visual perception

Question 1

what pathway is most likely to get damaged first in glaucoma

Answer 1

magnocellular

Question 2

scotopic vision is characterized by

Answer 2

high sensitivity rot dim lights

Question 3

how will a patients perception of the brightness of an image be affected inhere pupil is moved off center but remains the same diameter

Answer 3

decreased

Question 4

eye movements that occur during fixation prevent which of the following effects

Answer 4

troxler effect

Question 5

mango cells

Answer 5

involved with motion have the following characterizes

• function as part of the “where” system that detects and alerts the visual system to objects
• located in the peripheral retina
• have large perceptive fields to increase sensitivity to large stimuli with low spatial frequencies and high temporal frequencies
• they quickly transmit signals to area MT in the visual cortex

Question 6

Parvo cells

Answer 6

are involved with color perception and have the following characteristics

• function as part of the “what” system that resolves fine details of objects
• primarily located in the fovea
• have small receptive fields and are most sensitivity to low temporal frequencies and high spatial frequencies
• slower response time compared ro mango cells

Question 7

glaucoma and magnocellualr

Answer 7

results in decreased ability to process moving stimuli. Frequency doubling perimetry Is a peripheral vision test that selectively target he magno cells and thus theoretically detect early glaucoma damage

Question 8

scotopic vision

Answer 8

occurs in dim lighting conditions and is primarily mediated by rod PRs. As a result, it is characterized by poor color discrimination and visual acuity, but high spatial summation. The scotopic system is maximally sensitive to light with a wavelength of 507nm

Question 9

photopic vision

Answer 9

occurs in bright conditions and is primarily mediated cone PR. As a result, it is characterized by excellent VA, contrast sensitivity, and color discrimination, but low temporal summation and poor sensitivity to low light level. The scotopic system is maximally sensitive to light with a wavelength to 555nm

Question 10

stiles-crawford effect

Answer 10

states that light that strikes cones perpendicular will appear brighter than light that strikes the cones ar a non orthogonal angle. Thus, an off center pupil will cause light rays to hit the cones at angles other than 90 degrees, resulting in the light appearing dimmer

Question 11

troxler effect

Answer 11

describes the fading of peripheral images when the eye is fixated on a central object due to lateral inhibition in the retina. The eyes are constantly moving during fixation in order to prevent the imaging from disappearing

Question 12

Broca-Sulzer effect

Answer 12

light flashes above threshold appear brightest when they last approximately 50-100msec. Longer or shorter flashes flight with the same intensity will appear dimmer

Question 13

Brucke-Bartley effect

Answer 13

flickering light appears brighter than a steady light of the same average luminance

Question 14

Masking

Answer 14

one stimulus (the mask) decreases the visibility of another stimulus (the target)