Visual Acuity Flashcards

1
Q

definition of visual acuity

A

the ability of the visual system to resolve fine detail

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2
Q

what is spatial visual acuity?

A

the finest spatial detail that can be detected, discriminated, or resolved

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3
Q

detection acuity means the

A

angular size of the smallest visible target

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4
Q

OD (oculus dexter) = ___ eye

A

right

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5
Q

OS (oculus sinister) = ___ eye

A

left

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6
Q

OU (oculus uterque) = ____ eye

A

both eyes

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7
Q

pinholes can reduce what things?

A
  • reduce effective pupil size
  • reduce refractive blur
  • reduce illuminance of the retinal image
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8
Q

pinholes can increase what?

A

increase the depth of field/depth of focus

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9
Q

what are pinholes used for?

A

to help determine if the reduction in VA is due to uncorrected refractive error or something else

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10
Q

PHNI stands for what? what could this be due to?

A

pinhole no improvement

-could be non-refractive: ocular disease, amblyopia

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11
Q

what is the “entering VA”?

A

first test performed at the start of almost every eye exam (medical-legal issue)

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12
Q

snellen chart’s spacing and progression are: regular or irregular?

A

irregular

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13
Q

in the snellen notation fraction, the numerator is the

A

testing distance

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14
Q

in the snellen notation fraction, the denominator is the

A

letter size

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15
Q

definition of “letter size” for senile chart

A

distance at which the overall letter height subtends 5 minutes of arc

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