Vision Flashcards
Identification of misalignment between 2 lines or gratings is called
Vernier acuity
Neonatal VA is approx
<6.60
Neural pathways to the visual cortex continue to develop to age ?
8
What is the definition of angle alpha
angle between optical and visual axes
describes the offset of the eye relative to the optical axis
How mant degrees horizontally is angle alpha
5.2
What is definiton of angle kappa
angle between the pupillary axis and visual axis
How is angle kappa measure
angle between centre of the pupil and the light reflex
How much is angle kappa horizontally
2.6 degrees
If you had to draw the visual axis what would it be
line to the fovea
If you had to draw the pupillary axis what would it be
line through centre of pupil
If you had to draw the optical axis what would it be
line through geometric centre of lens
density of cone receptors is highest where in the retina
fovea
what is the formular for snellen VA
1/min angle of resoluton
the whole letter on snellen chart subtends __ arcminutes
5
the gap in C or E on snellen chart subtends _ arcminutes
1
HOw many letters per line in logMAR
5
How many m away for logMAR chart
4m
what phenomenon is reduced in logMAR
crowding
Which 3 VA testings can be used in children
Teller Keeler Cardiff
What VA testing for 2+
Kay picture cared
Which 3 VA testing used for 3+
Sheridan Gardiner, Sonksn Silber, KeelerlogMAR
What can be used for objective measure of VA
Visual evoked potentials
What type of VEP used for infants/uncooperative patients
flash VEP
What do Pelli Robson and Vistech wall charts measure
contrast sensitivity
Fovea has poor sensitivity for which colour light
blue light
How many Hz is optimum flicker
10Hz
Dark adaptation takes how long
20 mins
Following dark adaptation, which is more sensitiy, rods or cones
rods
What phenomemen can happen in unilateral optic neuritis where there is an illusion of abnormal motion
Pulfirch phenomenon
What is the total amount of light emitted called
luminous flux
Luminous flux is measured in
lumens
Amount of light per solid anlge is called
Luminous intensity
Luminous intesnity is measure in
candelas
Illumination/illuminace is described as
amount of light arriving at a surface
Illumination/illuminance is meausre in
lux
What is the formular for luminance
light emitted/light reflected from surface
What is luminance measured in
lamberts
S wave cones sensitivity to what colour and wavelength
blue - 445
M wave cones sensitivity to what colour and wavelength
green 545
L wave cones sensitivity to what colour and wavelength
red 570
peak sensitivity for rod cones
500nm
red green colour defect are from which chromosome abnormality
X
in dark adapted conditions which wavelength has peak luminosity
blue green 500nm
in photopic conditions which wavelength has peak luminosity
yellow green 555nm
Ishihara detects what colour vision defect
red/green
What is the most comprehensive colour vision test
Farnswork Munsell 100 hue test
What is the colour test designed for children
Lanthony New Colour test
macular disorder give rise to what colour vision defects
blue yello
optic neuropathies give rise to what colour vision defects
red green
Name 3 tests for steropsis
Frisby, Lang, TNO
