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Part 1 - NBEO Prep > Ametropia/Optics/ Accommodation/Vergence/Oculomotor/Low Vision/Amblyopia/Strabismus/Color Vision/Visual Human Development > Flashcards

Ametropia/Optics/ Accommodation/Vergence/Oculomotor/Low Vision/Amblyopia/Strabismus/Color Vision/Visual Human Development Flashcards

Please note, there is information left out based on my own personal knowledge.

1
Q

BIO vs. DO, what is the difference in between the two for field of view, depth of focus, magnification and image?

A 
BIO will have:
Larger FOV
Larger Depth of focus
Smaller magnification
Inverted image
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2
Q

What is the item that moves in a lensometer? What is the formula for lensometry?

A

Target moves.

x = f^2 (F)
Note: all must be in meters.

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3
Q

Your trying hand neutralization and notice with motion. What type of lens?

A

Minus

Note: Against motion is a plus lens

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4
Q

What does the Cornea mimic?

a. Concave lens
b. Convex lens
c. Concave mirror
d. Convex mirror

A

d. Convex mirror

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5
Q

Lens clock formula?

A

F = (index of lens - 1)/(index of lens clock calibration) x F based on lens clock finding

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6
Q

Tolerance perimeter for lens thickness?

A

+/- 0.3mm

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7
Q

Tolerance for warpage?

A

1.00D

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8
Q

What is the BC tolerance?

A

+/- 0.75D

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9
Q

What is the impact resistance based on ANSI Z80.1?

A

5/8 steel ball from 50in

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10
Q

What does the “H” marking mean on safety eyewear?

A

Smaller head

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11
Q

What is the symbol for impact rating?

A

”+”

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12
Q

Where is the base curve located on a lens?

A

Front

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13
Q

Lens thickness formula

A

F= (2(ns-n1)s)/h^2

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14
Q

Minimum Blank Size

A

M=ED+2(d)+2mm

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15
Q

If the seg appears too high, what should be done to the pantoscopic tilt?

A

Increased

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16
Q

What are the index of refraction and abbe value for CR-39, Polycarbonate, High Index and Trivex?

A

CR 39 - 1.498 and 58
Poly - 1.586 and 30
H.I. - 1.54 to 1.66 and 32 to 47
Trivex - 1.53 and 43 to 45

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17
Q

Which type of rays bend the most in Spherical Abberations?

A

Marginal

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18
Q

Which type of rays are bent the most in chromatic abberations?

A

<300nm (Blue)

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19
Q

What is the best way to get rid of Chromatic Abberations?

A

Achromatic Doublet

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20
Q

Unit of prism power formula

A

Prism = y (shifting of light) /x (wall to prism)

Note: y must be in cm and x will be in m

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21
Q

Apical angle formula?

A

d=A(n-1)

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22
Q

Prism thickness formula

A

Prism = (100g(n-1))/l

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23
Q

Prentice rule

A

Prism = dF

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24
Q

Spectacle magnification formula

A

Shape factor vs Power factor

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25
Q

What is the shape factor formula?

A

SF = (1)/1-(t/n)Front surface power

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26
Q

What is the power factor formula?

A

PF = (1)/1-hF

Note: F is the back vertex power of the lens

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27
Q

What are the trends when increasing h, t, base curve and n in Plus lenses?

A

Increase SM with an increase in h, t, base curve BUT a decrease in SM with an increase in n’

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28
Q

What are the trends when increasing h, t and n in minus lenses?

A

Decrease in SM BUT an increase in SM when t is increased.

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29
Q

Axial ametropes are best corrected with?

A

Glasses ….look into Knapp’s law for further information

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30
Q

Refractive ametropes are best corrected with?

A

CTL’s

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31
Q

Regarding the retinal images size, put in from largest to smallest image size based on AXIAL length?

A

Myope>Emmetropic>Hyperopic

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32
Q

Regarding the retinal images size, put in from largest to smallest image size based on uncorrected refractive ametropes?

A

All retinal images are the same

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33
Q

Which has a larger retinal image size: a spectacle corrected refractive hyperope or a spectacle corrected refractive myope?

A

Spectacle corrected refractive hyperope

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34
Q

What is the formula for Reflectance?

A

R= ((n2-n1)^2)/((n2+n1)^2)

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35
Q

Contact lens formula?

A

Fv = F2 + (F1)/1-(t/n)F1

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36
Q

How much is there internal astigmatism?

A

-0.50 x 090

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37
Q

For 0.4mm in OZD change, how much should the BC change?

A

0.25D

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38
Q

Normally, water will carry oxygen to a high concentration, but why is that the opposite for SiHy lenses?

A

Silicone carries the oxygen faster than water.

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39
Q

Which refractive error has to accommodate more in Contact lenses?

A

Myopes

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40
Q

In low vision, what term describes the change in distance for magnification change?

A

RDM

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41
Q

Which type of magnifier requires no Add?

A

Hand magnifier

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42
Q

Formula for tube length?

A

d = fobj + foc

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43
Q

Magnification of telescopes formula?

A

M = -Foc/Fobj or M = dent/dex

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44
Q

What is the final image produced by a Kaplerian telescope?

A

Inverted and Magnified

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45
Q

Where is the exit pupil located in a kaplerian telescope?

A

Outside telescope, thus producing a DIM but large field of view.

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46
Q

What is the final image produced in a Galilean telescope?

A

Upright and Magnified

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47
Q

Where is the exit pupil in a Galilean telescope?

A

Inside the telescope, thus producing a small field of view but brighter image.

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48
Q

Due to limitation of length in a Galilean telescope, What is the maximum magnification possible to achieve?

A

4x

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49
Q

What are 2 solutions or ways to improve to view an object at near with a telemicroscope?

A

Increase tube length and/or add a reading cap

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50
Q

What type of telescope is excellent for increasing field of view for patients with Glaucoma or RP?

A

Reverse telescope

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51
Q

What is considered to be legally blind?

A

20/100 in the better seeing eye or VF diameter is 20 degrees or less in the better seeing eye.

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52
Q

What is considered severe low vision loss?

A

20/200 to 20/400

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53
Q

Low vision pts with a central scotoma will have what type of viewing?

A

Eccentric viewing

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54
Q

Formula for light house method?

A

Working distance x 2.5D

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55
Q

What type of filters are used to decrease glare?

A

Neutral Density filter & Blue blocker tint

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56
Q

Where is the far point of a hyperope?

A

Behind the retina

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57
Q

What is absolute hyperopia?

A

Hyoperopia is too large to be neutralized by accommodation.

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58
Q

What is the formula for measuring acuity from Allen vision test to Snellen?

A

x/30

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59
Q

What is static retinopathy?

A

Retinopathy behind a phoropter

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60
Q

Mneumonic for Duochrome testing?

A

RAM GAP

Red: Add minus
Green: Add plus

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61
Q

3 reasons to do cycloplegic refraction?

A
  1. Child with Strab
  2. Significant Esophoria
  3. Young adult complaining of headaches but no correction of hyperopia
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62
Q

What is the percentage of a person using their accommodative ability?

A

50%

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63
Q

An aphakic pt will display a ring scotoma, which appears and re-appears. What is this phenomenom called?

A

Jack in the box effect or Jumping effect

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64
Q

What is equally mixed astigmatism?

A

A special case of mixed astigmatism where the circle of least confusion falls on the retina.

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65
Q

Where is the major meridian for “WTR”?

A

Vertical “90 +/-30 degrees”

Note: Don’t get confused with a SRx. If the SRx notes a +3.00 -1.00 x 090; then this would be considered a vertical axis (Not meridian) thus this SRx would be considered a “ATR”

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66
Q

What is the definition of Absolute Hyperopia?

A

Cannot overcome with accommodation

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67
Q

Where is the farpoint of an hyperopic pt?

A

Behind the Retina

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68
Q

What is the working distance when checking Interpupillary distance?

A

30 cm

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69
Q

How to convert Allen Vision test to Snellen?

A

x/30

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70
Q

How to convert to convert snellen to MAR?

A

20/x = MAR

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71
Q

What is the Corneal thickness?

A

550um

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72
Q

What would be axis when confirming with Stenopaic Slit?

A

Parallel to the actual axis point

Ex. If you get -0.50 @ 180 (with the slit on the 180 meridian) and -1.50 @090 (with the slit on the 090 meridian); the SRx will be -0.50 -1.50 x 180.

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73
Q

When considering a cycloplegic, either for Latent Hyperopia or any eye turn, when should you prescribe the full SRx?

A

Any eyeturn. Never give the full latent hyperopic patient, approx. 1/2 should be given.

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74
Q

What is the JND for a pt with VA of 20/150?

A

+0.75 to -0.75

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75
Q

In directly, what fusional vergence are you testing when conducting NRA?

A

PFV (Positive Fusional Vergence)

Think about it. If you give + lens (NRA testing) you are relaxing accommodation, thus you require the eyes to converge (BO) more, hence causing PFV.

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76
Q

Which refractive product is the best option for children with Aphakia?

A

RGP

The reason for this is due to the development of the eye while keeping a healthy a viable option for tear exchange vs. SiHy lenses.

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77
Q

Doing Alternating cover test, pt’s eye moves outwards. What is the condition and which direction of the cover paddle will move based on the pt’s presspective?

A

Esophoria and Opposite direction

Note: Exophoric pt’s will notice the same direction as the cover paddle.

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78
Q

Fixation disparity curve, which will the shift of the curve be if a pt becomes more esophoric?

A

Up and to the Right.

Exophoric are down to the left and Normal are diagonal straight through the center going from top left to bottom right.

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79
Q

What are the 2 best ways (based on literature) to measure Anisokonia?

A

1) The Space Eikonometric method is based on binocular space perception.
2) The Direct Comparison method is based on directly comparing perceived image sizes between the two eyes.

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80
Q

What type of Ellipsoid is the Cornea prolate or oblate?

A

Prolate; means flattening out to the periphery.

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81
Q

What is the peak wavelengtgh for the Photopic system?

A

555 nm

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82
Q

What is the peak wavelength for the Scotopic system?

A

505 nm

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83
Q

Based on visual axis, where is the fovea placed accordingly to the ON?

A

Infero Temporal

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84
Q

What is the term when PR’s are shifted according to light?

A

Stiles-Crawford

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85
Q

What are the 3 tests for visual spatial dysfunction and what do they test specifically?

A

1) Piaget test (Laterality)
2) Jordan test (Directionality)
3) Standing Angels in the Snow (Bilateral Integration)

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86
Q

What is Maxwell’s Spot?

A

Central vision testing; red spot detected away from the fovea

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87
Q

What is Haidinger’s brush?

A

Central vision testing; using birefringence testing and you are looking for where Haidinger’s brush sits on the retina.

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88
Q

What are Moore’s lighting streaks associated with?

A

Retinal tear or Retinal detachment

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89
Q

What are blue arcs of the Retina?

A

Physiological blind spot; Dim light in a dark room.

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90
Q

What are Phosphenes?

A

Mechanical rubbing

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91
Q

Formula for estimated pinhole VA?

A

MAR = 2.33/d

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92
Q

Formula for primary focal power of a thin lens?

A

f= - (n/F)

This is due to the primary focal point on the left side of the lens (think of ray tracing)

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93
Q

What is the apparent depth formula? Where do you expect the object to be in a medium that is larger than the area viewing from?

A

n1/l1 = n2/l2

Object will be further away, as any time you go from a small to a larger medium, the object will tend to be further away. Therefore the image will appear closer than the object.

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94
Q

Nodal point, different from the nodal ray, is located at what optical area?

A

Center of Curvature

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95
Q

Formula for Angular Magnification and what does this apply too?

A

Angular Mag = Eyepiece/Objective

This is used to subtend the image using a telescope. For instance, you are looking at the moon, the first lens when you looking at the moon will have an angle, subjective to the Objective lens. The second lens, the eyepiece lens, will create a different angle.

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96
Q

Formula for Lateral Magnification?

A

M=i/o

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97
Q

Effective Vergence Formula?

A

Fe = F1+F2 - t/n (F1xF2)

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98
Q

For a thick lens system, what is the vertex power formula?

A

F2 + F1/(1 - t/n (F1))

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99
Q

Where is the exit pupil located in a Keplarian Telescope?

A

Outside

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100
Q

Where is the exit pupil in a Galillean telescope?

A

Inside

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101
Q

Definition of Aperature stop?

A

Physical entity restricting light

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102
Q

Definition of Field stop?

A

Limits size of object that can be imaged; associated with ports

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103
Q

When using a minus lens, what happens to the Field of View?

A

Increases FOV. The opposite occurs in a plus lens.

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104
Q

Describe the Circle of least confusion?

A

Halfway point of lens, Dioptric point met in the middle of the interval of sturm.

Ex. +5.00 +2.00 x 180
+5.00 +7.00 = +12.00
+12/2 = +6 and convert into cm, therefore 17cm

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105
Q

Describe Interval of Sturm?

A

Area that covers the sphero-cylinderic area.

Ex. +5.00 +2.00 x 180
1/5 - 1/7
0.20 - 0.14 = 0.6mm = 6 cm

106
Q

Formula for Lens/Mirror Combo?

A

F = 2F1 +F2

107
Q

Formula for Mirror?

A

F=2n/f

Note: Convex mirrors have a negative ROC

108
Q

What needs to be true for Total Internal reflection to occur based on index?

A

n1>n2

As the light passes through the medium and passed the critical angle, only then will TIR occur.

109
Q

What are the most impactful abberations in order?

Curvature of Field, Distortion and Oblique Astigmatism.

A

Oblique Astigmatism >COF >Distortion

110
Q

What is the definition of Oscillopsia?

A

Standing still but the environment feels like it moves around you

111
Q

What is an example of Vertigo?

A

Environment feels still but you feel your body is moving

112
Q

At the Spiral of Tillaux, which EOM is furthest from the limbus?

A

Superior Rectus

Note: Medial Rectus is the closest

113
Q

What is the threshold for VOR?

A

<30 sec

114
Q

What is the threshold when OKN starts?

A

> 30 sec

115
Q

What does it mean when small movements occur with associated steady fixation?

A

Equal magnitude of head movement but in the Opposite direction

116
Q

What is the function of endolymph and where is it located?

A

Function: Assist in VOR

Location: Semi-Circular canal

117
Q

What is a obvious symptom associated with Spasmus Nutans?

A

Head nodding (and Pendular Nystagmus)

118
Q

Which deviation will display a comitant clinical sign, CN 6 palsy or DI?

A

DI will show, since the vergence system is still functioning and image is still on the fovea in all directions.

119
Q

What type of nystagmus is characterized by a slow drift but named in opposite direction?

A

Jerk nystagmus

120
Q

What are three tests that help in evaluatiing Nystagmus?

A

Doll Head Maneuver, Caloric test and Rotational Chair (20 sec)

121
Q

While using Visuoscopy, you notice the grid to superior to the fovea. What is the issue you have?

A

Superior Eccentric Fixation

122
Q

When conducting the Hirschberg test, what are the three criteria you are looking for in any deviation?

A

1) Look at the light and according to center of the pupil.
2) Measurement of Angle Lambda –> ESO (+) and EXO (-); This is the only test we can clinically measure
3) 1mm of deviation in approx 22PD

123
Q

Which types of medications are known to cause CE?

A

Cholinergic Agonist (Physostigmine, Pilocarpine, Sulfonamides and High dose of Vitamin B)

124
Q

What is characteristic in Dorsal Midbrain Syndrome?

A

Slow down movement on Abduction

125
Q

Where is See-Saw Nystagmus?

A

Parasellar lesion - Pituatary Gland

126
Q

Where are the 3 areas where saccades are initiated?

A

Occiptoparital Junction, FEF and Superior Colliculus

127
Q

At what point will a Pursuit transition to a Saccade?

A

50 degrees/second

128
Q

What is the definition of Tonic Vergence?

A

Measurement or Position of line of sight of each eye when stimulus for fusion at distance.

129
Q

Spectacle corrected hyperope vs. Spectacle corrected Myope, which one creates a larger retinal image size?

A

Spectacle corrected Hyperope

130
Q

What is anatomical Anisokonia?

A

PR density; causing change in the retinal size.

Note: Don’t be confused by the Stiles Crawford Effect, which displays alignment of PR’s based on light angle

131
Q

What happens to the Spectacle magnification when a Plus lens is added to a system?

A

Larger Relative Size Magnification (RSM)

132
Q

Conducting Bruckner’s test, you notice a dark retina. What does that mean?

A

Media opacity

133
Q

AC/A Ratio formula

A

PD cm +NFD mm (Phoria near - Phoria distance)

Note: Eso + and Exo -

134
Q

Gradient AC/A

A

(P1-P2)/(SA1 - SA2)

135
Q

Relative Size Magnification formula

A

New Object Size/Original Object Size

136
Q

Visual acuity testing for MAR in Low Vision

A

MAR = 20/x

137
Q

Why is ETDRS liked in Low Vision?

A

Logmar setup

138
Q

What is Kestenbaum’s rule and why is it important?

A

Reciprocal of Snellen VA to determine add power at near.

139
Q

Does Intermittent Strabismus cause Amblyopia?

A

No, only constant

140
Q

What is the pathology of Amblyopia?

A

Loss of binocular cells in the visual cortex

141
Q

What is the critical period for Amblyopia?

A

7 to 9 YO

142
Q

At which level of the brain does Suppression occur?

A

Visual Cortex

143
Q

3rd Degree fusion is usually what type of binocular attribute?

A

Stereopsis

144
Q

2nd Degree fusion is usually what type of binocular attribute?

A

Worth 4 Dot or Flat Fusion

145
Q

Which Anisometropia is worse, Hyperopic or Myopic?

A

Hyperopic Anisometropia, this is due to a clear image for a myope at 2 distances

146
Q

What type of Eccentric Fixation is opposite to direction of deviation?

A

Paradoxical EF

Ex. Esotrope & Temporal Fixation point

147
Q

List the Anisometropia range for Myopia, Hyperopia and Astigmatism.

A

M-3.00 and larger
H-1.00 and larger
A-1.50 and larger

148
Q

List the Isometropia range for Myopia, Hyperopia and Astigmatism.

A

M-8.00 and larger
H-5.00 and larger
A-2.50 and larger

149
Q

What is the most common type of ARC, other than Normal ARC?

A

Harmonious ARC

A=H and S=0

150
Q

Pt had a larger angle of anomaly than the objective angle. What type of ARC?

A

Paradoxial ARC

151
Q

Angle of anomaly is smaller than the angle of objective. What type of ARC?

A

Unharmonious ARC

152
Q

You conduct the After image test (cortical phenomenon), the OS (normal eye) is flashed with a Horizontal line and the OD (Deviated eye) is flashed with a vertical line. If the patient reports the vertical line to the left, what type of deviation does the patient have?

A

OD ESO.

Don’t confuse this with anything on the retina, rather a cortical issue.

153
Q

Bagolini lenses used and pt reports a “/" pattern. What does this mean?

A

EXO-Trope; since the image hits temporal retina.

154
Q

When is the break point from Cones to Rods in wavelength during Dark Adaption?

A

650 nm

155
Q

What is the critical duration in the scotopic system?

A

100m/s

156
Q

What is the critical duration in the photopic system?

A

10m/s

157
Q

What is the time for Cones to be saturated during dark adaption?

A

10 mins

158
Q

What is the time for Rods to be saturated during dark adaption?

A

30 mins

159
Q

What is the flash duration of Broca Sulzer effects?

A

50m/s to 100m/s

160
Q

What is the Brucke-Bartley Effect?

A

A flickering of 10Hz appears brighter than a steady light of the same luminance

161
Q

How do you notice the Purkinjee tree?

A

Closed eye and shine light

162
Q

Name a method of Ascending Limit testing?

A

Dark Adaptation

163
Q

Name a method of Descending Limit testing?

A

Visual Acuity

164
Q

Name a Stairstep method?

A

Automated Perimeter

165
Q

A relaxed pt will display what type of issue throughout Perimetry?

A

False Positive

166
Q

A Strict pt will display what type of issue throughout Perimetry?

A

False Negative

167
Q

What are the 2 important factors when summing up Total Incidence when measuring disease in a population?

A

True Positive

False Negative

168
Q

Trauma to the ON will cause what type of color defect?

A

Red-Green

169
Q

What is the most common color defect?

A

Protanolmaly

170
Q

Inherited color anomalies are usually what type of inheritance pattern?

A

X-Linked Reccessive

171
Q

What does an acquired blue-yellow color defect indicated?

A

Retina or Macula, has been impacted.

172
Q

What is the definition of linearly polarized light?

A

Magnitude changes but the direction stays the same

Circular and Elliptical polzarization are the opposite

173
Q

Explain Brewster’s law

A

PERPINDICULAR reflect light, will become refracted

174
Q

What is the general desired effect of polarization?

A

Cutting away 1/2 of the light, thus the formula–> I=I/2

175
Q

Explain Malus law

A

Intensity at a given point can be calculated based on the angle.

Ex.
Q: Unpolarized light at 45 degree, What is the intensity?

A: Since light is polarized at 90 degrees (which means 180 degree is absorbed, therefore the polarizer is already 50%) Since 45 degrees is 1/2 of 90 degrees, then it must be 1/2 of 50% of transmission.

I=I/2 at 50%
I=1/4 at 25% = 25% Transmission and 75% Absorbed

176
Q

What type of laser is used in LASIK and PRK?

A

Excimer

177
Q

Which laser is used when steepening the cornea but burning the mid-periphery?

A

Conductive Keratoplasty

178
Q

Which type of balancing test is measured via Transverse Abberation?

A

Duochrome Test

179
Q

In the periphery, would Lateral Chromatic Abberation increase or decrease?

A

Increase

180
Q

How can Chromatic Abberations be elimated?

A

With Achromatic Doublet

181
Q

On optical lenses, where is the Base Curve located?

A

Front

182
Q

Greater the Diffraction, _________ Airy’s Disk and ________ the aperture size

A

Larger and Smaller

183
Q

What is the primary cause of Chromatic Abberation?

A

Dispersion

184
Q

What is the Juvenile onset of Myopia?

A

8 to 12 YO

185
Q

What is Absolute Hyperopia?

A

Amount of hyperopia that cannot be overcome by accommodation.

186
Q

How do you correct WTR astigmatism, when the steep merideian is 90 degrees?

A

Correct with minus lenses in the 180 meridian

187
Q

Cortical cataracts will display what type of refractive shift?

A

Hyperopic shift

Note: Any peripheral cataract will display a hyperopic shift

188
Q

When doe the lens stop changing?

A

9 to 10 YO

The axial length continues to grow

189
Q

Will a hyperopic pt display esophoria or exophoria at near?

A

Esophoria this is due to increased accommodative convergence

190
Q

What is the triad for a hyperopic pt?

A

Hyperopia, miotitc pupils and Esophoria

191
Q

What is the formula for Angular Threshold?

A

Snellen Denominator = 600/CPD

192
Q

Which type of refractive error is associated with Angle Closure?

A

Hyperopia

193
Q

How tall should a 20/200 letter be at 6m?

A

87 mm taller

20/200 = 10’ and since a standard letter is 5’ gaps tall, then 5 x 10 = 50 min of arc. Then using 6m x tan(50/60 degrees)= 0.087m

194
Q

Why is Bailey Lovie considered the gold standard in Low Vision?

A

Constant spacing between letters and it can be moved to different distances for low vision patients.

Note: A Larger LogMar score on Bailey Lovie is a worse score

195
Q

If a pt get all except 2 letters on a line on the Bailey Lovie chart, what is their LogMAR score?

A

0.04

(Line score + 2) x 0.02/letter = 0.04

196
Q

What is the order when doing refraction with the JCC?

A

Axis, Power and then Axis again

197
Q

What is the best way to treat Aphakic pt’s?

A

CTL’s

This is due to magnification, as a spectacle lens will created a significantly larger image vs. CTL

198
Q

Which two types of aberrations occur only with a large aperture system?

A

Spherical Aberration and Coma

199
Q

An aphakic pt will become more esophoric or more exophoric?

A

Exophoric

200
Q

What is the theory behind Aphakics having issues with glare?

A

Since the posterior capsule is still retained, it will contain small particle or opacities that reflect light and bounce around leading to Glare. Also the pt will experience the input of Blue light entering the eye more.

201
Q

What is the most beneficial type of Soft CTL a pt should wear if they are an aphake due to Senile Cataracts?

A

Extended wear CTL’s. This is due to benefit of one package opened for an elderly pt whom may have senile issues related to bones and muscle issues.

202
Q

Where should a Bifocal line be set in pt’s?

A

Should be placed on the beginning of the lower lid.

Note: Early Accommodative Esotropia pts should have their pupil bisected

203
Q

How many refractive surfaces and index of refraction are their in the Reduced model eye?

A

One refractive and One index

204
Q

Which other axis or rays do Nodal Rays cross?

A

Optical axis

205
Q

The enterance pupil is the _______ of the aperture stop?

A

Image

206
Q

In the reduced eye, where do the Nodal Points coincide with?

A

Center of Curvature

207
Q

What is the anterior and posterior radius of the Cornea?

A
  1. 80 mm Anteriorly

6. 50 mm Posteriorly

208
Q

What angle is measured in Eccentric Fixation?

A

Kappa

209
Q

What is the order of Purkinje fibers from Largest to Smallest?

A

3, 1, 2, 4

210
Q

What are three aberrations the pupil reduces when becoming smaller?

A

Chromatic Aberrations, Spherical Aberrations and Oblique Astigmatism

211
Q

If the pupil decreases from 8mm to 2mm, what is the amount of light that is decreased by the eye?

A

By a factor of 16

212
Q

What is a corneal entopic phenomenon?

A

During a blink, tears naturally go upwards due to eyelid movement, however your eye perceives them to float down.

213
Q

Which image quality aberration is considered a 3 axis astigmatism?

A

Trefoil

214
Q

What is the definition of Modulation Transfer Function?

A

Magnitude of the Optical Transfer Function. Tells you the ability of adjacent pixels to change from black to white due to spatial frequency.

215
Q

Which law describes the adding wavelengths together?

A

Abney’s Law

216
Q

Excessive exposure to UV-___ to solar keratitis?

A

UV-C

Note: UV-A and AV-B will be mostly absorbed by the lens.

217
Q

What type of cataracts are associated with IR radiation?

A

Glass Blower Cataracts

218
Q

What is the lens clock formula?

A

F = F(Ntrue - Nair)/(Nclock-Nair)

219
Q

What is the formula for ideal base curve for a minus lens?

A

Minus = SE/2 + 6.00

220
Q

What is the minimum thickness of a Safety lens?

A

3mm

221
Q

Minimum Blank size formula

A

MBS = ED + 2d

222
Q

What is the formula for ideal base curve for a Plus lens?

A

Plus = SE +6.00

223
Q

What is the best way to correct Spherical Aberrations?

A

Achromatic Doublet

224
Q

What are the two most critical aberrations in lens design?

A

Marginal astigmatism and Curvature of Field

225
Q

How are Ghost images from spectacles reduced? 3 options

A

Increase faceform, Decrease vertex distance and Decrease eye size

226
Q

What is the maximum add for a PAL, Flat top and Bifocal?

A

Pal: +3.00
Flat top: +6.00
Round seg: +30.00

227
Q

Which frame material is known to carry memory?

A

Optyl

228
Q

Which type of frame material requires hot water for bending?

A

Nylon

229
Q

Which 2 prominent frame materials are known as hypoallergenic?

A

Optyl and Propionate

230
Q

What is the difference between Minus and Plus lens when effectivity is an issue?

A

Minus lens can be corrected by Decrease center of thickness

231
Q

Which regulatory agency is associated with lens impact resistance?

A

FDA

232
Q

What is the spherical tolerance?

A

+/-0.13D @6.50 and below; 2% @>6.50

233
Q

What is the cynlindrical tolerance?

A

+/- 0.18D @ 8.00 and below; 2% @ >6.50

234
Q

What are most Safety Rx thickness?

A

3.0mm for plastic while Polycarbonate is 2.0mm

235
Q

What is the lens impact on Z87.1 lenses?

A

1” steel ball dropped at 50” onto lens surface. Lens cannot break

236
Q

Which safety organization regulates the requirements of Z87.1 in workplaces?

A

OSHA (Occupational Safety and Health Administration)

Remember that OSHA is for workplace safety

237
Q

Formula for Effective Power?

A

F/1+dF

238
Q

K readings are 50D and above, what should you do to make sure you have an accurate reading while using the Keratometer?

A

Add +1.25 in the front of the Objective lens with anything greater than 50D

Note: -1.00 on <35D

239
Q

CTL power formula?

A

F/1-(t/n)F + F2

240
Q

Which instrument measures Base Curves?

A

Radioscope

241
Q

Which Lens Material is known to have the best deposit resistance from Group 1,2,3 and 4?

A

Group 1

Note: Group 4 is the worst

242
Q

A CTL pt gets examined and you notice blebs, which layer on the cornea are we talking about?

A

Endothelium

243
Q

Which type of small movement has the fastest amplitude?

Microdrift, Microsaccades or Microdrift

A

Microsaccade at 1 degree of arc and can reach 100 deg/arc sec

Note: Vergence system takes the longest

244
Q

What is the most common cause of Congenital Esotropia?

A

Overacting Inferior Oblique

Note: DVD and Latent Nystagmus follow suit

245
Q

What is the major cause of Myasthenia Gravis?

A

Decreased AcH receptor concentration

246
Q

What is the cause of CPEO?

A

Mitochondrial Myopathy causing muscle fibrosis

247
Q

Where is the lesion in INO?

A

MLF where the communication with CN 3,4 and 6 have been impacted

248
Q

You introduce BO prism, what do you think will happen to the fixation disparity for both eso and exophoric fixation disparity?

A

Reduction in esophoria and inducing exophoric fixation disparity

249
Q

What is easier to treat, High AC/A or Low AC/A?

A

Low AC/A, this is due to the fact the pt can compensate with accommodation.

250
Q

Which Ciliary muscle arises from anterior choroid and run to the scleral spur?

A

Longitudinal; Look at an image. Radial and Circular are more interior vs. Longitudinal is further outwards

251
Q

Which law states that an increase in brightness = an increase in intensity?

A

Weber’s law

252
Q

Based on Bloch’s law, what is the critical duration of a rod and cone?

A 
Rod = 100msec
Cone = 10 to 50 msec

Note: Bloch of Time (Temporal summation)

253
Q

When light is considered to be stationary without any flicker, what law is being impliented?

A

Granit-Harper Law

254
Q

What is the peak CFF in TEMPORAL CFF?

A

10Hz to 30Hz

Note: The peak range where no flicker is detected is 60Hz

255
Q

What is the CFF in Rods?

A

20 flashes/sec

256
Q

What is the CFF in Cones?

A

60 flashes/sec

257
Q

What law is implimented when steady light seems brighter than flockering light?

A

Brucke-Bartley effect

258
Q

Hue of a color is based on what property?

A

Wavelength

259
Q

Saturation of a color is based on what property?

A

Purity

260
Q

Brightness of a color is based on what property?

A

Luminosity

261
Q

Munsell color system is based off what 3 principles?

A

Hue, Chroma and Value

Part 1 - NBEO Prep (4 decks)

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