NBEO- Visual Perception (Non Big 8)

_______________ is the minimum amount of a variable that an individual can detect 50% of the time.

Threshold

As threshold increases, sensitivity ____________.

Decreases (inversely related)

What is the main method used when determining the dark adaptation of a patient?

A) Method of ascending limits

B) Method of descending limits

C) Stairstep method

D) Adjustment method

E) Method of constant stimuli

A) Method of ascending limits

What is the main method used when determining the visual acuity of a patient?

A) Method of ascending limits

B) Method of descending limits

C) Stairstep method

D) Adjustment method

E) Method of constant stimuli

B) Method of descending limits

What is the main method used when performing a Humphrey Visual field on a patient?

A) Method of ascending limits

B) Method of descending limits

C) Stairstep method

D) Adjustment method

E) Method of constant stimuli

C) Stairstep method

Is a patient with a strict or lax criteria more likely to have a higher number of false positives?

Lax criteria

Is a patient with a strict or lax criteria more likely to have a higher number of false negatives?

Strict criteria

Which of the following techniques is LEAST likely to be used clinically during an optometric exam?

A) Method of ascending limits

B) Method of Constant stimuli

C) Stairstep method

D) Method of descending limits

B) Method of Constant stimuli (takes too long)

Which of the following techniques will be negatively impacted by a patient's anticipation the MOST? (Choose 2)

A) Stairstep method

B) Method of constant stimuli

C) Method of ascending limits

D) Method of descending limits

C and D

Which visual acuity method is an example of a forced choice method?

A) Snellen acuity

B) Teller acuity

C) ETDRS

D) Landolt C

B) Teller acuity

_______________ provides a mathematical basis for determining how a patient selects the signal from the noise during a test.

Signal Detection Theory

Which of the following is considered a Type 1 error when applying Signal Transduction Theory?

A) True positive

B) False positive

C) True negative

D) False negative

B) False Positive

Which of the following is considered a Type 2 error when applying Signal Transduction Theory?

A) True positive

B) False positive

C) True negative

D) False negative

D) False negative

________________ is the probability that a test will accurately detect those patients with the disease.

Sensitivity

__________________ is the probability that the test will accurately detect those patients without the disease.

Specificity

False negative rate= 1- ______________.

A) Specificity

B) Sensitivity

B) Sensitivity

False positive rate= 1- ______________.

A) Specificity

B) Sensitivity

A) Specificity

_________________ is the probability that the patient has the disease if the test is positive.

Positive predictive value (PPV)

_________________ is the probability that the patient does not have the disease if the test is negative.

Negative predictive value (NPV)

What is plotted on the X-axis of a Receiver Operating Characteristic (ROC) curve?

A) True positives

B) False positives

C) True negative

D) False negatives

B) False positives

What is plotted on the Y-axis of a Receiver Operating Characteristic (ROC) curve?

A) True positives

B) False positives

C) True negative

D) False negatives

A) True positives

Will a patient with lax or strict criteria fall on the upper right of an ROC curve?

Lax criteria

Will a patient with lax or strict criteria fall on the bottom left of an ROC curve?

Strict criteria

Which of the following is NOT true regarding a ROC curve?

A) Strict criteria will be plotted on the lower left of the curve

B) Lax criteria will be plotted on the upper right of the curve

C) It plots the number of false positive compared to the number of hits

D) If a signal has greater detectability, there will be a flatter ROC curve due to the higher rate of hits compared to false positives

D (More curved!)

What is the unit of measurement for Radiant power?

Watts

Which of the following describes the radiant intensity per projected area of a light source and is used to describe extended sources that have an area such as a fluorescent tube of light?

A) Radiant intensity

B) Radiance

C) Irradiance

B) Radiance

Which of the following describes the radiant power in a given direction that is used to describe a point source?

A) Radiant intensity

B) Radiance

C) Irradiance

A) Radiant intensity

Which of the following describes the radiant power per unit area of surface and describes the amount of light that reaches a surface?

A) Radiant intensity

B) Radiance

C) Irradiance

C) Irradiance

What is the unit of measurement for Luminous power?

Lumens

Is Radiometry or Photometry more associated with how we perceive light?

Photometry

What is the peak sensitivity of the photopic luminous efficiency function?

555 nm

What is the peak sensitivity of the scotopic luminous efficiency function?

507 nm

For the photopic system, at 555 nm there is approximately ____________ lumens per watt according the luminous efficiency function.

680 lumens per watt

Which of the following is the luminous intensity per projected area of a light source and can be recorded in nits or Foot-Lamberts?

A) Luminous intensity

B) Luminance

C) Illuminance

B) Luminance

Which of the following deals with point sources and is recorded in candelas?

A) Luminous intensity

B) Luminance

C) Illuminance

A) Luminous intensity

Which of the following is measured in Lux or Foot-candles?

A) Luminous intensity

B) Luminance

C) Illuminance

C) Illuminance

For the scotopic system, the peak sensitivity occurs at 507 nm which corresponds to ____________ lumens/watt at that point of the luminous efficiency function.

1700 lumens/watt

Which type of filter allows for a small range of wavelengths to pass through and is specified by its location of peak wavelength as well as the half-height bandwidth?

A) Narrow band filter

B) Interference filters

C) Broad band filter

D) Long-pass filter

A) Narrow band filter

Which of the following is NOT true regarding an interference filter?

A) It is highly sensitive

B) It is considered to have a high half-height bandwidth

C) It essentially only transmits a single wavelength

D) It is considered to have a low half-height bandwidth

B

Which type of filter essentially only transmits a single wavelength?

A) Narrow band filter

B) Interference filters

C) Broad band filter

D) Long-pass filter

B) Interference fitlers

Which type of filter essentially only transmits long wavelengths which results in altered color perception?

A) Narrow band filter

B) Interference filters

C) Broad band filter

D) Long-pass filter

D) Long-pass filter

Which type of filter transmits all wavelengths equally which minimizes color distortion?

A) Narrow band filter

B) Neutral density filter

C) Broad band filter

D) Long-pass filter

B) Neutral density filter

According to Pulfrich's phenomenon, if a neutral density filter is placed over a patient's left eye, will the pendulum appear to move clockwise or counterclockwise?

Left eye= Clockwise

According to Pulfrich's phenomenon, if a neutral density filter is placed over a patient's right eye, will the pendulum appear to move clockwise or counterclockwise?

Right eye= Counterclockwise

A surface that shows the same luminance from every viewing angle is known as a ______________ surface.

Lambert surface

A surface that unequally scatters light in all directions is known as a ____________ surface.

Specular surface

Is a paper with matte finish more representative of a Lambert Surface or Specular Surface?

Lambert surface

Is a shiny piece of silver more representative of a Lambert Surface or Specular Surface?

Specular Surface

The general relationship between luminance and illumination for a Lambert surface is _____________.

A) Inversely related

B) Linear

C) x^2

D) x^3

B) Linear

What is the formula for Retinal Illumination?

T=LA

T= Trolands

L= Luminance

A= Area of the pupil

What is the unit of measurement for Retinal Illumination?

Trolands

How do we find the area of the pupil given the radius of the pupil? (We need to perform this calculation when determining retinal illumination)

A=πr^2

Both photopic and scotopic systems are active under ____________ conditions which are characterized by dimly lit setting will small amounts of bright light such as during sunset.

Mesopic conditions

Which of the following is poor in Photopic vision?

A) Color vision

B) Visual acuity

C) Facial recognition

D) Sensitivity

D) Sensitivity

The ________________ states that a photopigment responds to the absorption of a photon in a manner that is completely independent of the wavelength of the photon. As a result, all information about the wavelength of the photon is lost.

Principle of Univariance

How is color vision determined?

A) The relative responses of photoreceptors based on the number of photons absorbed

B) The relative responses of photoreceptors based on the wavelengths of the photons absorbed

C) The total number of photons absorbed by a single photoreceptor

D) The wavelength of a photon absorbed by a single photoreceptor

A) The relative responses of photoreceptors based on the number of photons absorbed

Which wavelength is the point of equal sensitivity of the photopic and scotopic systems?

650 nm

The difference between the sensitivities of the scotopic and photopic systems at a given wavelength is known as the _____________.

Photochromatic interval

What is the photochromatic interval value at 650 nm?

A) 1

B) 5

C) 10

D) 0

D) 0 (point of equal sensitivity)

As the illumination increases, do longer or shorter wavelengths appear brighter?

longer wavelengths (Ex: red)

As the illumination increases, longer wavelengths appear brighter which is known as the ______________ shift.

Purkinje shift

The shift from the photopic to scotopic system appears as a blip in the dark adaptation curve and is known as the _______________.

Rod-cone break

The rod-cone break is absent from a dark adaptation curve at ___________ nm because the photopic and scotopic systems are equally sensitive to this wavelength.

650 nm

What does the Dowling-Rushton equation describe?

A) Contrast sensitivity

B) Spatial frequency

C) Dark adaptation

D) Retinal illuminance

C) Dark adaptation

Do rod photopigments or cone photopigments regenerate first during dark adaptation?

Cone photopigments

The 1/2 life for cone photopigment regeneration is approximately ____________ minutes.

1.5 minutes

The 1/2 life for the regeneration of rod photopigment (rhodopsin) is approximately ____________ minutes.

5 minutes

Is cone adaptation or rod adaptation the initial (upper left) portion of a standard dark adaptation curve?

Cone adaptation

How long does it take for a dark adaptation curve to reach the rod plateau for a typical patient?

A) 1.5 minutes

B) 5 minutes

C) 12 minutes

D) 35 minutes

D) 35 minutes

Are rod or cone photoreceptors more sensitive during the initial phase of a dark adaptation curve?

Cone photoreceptors

Do rod or cone photoreceptors have a higher threshold during the initial phase of a dark adaptation curve?

Rod photoreceptors (higher threshold= lower sensitivity)

What is DeVries-Rose Law used for?

A) Dark adaptation

B) Light adaptation

C) Color vision

D) Contrast sensitivity

B) Light adaptation

Which of the following equations are implemented throughout light adaptation? (Choose 2)

A) DeVries-Rose Law

B) Dowling-Rushton Law

C) Hering's Law

D) Weber's Law

A and D

Region 2 on a light adaptation curve in which the slope is 1/2 is the area of the curve that can be quantified by which law?

DeVries-Rose Law (Square Root Law)

Region 3 of a light adaptation curve is when the change in intensity/ the change in background intensity if constant and the slope of the curve=1. This area of the curve can be quantified by which law?

Weber's Law

Which law computes the Just Noticeable difference on a light adaptation curve?

Weber's Law

The difference between the intensity of the just perceivable spot of light compared to the intensity of the background is known as the _____________.

Just noticeable difference

Is the Scotopic system or Photopic system more sensitive to contrast according to Weber's Fraction?

Photopic system is more sensitive

Photopic= .015

Scotopic= .14

Does the scotopic or photopic system have greater sensitivity?

Scotopic

Which law describes the relationship between the intensity and the area of a stimulus that is below the threshold for spatial summation? It states the total number of photons for a stimulus below the critical diameter is constant.

Rico's law

Is the critical diameter of scotopic or photopic system larger during spatial summation?

Scotopic system

The critical duration for the scotopic system for temporal summation is approximately ______________ ms.

100 ms

The critical duration for the photopic system for temporal summation is approximately _____________ ms.

10 ms

As illumination decreases, does shorter wavelength or longer wavelengths become brighter?

Shorter wavelengths

Does the scotopic or photopic system have better temporal summation?

Scotopic

Does the scotopic or photopic system have better temporal resolution?

Photopic

Does the scotopic or photopic system have better spatial resolution?

Photopic

Does the scotopic or photopic system have better spatial summation?

Scotopic

What is the constant for both Bloch's Law and Ricco's Law?

A) Stimulus Area

B) Time duration

C) Threshold visibility

C) Threshold visibility

Is Bloch's law related to spatial or temporal summation?

Temporal summation

Is Ricco's law related to spatial or temporal summation?

Spatial summation

Cone photoreceptors are most sensitive to rays of light that strike orthogonal to the surface which is known as the _______________ effect.

Stiles-Crawford Effect

Cones photoreceptors are most sensitive to rays of light that strike __________ to the surface.

A) Parallel

B) Perpendicular

C) Orthogonal

D) Tangential

C) Orthogonal

What is the peak photoreceptor absorption spectra of a S cone?

426 nm

What is the peak photoreceptor absorption spectra of a M cone?

530 nm

What is the peak photoreceptor absorption spectra of a L cone?

557 nm

What is the peak photoreceptor absorption spectra of a rod?

507 nm

What is the photopigment associated with a S cone?

Cyanolabe

What is the photopigment associated with a M cone?

Chlorolabe

What is the photopigment associated with a L cone?

Erythrolabe