Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NBEO I > Optics/Specs/CLs > Flashcards

Optics/Specs/CLs Flashcards

1
Q

Another name for neutralizing power

A

Front vertex power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Approximate power of lens at birth

A

45 D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Basic unit to measure retinal illumination

A

Trolands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What has a unit of lumens

A

Luminous power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which purkinje image is the largest? The smallest?

A

3 (optoprep)
4 is the smallest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What type of higher order aberration is most common after a decentered keratorefractive ablation?

A

Coma

  • 3rd order aberration
    (When peripheral light rays from one side of cornea are focused in front of the retina while peripheral rays from the other side of the cornea are focused behind the retina)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What has a higher Abbe value: CR-39 or Trivex?

A

CR-39
(58 while Trivex is 30)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which chromosome contains M and L cones? S cones? rods?

A

M and L - X chromosome
S - chromosome 7
Rods - chromosome 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Unit of radiant power

A

Watts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Radiometry vs Photometry

A

Radiometry - actual physical energy produced by EMR

Photometry - how the visual system responds to EMR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which type of color vision deficiency is the Ishihara plates test specifically designed for

A

Red-green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What age does pupillary light reaction occur? Lid closure response to bright light?

A

Both at 30 weeks gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What notation is used to record vision in low vision patients

A

Metric notation
(A 1 M letter subtends 5 min of arc at 1 meter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If a patient were able to read the 3 M line at 25 cm, what is their VA in metric notation?

A

0.25/3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Taller patients generally need their near segments set …

A

Lower
(They move their eyes lower when reading)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which condition would have the most decrease in vision as illumination increases?
A. Macular degeneration
B. Congenital achromatopsia
C. End stage glaucoma
D. Cataracts

A

B
(Congenital achromatopsia means that patients primarily rely on rods for vision. Rods are readily saturated at LOW levels of light so an increase in brightness will decrease their function)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Average refractive error for following age ranges:
- premature infants
- full term infants
- one year olds
- three year olds

A
  • premature -> -0.50
  • full term -> +2.00
  • one years -> +1.00
  • three years -> +0.95
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the secondary action of the superior rectus?

A

Intorsion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Unit for luminance

A

Foot-lamberts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Unit for illuminance

A

Foot-candles

(Candles illuminate the space)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

An emmetropic patient has an amp of accommodation of 3 D. What power reading glasses should give a comfortable working distance of 20 cm?

A

3.5 D

(1/2 of the patient’s total accommodation should be held in reserve. 3 x 1/2 = 1.5
Working distance of 20 cm = 5 D
5 D - 1.5 D = 3.5 D)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does a keratometer directly measure?

A

Reflecting power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Will a 510 nm light or a 620 nm light appear brighter to you under dim illumination?

A

510 nm
(bc rods are most sensitive at around 507nm in dim illumination)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which monocular depth cue explains why closer objects appear to move faster than distant objects?

A

motion parallax

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which tint for sunglasses will work best for a rod monochromat?

A

Red tint

(bc red has the least energy so it will saturate the rods least)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How does the potential acuity meter work? What is it used for? What other test is it similar to?

A

projects a Snellen chart through a tiny aperture ; used to assess BCVA if cataract surgery is performed ; similar to laser interferometry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What angle is this

A

Frontal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is a treatment option for patients intolerant to atropine/patching

A

Bangerter foil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What does a radiuscope measure

A

base curve of contact lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

A contact lens that moves too much is said to be too…

A

flat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Formula for angular magnification

A

D/4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

A low vision patient needs a +10 D add for reading. What type of prism would you build into the specs?

A

24 BI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Ideal pinhole size

A

1.2 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

ANSI standards

A

+/- 6.50 sphere power allowed +/-0.13 D
>6.50 D the tolerance is 2%
Cyl power:
- 0.25 cyl -> 14*
- 0.50 cyl -> 7*
- 0.75 cyl -> 5*
- 1.00-1.50 -> 3*
- 1.75+ cyl -> 2*

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is typically modified in high plus readers to assist in potential diplopia

A

decentering the optical centers nasally to induce BI prism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

The classic waterfall illusion is an example of which visual phenomenon?

A

motion after-effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the neutral point of a protanope

A

492

(so use this wavelength and another one to distinguish if a person is a protanope)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the most common fit for a hard contact lens

A

lid attached (lens fits under the upper eyelid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Which telescope produces an upright image: Keplerian or Galilean? Which is shorter in length?

A

Galilean; Galilean

40
Q

What axis is the astigmatism in pellucid marginal degeneration the steepest

A

180

41
Q

What is the most common cleaner used to clean hydrogel lenses

A

Surfactant

(enzymatic ones are only used a few times a month to remove protein buildup)

42
Q

3 and 9 staining is typically seen in … and chronic staining may form …

A

low-riding GP lenses (tight fitting); dellen

43
Q

What is the wavelength of blue light

A

450-495

44
Q

What is a form of backward masking

A

Metacontrast

45
Q

What is metacontrast

A

present target first and then the mask, in which they are presented adjacent to each other

46
Q

Which notation has a font that is based on the standard Times Roman numeral font

A

N notation

47
Q

Hering’s law applies to muscles in the same or both eyes?

A

both

48
Q

What is the phenomenon called when patients are unaware they have a central visual field deficit

A

perceptual completion

49
Q

What is the most accurate method of classifying congenital red-green color deficiencies

A

anomaloscope

50
Q

Which telescope is considered shorter and lighter?

A

Galilean

51
Q

What type of aberration accounts for the pincushion optical effect of high powered plus lenses

A

Distortion

52
Q

Give examples of second order aberration

A

Myopia, hyperopia and astigmatism

53
Q

In order for a person to see their entire reflection, a plane mirror must be..

A

half as tall as the person

54
Q

What aberration occurs as a result of variation in magnification across the entrance pupil from off-axis point sources

A

coma

  • the rays that pass through the outer margins of the lens focus at different distances from the optical axis as compared to the rays that pass through the center of the lens
55
Q

What can cause radial astigatism

A

an irregularly shaped cornea

56
Q

During retinoscopy, what reflex (narrow or broad; fast or slow) is indicative of a highly myopic prescription?

A

narrow, slow

(as one approaches neutrality, the reflex becomes wider and faster)

57
Q

For a real object, incident (object) rays are…

A

divergent (bc the object is located to the left of the optical system)

58
Q

For a real image, emergent (image) rays are…

A

convergent (bc the image exists to the right of the optical system)

59
Q

During retinoscopy, against motion would be observed in which of the following scenarios?
A. far point is located behind the retinoscope
B. far point is located behind the patient’s eye
C. far point is located between the retinoscope and patient’s eye
D. far point is located at the retinoscope aperture

A

C (between the retinoscope and patient’s eye)

60
Q

While performing retinoscopy, how does the resultant reflex change as you approach neutrality?

A

The reflex becomes brighter and wider (broader)

61
Q

With respect to thick lenses, all refraction is assumed to take place at which points?

A

Principal

62
Q

With a +1.00 D tentative add in place, you measure NRA +1.50 and PRA -0.50. What should the final add be?

A

+1.50

(you take the average of your NRA/PRA findings and add it to the add)

63
Q

How many reflecting surfaces does the Gullstrand #1 eye possess?

A

6 (anterior/posterior cornea; anterior/posterior lenticular nucleus; anterior/posterior lenticular cortex)

64
Q

How many reflecting surfaces does the Gullstrand #2 eye possess?

A

3 – this is the simplified eye model. the 3 surfaces are the cornea, the front surface of the lens and the back surface of the lens

65
Q

How many refracting surfaces does the reduced eye have

A

1

66
Q

Which of the four Purkinje images is a real image? Which is the only inverted image?

A

4; 4

67
Q

An incident ray of light on a flat mirror has an angle of 65 degrees from the normal; what is the angle of the reflected ray measured from the normal?

A

65 (law of specular reflection states that angle of incidence = angle of reflection)

68
Q

What is the critical angle

A

angle of incidence at which the angle of reflection is parallel to the surface (where refracted angle is 90°)

69
Q

What is the entrance pupil of an optical system

A

image of aperture stop through all preceding lenses

70
Q

What is the exit pupil of an optical system

A

image of aperture stop through all following lenses

71
Q

Which requires an add: a hand or a stand magnifier?

A

Stand

72
Q

The general pantoscopic tilt is ___ degrees

A

10

73
Q

Every two degrees of pantoscopic tilt changes the optical center by …

A

One millimeter

74
Q

A patient is able to read a letter that subtends 15 minutes of arc at 6 meters. At what M unit is the patient able to read?

A

0.5 M

(15 minutes / 6 meters = 2.5 minutes / 1 meter)
*letters subtend 1 meter at 5 minutes of arc

75
Q

What maximum percent of transmittance must lenses have to be classified as true sunglasses?

A

67% (minimum 33% absorption)

76
Q

Formula for M notation to Snellen

A

(Test distance in meters) / M = (20) / x

77
Q

You are told that a patient can read 3 M at 30 cm. To what visual acuity does this correspond?

A

0.3 / 3 = 20 / x
x = 200

So 20/200

78
Q

What phenomenon is used to make a holograph?

A

Scattering

79
Q

What phenomenon is used to make a hologram?

A

Diffraction

80
Q

What phenomenon forms a rainbow

A

Dispersion

81
Q

What is dispersion

A

The separation of light into colors via a prism

82
Q

What is the most common color vision deficiency

A

Deuteranomaly

83
Q

What is the magnification of the retina of an emmetrope during indirect ophthalmoscopy using a 20 diopter handheld lens?

A

3x

(60/4 = 15x ; 20/4 = 5x —> 15/5 = 3x)

84
Q

What is a type of forward masking?

A

Paracontrast
(The targets needs to be spatially adjacent to each other)

85
Q

Which type of masking involves presenting the mask first and then the target

A

Forward masking

86
Q

Allen vs Teller cards

A

Teller cards are used for nonverbal speaking children (infants and <3)

Allen cards are for those who know pictures (poor with letters) (2-5 years old)

87
Q

Longitudinal vs Lateral chromatic aberration

A

Longitudinal - caused by straight incident light

Lateral - caused by oblique incident light

88
Q

What device is used to verify the power of a contact lens
A. Lensometer
B. Keratometer
C. Radiuscope
D. Phoropter

A

Lensometer

89
Q

Where should the top of a bifocal segment be placed

A

Lower eyelid margin

90
Q

Where should the segment height of PALs be measured

A

Center of pupil

91
Q

Where should the segment height of trifocals be measured

A

Lower edge of pupil

92
Q

When is the vision clear in a contact lens that is too steep

A

Immediately after a blink

93
Q

Refraction yields a spec rx of -2+1x90. K readings are 46.00@90 and 48.00@180. What is the lenticular astigmatism?

A

+3.00x90

94
Q

What conditions cause photochromic lenses to darken?

A

cooler temperatures and brighter days

95
Q

Pupils under what size are prone to diffraction issues. What light do small pupils diffract the most?

A

under 2.5mm

red (longer wavelengths are diffracted more)

NBEO I (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions