or fixation. It results in a complex series of waves with a prominent N2 trough at 70-90 msec and P2 peak at 100-120 msec.
The Flash VEP is used when pattern VEP is not an option or there is poor VA/fixation. It results in a complex series of waves with a prominent N2 trough at 70-90 msec and P2 peak at 100-120 msec.
How does the Functional Acuity Contrast Test differ from the Vistech Vision Contrast Test System?
The Functional Acuity Contrast Test is on background of similar luminance to the sine wave gratings, while the Vistech test is on a background which contrasts with its sine wave gratings.
The ________ law states that critical flicker frequency increases with the log of stimulus area, so flicker is more likely to be perceived if the stimulus is _________.
The Granit-Harper law states that critical flicker frequency increases with the log of stimulus area, so flicker is more likely to be perceived if the stimulus is large.
The ________ and ______________ charts are multiple contrast charts, which have varying contrasts, but the same sized letters throughout the chart.
The MARS and Pelli Robson charts are multiple contrast charts, which have varying contrasts, but the same sized letters throughout the chart.
The Michaelson formula for contrast of gratings is written as ______________________.
The Michaelson formula for contrast of gratings is written as Contrast= (Lmax-Lmin)/(Lmax+Lmin).
The ____________ refers to the ability of an optical system to transmit spatial frequencies and describes _____ performance.
The Modulation Transfer Function (MTF) refers to the ability of an optical system to transmit spatial frequencies and describes lens performance.
The Purkinje tree is only seen if _________.
The Purkinje tree is only seen if the light moves.
The ____________ refers to the fading of an image that is seen in the peripheral visual field.
The Troxler effect refers to the fading of an image that is seen in the peripheral visual field.
The ___________________, may be performed at distance or near, and consists of 5 rows of sine wave gratings with different spatial frequencies and contrasts.
The Vistech Vision Contrast Test System, may be performed at distance or near, and consists of 5 rows of sine wave gratings with different spatial frequencies and contrasts.
The _-wave is the first large negative component of the ERG, which is followed by the _-wave which is corneal positive and usually larger in amplitutde.
The a-wave is the first large negative component of the ERG, which is followed by the b-wave, which is corneal positive and usually larger in amplitude.
The a-wave measures responses primarily from the _____________ in ____ condition.
The a-wave measures responses primarily from the photoroeceptor outer segments in dark-adapted condition.
The __________ shows downward deflection (reflecting the potential of the photoreceptors in the outer retina).
The a-wave shows downward deflection (reflecting the potential of the photoreceptors in the outer retina).
The ability to resolve or discriminate spatially visual stimuli is measured with ____________ and ______________.
The ability to resolve or discriminate spatially visual stimuli is measured with visual acuity and contrast sensitivity.
The active electrode for the VEP is placed on the ________ region.
The active electrode for the VEP is placed on the occipital region.
The amplitude of the a-wave is measured from the _______ to the ___________, while the b-wave amplitude is measured from the __________ to the _________.
The amplitude of the a-wave is measured from the baseline to the negative trough of the a-wave, while the b-wave amplitude is measured from the trough of the a-wave to the peak of the b-wave.
The area within which Ricco's law of total spatial summation holds true is called the _____________.
The area within which Ricco's law of total spatial summation holds true is called the critical area. Critical area varies with retinal location.
The_______of a sine wave grating is the mean of the peaks and troughs.
The average luminance of a sine wave grating is the mean of the peaks and the troughs.
The b-wave is due to an increase in extracellular _________ and measures the function of the _________ of the retina. It represents activity of ______ cells.
The b-wave is due to an increase in extracellular potassium and measures the function of the inner layers of the retina. It represents activity of bipolar cells.
The b-wave is lowest at _____ and highest at ______.
The b-wave is lowest at 6AM and highest at 12PM noon.
The _________ reflects the function of the inner layers retina, with major input from On Bipolar cells (and some from Muller glial cells).
The b-wave reflects the function of the inner layers of the retina, with major input from On Bipolar cells (and some from Muller glial cells).
The __________ is a prolonged positive wave of lower amplitude than the b-wave generated from the RPE in response to rods signals only.
The c-wave is a prolonged positive wave of lower amplitude than the b-wave generated from the RPE in response to rods signals only.
The _________ response of bipolar cells is directly from the photoreceptors, while the ____________ response is generated indirectly by horizontal cells.
The center response of bipolar cells is directly from the photoreceptors, while the surround response is generated indirectly by horizontal cells.
The ___________ states that the human visual system interprets information about color by processing signals in an antagonistic manner.
The color opponent process states that the human visual system interprets information about color by processing signals in an antagonistic manner.
The contrast sensitivity function (CSF) and temporal human transfer functions are ___________ functions with max sensitivity to low-mod frequency ______ Hz.
The contrast sensitivity function (CSF) and temporal human transfer functions (TMTF) are band pass functions with max sensitivity to low-modulation frequency 4-10 Hz.
The contrast sensitivity function is associated with ____________, ___________, and ____________.
The contrast sensitivity function is associated with mobility, falls, and face and sign recognition.
The cornea is electrically _________ compared to the back of the eye.
The cornea is electrically positive compared to the back of the eye.
The cornea maintains a ________ charge, while the retina is _______ charged.
The cornea maintains a positive charge, while the retina is negatively charged.
The ________ is a small negative wave which reflects the function of Off Bipolar cells.
The d wave is a small negative wave which reflects the function of Off Bipolar cells.
The dark adaptation curve of a patient with X-linked congenital stationary night blindness will lack the __________ portion.
The dark adaptation curve of a patient with X-linked congenital stationary night blindness will lack the scotopic/rod portion.
The dark adaptation curve of a rod monochromat will lack the ___________ portion.
The dark adaptation curve of a rod monochromat will lack the photopic/cone portion.
The degree of photoreceptor hyperpolarization is related to the intensity of the stimulus. Therefore, it is called a ______ potential.
The degree of photoreceptor hyperpolarization is related to the intensity of the stimulus. Therefore, it is called a graded potential.
The dendrites of bipolar cells synapse with ________ and _________, and the axons synapse with _________ and __________.
The dendrites of bipolar cells synapse with photoreceptors and horizontal cells, and the axons synapse with ganglion cells and amacrine cells.
The difference between the cone plateau and the rod plateau is the _________________.
The difference between the cone plateau and the rod plateau is the photochromatic interval.
The _______ stream to the _______ lobe processes motion, while the ________ stream to the _______ lobe processes object discrimination
The dorsal stream to the parietal lobe processes motion, while the ventral stream to the temporal lobe processes objection discrimination.
The _____________ measures the continuous resting potential across the retina.
The electro-oculogram (EOG) measures the continuous resting potential across the retina.
The entire dark adaptation curve becomes _____________ with age due to rod photoreceptor loss.
The entire dark adaptation becomes elevated with age due to rod photoreceptor loss.
The ffERG is primarily generated from the _______ retina.
The ffERG is primarily generated from the outer retina.
The ________ measures overall rod and cone generated retinal responses, provides no information as to localization of defect in the retina, and may not be affected by macula defects.
The ffERG measures overall rod and cone generated retinal responses, provides no information as to localization of the defect in the retina, and may not be affected by macula defects.
The first section of the dark adaptation curve represents the ________ threshold.
The first section of the dark adaptation curve represents the photopic/cone threshold.
The _________ sine wave has the same frequency as the square wave.
The fundamental sine wave has the same frequency as the square wave.
What is the half-life of regeneration of the cone photopigment?
The half-life of regeneration of the cone photopigment is 1.5 minutes.
What is the half-life of the rod photopigment (rhodopsin)?
The half-life of regeneration of the rod photopigment (rhodopsin) is 5 minutes.
The high frequency cut-off of the contrast sensitivity function occurs at ____ cycles per degree or 20/____ visual acuity.
The high frequency cut-off of the contrast sensitivity function occurs at 60 cycles per degree or 20/10 visual acuity.
The high resistance of the ________ prevents the summated current from passing posteriorly in an ERG.
The high resistance of the RPE prevents the summated current from passing posteriorly in an ERG.
The high-frequency cutoff for the TMTF represents the highest temporal frequency that can be resolved (flickering) at ________% modulation.
The high-frequency cutoff for the TMTF represents the highest temporal frequency that can be resolved (flickering) at 100% modulation.
The human spatial modulation transfer function is known as the ____________.
The human spatial modulation transfer function is known as the contrast sensitivity function.
The introduction of a shutter will _________ flicker.
The introduction of a shutter will reduce flicker.
The limit of movement is_______degrees per second before dynamic visual acuity is degraded due to the inability for ____________ and __________ to keep up.
The limit of movement is 60-80 degrees per second before dynamic visual acuity is degraded due to the inability of smooth pursuit eye movements and VOR to keep up.
The _________ provides trace arrays, topographic maps, and evaluates macula function and localized areas of concern.
The mfERG provides trace arrays, topographic maps, and evaluates macula function and localized areas of concern.
The ___________ sensitive system determines the threshold at any time.
The more sensitive system determines the threshold at any time.
The neurotransmitter, _________, hyperpolarizes the bipolar cells, causing them to release ________ glutamate to their connecting ganglion cells.
The neurotransmitter, GABA, hyperpolarizes the bipolar cells, causing them to release less glutamate to their connecting ganglion cells.
The opposite effects of light on the center and surround is called _________ or __________.
The opposite effects of light on the center and surround is called spatial antagonism and lateral inhibition.
Describe what the dark adaptation curve of a patient with Vitamin A deficiency might look like.
The patient with Vitamin A deficiency might have an elevated scotopic/rod portion of the dark adaptation curve (higher threshold).
The period of temporal summation for the scotopic system is ______ msec, while the period of temporal summation for the photopic system is ______ msec.
The period of temporal summation for the scotopic system is 100 msec, while the period of temporal summation for the photopic system is 10-50 msec.
The ________ ERG utilizes repetitive stimuli of high intensity flashes to measure cone activity only.
The photopic 30-Hz flicker response ERG utilizes repetitive stimuli of high intensity flashes to measure cone activity only.
The photopic a wave (ap) is ________ and occurs ______ the scotopic a wave (as).
The photopic a wave (ap) is smaller and occurs before the scotopic a wave (as).
The photopic b wave (bp) is _________ and occurs _____ the scotopic b wave (bs).
The photopic b wave (bp) if smaller and occurs before the scotopic b wave (bs).
________ measures retinal ganglion cell function/damage and occurs at about 80 to 90 msec.
The photopic negative response (PhNR) measures retinal ganglion cell function/damage and occurs at about 80 to 90 msec.
The ___________ response originates from ganglion cells, is affected in glaucoma, and may be helpful when a visual field is unreliable.
The photopic negative response, PhNR, originates from ganglion cells, is affected in glaucoma, and may be helpful when a visual field is unreliable.
The _________ ERG utilizes high intensity flashes with intense background light in a light-adapted patient to elicit smaller a and b-waves with less implicit time.
The photopic single flash ERG utilizes high intensity flashes with intense background light in a light-adapted patient to elicit smaller a- and b-waves with less implicit time.
The __________ system is more sensitive to contrast.
The photopic system is more sensitive to contrast.
The photopic system responds _______; to flickering stimuli of up to _________Hz.
The photopic system responds faster; to flickering stimuli of up to 50 Hz.
The point at which temporal frequency is so high that a flicker is no longer resolved is the __________________.
The point at which temporal frequency is so high that a flicker is no longer resolved is the critical flicker fusion frequency, CFF.
The rate of stimulus presentation may be altered in a VEP such as in the ______________ VEP.
The rate of stimulus presentation may be altered in a VEP such as in the transient vs. steady state VEP.
The ratio between the light peak and dark trough of an EOG is known as the ___________.
The ratio between the light peak and the dark trough of an EOG is known as the Arden Ratio.
The response of amacrine cells is _____ and at stimulus ______ and __________.
The response of amacrine cells is brief and at stimulus onset and offset.
The __________ ERG utilizes a brighter standard flash in the dark adapted eye to elicit both a rod and cone response.
The scotopic maximal combined response ERG utilizes a brighter standard flash in the dark adapted eye to elicit both a rod and cone response.
The ___________ ERG utilizes a bright flash to record the Ops riding on the b-wave.
The scotopic oscillatory potentials ERG utilizes a bright flash to record the Ops riding on the b-wave.
The_________ERG indicates rod function in the peripheral retina and elicits only a b-wave.
The scotopic rod ERG indicates rod function in the peripheral retina and elicits only a b-wave.
The scotopic system responds _________; to flickering stimuli of __________ Hz.
The scotopic system responds slower; to flickering stimuli of 10-15 Hz.
The second section of the dark adaptation curve begins at about __ minutes and represents the _____________ threshold.
The second section of the dark adaptation curve begins at about 12 minutes and represents the scotopic/rod threshold.
The spatial contrast sensitivity at 10 cycles per degree reflects __________ and is affected mainly by _________.
The spatial contrast sensitivity at 10 cycles per degree reflects spatial resolution VA and is affected mainly by optical defocus.
The _____________describes the amount of information transferred by the lens as function of spatial frequency.
The spatial modulation transfer function of a lens (SMTF) describes the amount of information transferred by the lens as a function of spatial frequency.
The _________ VEP uses high temporal frequency and elicits a sinusoidal waveform.
The steady state/sustained VEP uses high temporal frequency and elicits a sinusoidal waveform.
The threshold for resolution acuity is _____________.
The threshold for resolution acuity is the minimum angle of resolution (MAR).
The ________VEP uses a low temporal frequency which allow brain activity to return to baseline.
The transient VEP uses a low temporal frequency which allows brain activity to return to baseline.
The waveform of the mfERG is a ______ response and its peaks are called N1, P1, and N2.
The waveform of the mfERG is a first-order response and its peaks are called N1, P1, and N2.
There are __ types of retinal ganglion cells, which connect to _______ and _________ cells, with each type specialized for encoding a particular aspect of the visual world.
There are 18 types of retinal ganglion cells which connect to bipolar and amacrine cells, with each type specialized for encoding a particular aspect of the visual world.
Those with "on" bipolar defects will have trouble seeing at ___________ because ______ bipolar cells are all "on" type.
Those with "on" bipolar cell defects will have trouble seeing at night because rod bipolar cells are all "on" type.
___________ occurs as long as the threshold number of quanta are delivered within a critical duration.
Total temporal summation occurs as long as the threshold number of quanta are delivered within a critical duration.
True or False: Some Amacrine cells are center-surround.
True. Some amacrine cells are center-surround.
True or false: Malingering can impair VEP results.
True: Purposeful poor fixation may impair VEP results.
Under certain ________ conditions, the perception of motion is impaired.
Under certain isoluminant conditions, the perception of motion is impaired.
Under __________ conditions objects appear to move about 25% slower than under _____ conditions.
Under scotopic conditions objects appear to move about 25% slower than under photopic conditions.
Under standard parameters of dark adaptation the adapting light is _______ and the stimulus is _________.
Under standard parameters of dark adaptation the adapting light is bright white and the stimulus is dim blue.
VEP amplitude is greatest at ______ and begins to decrease at _______.
VEP amplitude is greatest at 7-8 years and begins to decrease at 28.
______ is a clinical measure of the visual pathway function used when there is unexplained vision loss.
VEP is a clinical measure of the visual pathway function used there is unexplained vision loss.
_______ is triggered by a precise and defined repetitive visual stimulus, while _____ is random relative to visual stimulus.
VEP is triggered by a precise and defined repetitive visual signal, while EEG is random relative to visual stimulus.
VEP is usually recorded from the ________ region using electrodes.
VEP is usually recorded from the occipital region using electrodes.
VEP reflects primarily activity from the ________ of the visual field only due to the uneven topographic representation of the visual field in the striate cortex.
VEP reflects primarily activity from the central 10 degrees of the visual field only due to the uneven topographic representation of the visual field in the striate cortex.
VEP waveforms are a small signal extracted from the ____________.
VEP waveforms are small signal (5uV) extracted from the electroencephalogram (EEG)
VEPs can ____________ visual acuity obtained with other methods.
VEPs can over-estimate visual acuity obtained with other methods.
Veiling glare may be measured with a __________ and degrades vision/contrast with _______.
Veiling glare may be measured with a brightness acuity tester (BAT) and degrades vision/contrast with media opacities.
_________ glare occurs when a light shining into the eye causes light scatter.
Veiling glare occurs when a light shining into the eye causes light scatter.
___________ is the process by which light when focused on the retina and absorbed by the outer segment of the photoreceptors is converted into electrical energy signals which our brain can interpret.
Visual transduction is the process by which light when focused on the retina and absorbed by the outer segment of photoreceptors is converted into electrical energy signals which our brain can interpret.
_______________ is the only electrophysiologic test that measures visual cortical activity.
Visually evoked potential (VEP) is the only electrophysiologic test that measures visual cortical activity.
Weber's Law states that ________.
Weber's Law states that the just noticeable difference is proportional to the intensity of the original stimulus.
Weber's constant for photopic vision = _____________.
Weber's constant for photopic vision = 0.015.
Weber's constant for scotopic vision = _____________.
Weber's constant for scotopic vision = 0.14.
Weber's fraction for visual contrast is written as _________________________.
Weber's fraction for visual contrast is written as Contrast= (Lmax-Lmin)/(Lmax).
______________ is most commonly used to measure visual contrast for optotypes.
Weber's fraction is most commonly used to measure visunal contrast for optotypes.
Weber's fraction/constant is _____________________.
Weber's fraction/constant, k=increment threshold/background intensity.
When __% of rhodopsin in the rod outer segment is bleached, critical numbers of sodium channels are closed and further bleaching of rhodopsin does not result in further hyperpolarization.
When 10% of rhodopsin in the rod outer segment is bleached, critical numbers of sodium channels are closed and further bleaching of rhodopsin does not result in further hyperpolarization.
With the exception of mfVEP, VEP does not _________ the lesion.
With the exception of mfVEP, VEP does not localize the lesion.
ipRGCs (intrinsically photosensitive retinal ganglion cells) contain their own photopigment, ___________, are ______________ to light, and have peak sensitivity at _______.
ipRGCs (intrinsically photosensitive retinal ganglion cells) contain their own photopigment, melanopsin, are directly responsive to light (even without rods or cones), and have peak sensitivity at 480 nm (mesopic blue light).
Multi-focal ERG measures local electrophysiological responses from different regions of the central __________ degrees of the retina, using a stimulus array of either _______ or _____ hexagons.
mfERG measures local electrophysiological responses from different regions of the central 40-50 degrees of the retina, using a stimulus array of either 61 or 103 hexagons.
