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Physiological optics and Binocular Vision > Binocular Vision > Flashcards

Binocular Vision Flashcards

1
Q

ESSENTIALS FOR BINOCULAR VISION:

A
  1. Healthy functioning maculas
  2. Efficiently working muscular mechanism (motor fusion)
  3. Efficiently working neural mechanism (sensory fusion)
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2
Q

proper coordination of eyes and brain

A

NEUROPLASTICITY

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3
Q

PREREQUISITES FOR SINGLE BINOCULAR VISION:

A
  1. Frontally placed eyes, overlapping retinal fields
    Straight eyes, without deviation
  2. Partial decussation of the optic nerve fibers
  3. Foveal region stimulated
  4. Corresponding or identical retinal points
  5. Size of retinal images Must be equal or nearly equal in size
  6. Efficient function of extra ocular muscles and nerves
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4
Q

equal size of retinal images

A

ISEIKONIA

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5
Q

unequal size of retinal images

A

ANISEIKONIA

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6
Q

equal best corrected visual acuity

A

ISO-OXYOPIA

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7
Q

unequal best corrected visual acuity

A

ANISO-OXYOPIA

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8
Q

significant/ high difference of refractive error

A

ANISOMETROPIA

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9
Q

eye has different refractive status

A

ANTIMETROPIA

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10
Q

extent of BINOCULAR VISUAL FIELD

A

180 degrees

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11
Q

extent of COMMON BINOCULAR VISUAL FIELD

A

120 degrees

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12
Q

extent of MONOCULAR VISUAL FIELD

A

150 degrees

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13
Q

extent of TEMPORAL CRESCENT

A

30 degrees

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14
Q

Advantages of Binocular Vision

A
  1. Single vision - first and foremost advantage
  2. Optical defects in one eye are made less obvious by the normal image of the other eye
  3. Enlarged field of vision
  4. Power to discriminate details and contours of an object is better with two eyes than with one eye
    alone
  5. Loss of one eye will not seriously handicap the individual
  6. Stereopsis or depth perception
  7. Compensation of blindspot and other differences
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15
Q

development of binocular vision at birth

A
  • Eyes are not associated with each other; act as two different organs
  • VA: not greater than 5/200
  • normally hyperopic - because ciliary muscles are not yet fully developed and smaller eyeball
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16
Q

development of binocular vision in newborn

A

first sign of development of fixation appears when the eyes follow light

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17
Q

development of binocular vision at 2 months

A

eyes follow large objects

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18
Q

development of binocular vision at 3 months

A
  • Foveas fully formed
  • They hold objects
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19
Q

development of binocular vision at 3-4 months

A

Eyes are expected to be straight

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20
Q

development of binocular vision at 6 months

A

fixates at an object for 1-2 minutes

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21
Q

development of binocular vision at 1 yr old

A

VA of 20/70

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22
Q

development of binocular vision 1-1 ½ yr old

A

fusional mechanism becomes fully developed

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23
Q

development of binocular vision at 3 yrs old

A
  • VA: 20/20
  • Accommodation develops with sharpening of visual acuity
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24
Q

development of binocular vision at 7-12 yrs old

A

Age of emmetropization

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25
Q

A reading matter is positioned at 40 cm/16 inches in front of the patient’s eye; a pen is positioned 2-3 inches over the printed page, so that some of the letters are hidden from the left and other from the right eye. If the patient reads the next text continuously without hesitation, BV is present

A

BAR READING TEST

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26
Q
  • Sufficient amount of prism (usually 6 prism BU or BD) is placed before one eye to induce doubling
  • if patient notices diplopia, BV is present
A

Prism test

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27
Q

Light passing through a prism is bent towards the?

A

BASE

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28
Q

EYE looking through a prism is displaced on the?

A

APEX

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29
Q

OBJECT viewed through a prism is displaced on the

A

APEX

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30
Q

A rolled paper with 2 or fewer diameters is placed before one eye, and is directed at a distant fixation object. The observer’s hand is held up, palm facing the observer at a distance object viewed through the tube

If the patient notice an apparent hole in the hand, BV is present

A

HOLE IN THE HAND

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31
Q

binocular-like instrument consisting of prism: it makes use of a SEPTUM to separate the image seen by the right and left eye

A

STEREOSCOPE

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32
Q
  • Pressure on temporal side of the eyeball is applied
  • If the patient reports doubling of objects in the visual field, BV is present
A

PRESSING THE EYEBALL

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33
Q
  • Position which the eyes assume when with the head erect, point straight ahead on the horizon is fixed upon.
  • Ortho position
A

PRIMARY POSITION

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34
Q

Position in which the eyes assume when the lateral or vertical movements are involved Dextro, levo,supra infra

A

SECONDARY POSITION

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35
Q
  • position in which the eyes assume when it moves in a direction which is a combination of both lateral and vertical movements
  • dextrosupra, dextroinfra, levosupra, levoinfra
A

TERTIARY POSITION

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36
Q

origin of inferior oblique muscle

A

Inferior Nasal orbital rim

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37
Q

Strongest, heaviest, broadest EOM

A

MEDIAL RECTUS

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38
Q

EOM that is angled 23 degrees nasally

A

SUPERIOR RECTUS & INFERIOR RECTUS

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39
Q

longest EOM, about 60mm in length

A

SUPERIOR OBLIQUE

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40
Q

points of connections of all
recti muscles

A

Spiral of Tillaux-

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41
Q

Cross diagram that shows which muscle
move when the eye moves to a given
direction

A

BENZENE RING

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42
Q

AXIS

 24 mm
 Horizontal line from vertex of the cornea to posterior pole of the eye
 Torsional movement

A

Optic axis/ Y-axis/antero-postero/sagittal axis

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43
Q

AXIS

 22 mm
 Line passing through the center of rotation of the eyeball and at right angle to
optic axis
 Vertical movement

A

Transverse axis/X-axis

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44
Q

AXIS

 22mm
 Superior-inferior line passing through center of rotation
 Horizontal movement

A

Vertical axis/ z-axis/supero-infero axis

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45
Q

 Lie the optic axis and transverse axis
 Divides eyeball to upper and lower portion

A

Horizontal Plane

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46
Q

 Lie the optic axis and vertical axis
 Divides eyeball to right and left hemispheres

A

Median Plane

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47
Q

 Lie the transverse axis and vertical axis
 Divides eyeball to anterior and posterior halves

A

Equatorial Plane

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48
Q

Image of the real pupil found at the cornea.

A

ENTRANCE PUPIL

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49
Q

Point towards which the observer directs his gaze.

A

OBJECT OF REGARD

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50
Q

Point located 13.5 mm behind the cornea.
◦ All oblique axes pass and it is where the movement of eyes
take place.

A

CENTER OF ROTATION

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51
Q

Line drawn from the object of regard to the center of
rotation.

A

LINE OF SIGHT

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52
Q

Line drawn from the object of regard to the fovea passing through
the nodal point.

A

VISUAL AXIS

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53
Q

Line from the center of entrance pupil and passes through the
center of curvature of the cornea.
◦ Line perpendicular to the cornea and passing through the center
of the entrance pupil of the eye.

A

PUPILLARY AXIS

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54
Q

An imaginary straight line passing through the midpoint of the
cornea (anterior pole) and the midpoint of the retina (posterior
pole).

A

OPTIC AXIS

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55
Q

Line connecting the centers of rotation of both eyes.

A

BASELINE

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56
Q

Plane which includes both the object of regard and baseline.

A

PLANE OF REGARD

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57
Q

Line in the primary position of the plane of regard which
bisects the baseline

A

PRIMARY SAGITTAL LINE

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58
Q

Plane tangent to the chin and the two super-ciliary ridges.

A

FACE PLANE

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59
Q

Conscious and purposeful fixation at an object of regard

A

VOLUNTARY

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60
Q

Involuntary fixation such as may occur in response to
peripheral retinal stimulation

A

REFLEX

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61
Q

A rapid change of fixation from one point in the visual field to
another

A

SACCADIC/JUMP FIXATION

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62
Q

Continued fixation of a moving object, implying a dynamic
movement of the eye so as to keep the image of the object
continuously on the fovea

A

PURSUIT

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63
Q

Series of rapid fixations associated with an attempt to survey
quickly the details of a view subtending a relatively large area
of the visual field

A

SCANNING

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64
Q

Continuous and fixed fixation of a non-moving object for a
given period of time

A

STEADY

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65
Q

Retinal elements of the two eyes that
share a common subjective visual
direction are called?

A

CORRESPONDING
RETINAL POINTS.

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66
Q

 Holds that if the two images of an object fall on
upon identical points in the two retinas, the object
is seen as one,
 but if the two images fall upon unidentical or
disparate points, the object is seen as two.

A

DOCTRINE OF
CORRESPONDING POINTS

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67
Q

 A theoretical circle passing through the fixation point
and nodal points (entrance pupil) of the two eyes;
 any point from such circle stimulates corresponding
retinal elements.

A

HOROPTER

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68
Q

A zone infront or behind the horopter in which an
object may lie and still be seen as a single image
despite stimulating non-corresponding elements.

A

PANUM’S FUSIONAL SPACE

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69
Q

 Process by which a single cortical image is
perceived as a result of two separate
ocular ones
 Blending of sight

A

FUSION

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70
Q

 States that fusion operates upon a
psychological and cerebral level

A

WORTH’S THEORY

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71
Q

 “Theory of Replacement”/ “Theory of Retinal
Rivalry”
 Based upon alternate shifting mosaic patterns
from each ocular image, in which portions of
ocular image of one eye combines with
portions from the other, in varying pattern to
form the final unified or single perceptual
image

A

VERHOEFF’S THEORY

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72
Q

Maintains that single image is merely a
projection of two identical images to
the same perceptual position and that
two ocular images are perceived as one
because of their community location

A

WALL’S THEORY

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73
Q

REQUIREMENTS FOR FUSION

A

 Equal or nearly equal visual acuity between two
eyes
 Monocular fixation of each eye
 Normal sensorial relationship or normal retinal
correspondence
 Normal ocular motility
 Representation of the crossed and uncrossed
optic nerve fibers in the occipital cortex

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74
Q

 COMPENSATORY ACTIONS May be due to problem with oblique muscles

A

HEAD TILLTING

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75
Q

COMPENSATORY ACTIONS

 FACE TURNING
◦ Due to lateral problems (esotropia/exotropia)

A

 FACE TURNING

76
Q

COMPENSATORY ACTIONS

 Due to vertical problems
(hypertropia/hypotropia)

A

 CHIN DEPRESSION/ ELEVATION

77
Q

 Occurs when the amplitude of accommodation
(AA) is lower than expected for the patient’s age
and is not due to sclerosis of the crystalline lens.
 usually demonstrates poor accommodative
sustaining ability.

A

ACCOMMODATIVE INSUFFICIENCY

78
Q

 is a condition in which the AA is
normal, but fatigue occurs with
repeated accommodative stimulation
 Accommodation is sufficient but tires
easily

A

ILL-SUSTAINED ACCOMMODATION /
ACCOMMODATIVE FATIGUE

79
Q

 occurs when the accommodative system is slow
in making change, or when there is considerable
lag between the stimulus to accommodation and
the accommodative response
 Difficulty in changing the accommodative state
from one fixation distance to another.
 Patients experience difficulty in changing focus
quickly

A

ACCOMMODATIVE INFACILITY /
ACCOMMODATIVE INERTIA

80
Q

 is a rare condition in which the
accommodative system fails to respond
to any stimulus
 Total inability to accommodate due to
ciliary paralysis

A

ACCOMMODATIVE PARALYSIS

81
Q

 Condition in which the ciliary muscle is
contracted and cannot be relaxed;
accommodation is continously exerted
 may be associated with fatigue
 It is sometimes part of a triad
(overaccommodation, overconvergence, and
miotic pupils) known as spasm of the near
reflex (SNR).

A

SPASM OF ACCOMMODATION

82
Q

 Exo at near > Exo at distance
 Shows decompensated exophoria for
near vision, but not for distance.

A

Convergence weakness

83
Q

 Exo at distance > Exo at near
 In its typical form, this is an intermittent
divergent squint for distance vision with
compensated exophoria for near vision.

Sometimes it is defined as an exo-
deviation of 15^ greater for distance vision

than for near.

A

Divergence excess

84
Q

 Exo at distance = Exo at near
 Type of exophoria whose degree does
not differ significantly with the fixation
distance

A

Basic (mixed) exophoria

85
Q

 Eso at distance > Eso at near
 Shows decompensated esophoria for
distance vision. In near vision, the
heterophoria will be compensated.

A

Divergence
insufficiency/weakness

86
Q

 Eso at near > Eso at distance
 Type of esophoria with low degree for
distance vision but on converging for near
vision, the convergence impulses seem to
be unusually high. This results in a high
degree of esophoria for near vision.

A

Convergence excess

87
Q

 Eso at distance = Eso at near
 The patient with basic esophoria has high
tonic esophoria at distance, a similar
degree of esophoria at near

A

Basic (mixed) esophoria

88
Q

often have normal phorias and AC/A ratios but reduced
fusional vergence amplitudes.
 Their zone of clear single binocular vision
(CSBV) is small.

A

FUSIONAL VERGENCE
DYSFUNCTION

89
Q

Position assumed by the visual axes when fusion
is suspended.

A

RELATIVE POSITION OF REST

90
Q

assumed by the eyes in death before the onset of
rigor mortis, and in deep anesthesia

A

ABSOLUTE POSITION OF REST

91
Q

 the deviation is, within physiologic limits and for a given
fixation distance, the same in all directions of gaze

A

COMITANT/CONCOMITANT

92
Q

 one or more extraocular muscles show signs of
underaction or paralysis.
 The deviation therefore varies in different directions of
gaze but is larger when the eyes are turned in the
direction of action of the underacting or paralytic
muscle.

A

INCOMITANT/NONCOMITANT

93
Q

CLASSIFICATIONS OF HETEROTROPIA that occurs only at certain fixation distance

A

PERIODIC

94
Q

CLASSIFICATIONS OF HETEROTROPIA that occurs within the first 6 months of life

A

INFANTILE

95
Q

CLASSIFICATIONS OF HETEROTROPIA when deviation of the eye occurs after 6 months

A

ACQUIRED

96
Q

Reflex eye movements that stabilize images on
the retina during head movements by
producing an eye movement in the direction
opposite to head movements, reserving the
image on the center of the visual field.

A

Vestibulo-ocular reflex

97
Q

The patients’ head is turned fairly and briskly to right and left to
elicit horizontal eye movement or the chin is tilted up and down to
elicit vertical eye movement

A

Doll’s head movement

98
Q

This test is based on the observation of the conjugate deviation of
the infants’ eyes in response to head movement induced by
rotation

A

Swinging baby test

99
Q

Is the tendency of the eye to deviate inward when
fusion is interrupted

A

ESOPHORIA

100
Q

Is the tendency of the eye to deviate outward when
fusion is interrupted

A

EXOPHORIA

101
Q

 the influence of atmospheric conditions (dust,wind,
vapor) in so far as visibility is concerned, is known
to us all.
 In extreme clearness of mountain air, we judge
objects to be much closer and smaller than they
really are. On the other hand, because of the
indistinctness of the outline of objects in foggy
weather, we hold them to be situated at a great
distance and therefore and they appear
correspondingly large.

A

Aerial Perspective

102
Q

Parallel lines extending before us appear to
converge. This aids us very largely in our perception
of depth and constantly employed by artist to lend
proper perspective to their work. Object located at
more converging points seem to be farther, objects
located at less converging points/diverging appear
to be nearer.

A

Mathematical Perspective

103
Q

the apparent displacement of
an object, seen from two different points in space,
or when seen by the two eyes alternately.

A

Motion parallax

104
Q

MONOCULAR CUES OF DEPTH
PERCEPTION wherein The speed of the image can also determine the distance of the object

A

Velocity

105
Q

sum of the angles formed between
the visual axes and the line connecting the object to
the part of the retina outside the fovea

A

Parallactic angle

106
Q

Superimposition or simultaneous (first
degree fusion) of two ocular images (e.g.,
a bird in the cage) requires stimulation of
retinal areas having common visual
directions.

A

Superimposition/Simultaneous
Perception

107
Q

 true fusion without stereopsis
 It is defined as sensory fusion in which
the resultant percept is two-dimensional,
that is, occupying a single plane as may
induced by viewing a stereogram in which
the separation of all homologous points is
identical.

A

Flat Fusion

108
Q

 Highest form of fusion
 Ability to judge distant objects

the binocular visual perception of three-
dimensional space based on retinal disparity.

A

Stereopsis/Depth Perception

109
Q

Diplopia occurring in normal binocular vision for non-fixated
objects whose images stimulate disparate points on the retina
outside of the Panum’s area.

A

PHYSIOLOGICAL DIPLOPIA

110
Q

◦ Any diplopia due to an eye disease(e.g. Proptosis),
◦ an anomaly of binocular vision (e.g. Strabismus),
◦ a variation in the refractive index of the media of the eye
(e.g. Cataract)
◦ a subluxation of the crystalline lens
◦ or to a general disease (e.g. Multiple sclerosis, myasthenia
gravis).

A

PATHOLOGICAL DIPLOPIA

111
Q

movement of one eye only

A

DUCTION-

112
Q

synchronous and symmetric movement of
both eyes in the same direction

A

VERSION-

113
Q

synchronous and symmetric movement
of both eyes in the opposite direction

A

VERGENCE-

114
Q

right eye turns up
and left eye turns down

A

POSITIVE VERTICAL DIVERGENCE-

115
Q

right eye turns
down and left eye turns up

A

NEGATIVE VERTICAL DIVERGENCE-

116
Q

vertical
meridians of both eyes rotate inward

A

INCYCLOVERGENCE/CONCLINATION-

117
Q

vertical
meridians of both eyes rotate inward

A

EXCYCLOVERGENCE/DECLINATION-

118
Q

Ways of Dissociating the eyes

A
  • by covering one eye
  • by presenting dissimilar targets
  • by using colored filters
  • by using prism
119
Q

refers to esotropia which begins in the developmentally and neurologically normal child during the first 6mos of life. probable age of onset is at 2-4 months

A

Infantile esotropia

120
Q

the
incoordianted
dissociations of infancy
before BV is developed

A

Spurious strabismus

121
Q

strabismus when both eyes down

A

Catatropic

122
Q

strabismus when both eyes up

A

anatropic

123
Q

strabismus when both eyes turn up and in

A

Braids

124
Q
  • associated with the activation of Acc.
  • attributed partly to either uncorrected
    hyperopia and/or high Accommodative
    Convergence/Accommodation (AC/A)
    ratio.
A

Accommodative Esotropia

125
Q

management of accommodative esotropia

A

1.Correction of hyperopia and/or prescribe
near add
2.Tx of amblyopia if present
3.Vision Therapy

126
Q

management of infantile esotropia

A
  1. Correction of EOR
  2. Tx of amblyopia if present.
    ⚫Occlusion therapy on the preferred eye.
    (Direct occlusion)
    ⚫2hrs daily. Should be monitored every 4-
    6weeks.
  3. Surgical ocular alignment
127
Q
  • not associated w/ accommodative effort
  • correction of hyperopia and/or
    prescribing near add has minimal or no
    effect
A

Non-Accommodative Esotropia

128
Q
  • caused by a mechanical restriction or
    tightness or a physical obstruction of the
    EOM
  • can either be congenital or acquired
A

Mechanical Eso/Exo

129
Q

management for Mechanical Eso/Exo

A
  1. May need no specific therapy if there s
    either minimal or no strabismus in the
    primary position
  2. Prisms for slight head turns
  3. Surgery for large head turns
130
Q
  • px sometimes manifests diplopia,
    suppresion, or ARC
  • w/ Tx, may either progress, stay the
    same, or in some cases, improve
  • rarely deteriorates to constant exotropia
A

Intermittent Exotropia

131
Q

management of intermittent exotropia

A
  1. Case to case basis in therapy
  2. Correction of EOR. Full amt. of myopia,
    anisometropia and astigmatism. Hyperopia
    may be undercorrected for younger
    patients.
  3. Prism therapy to facilitate fusion
  4. Vision Therapy
  5. Surgery
132
Q
  • results from a primary sensory deficit or as a

result of surgical intervention.

A

Secondary Eso/Exo

133
Q
  • results from visual deprivation or trauma in one
    eye.
  • uncorrected anisometropia, unilateral cataract,
    corneal opacity, etc.
  • occurs more frequently under 5 years of age
A

Sensory Eso/Exo

134
Q
  • results from visual deprivation or trauma in one
    eye.
  • uncorrected anisometropia, unilateral cataract,
    corneal opacity, etc.
  • occurs more frequently under 5 years of age
A

Sensory Eso/Exo

135
Q

management of of sensory eso/exo

A
  1. Cataract surgery w/n the first 2 months of
    life
  2. optical correction w/ CL
  3. IOL
  4. Occlusion therapy
  5. Prisms
  6. Vision Therapy
136
Q
  • occurs after surgical overcorrection
  • may result in amblyopia in children and
    diplopia in adults
A

Consecutive Eso/Exo

137
Q
  • angle of deviation is less than 10PD
  • constant and usually unilateral
  • frequently results from the Tx of a larger scale
    deviation.
A

Microesotropia & Microexotropia

138
Q

This occurs when placing a neutral density
filter over one eye. When you close the
eye with the filter the object looks brighter.
The visual system does not add the
brightness from the 2 eyes.

A

Fechner’s Paradox

139
Q

Fibers in that interconnect the two
hemispheres.

connects the left side of the brain to the right side, each side being known as a hemisphere

A

Corpus Collosum

140
Q

Lesion at Corpus Collosum

A

Loss of stereopsis along the midline

141
Q

Lesion at Corpus Collosum

A

Loss of stereopsis along the midline

142
Q

Both fovea have a common visual
direction and the retinal elements nasal to
the fovea in one eye corresponds to the
retinal elements in the other eye.

A

Normal Retinal Correspondence

143
Q

Retinal correspondence when
the fovea of one eye has a common visual
direction with an extrafoveal area in the
other eye.

A

Abnormal Retinal Correspondence

(ARC)

144
Q

In which the angle of anomaly is equal to the
objective angle of deviation. This
indicates that the ARC fully corresponds to the
strabismus.

A

Harmonious ARC

145
Q

In which the angle of anomaly is less than
the objective angle of deviation

A

Unharmonious ARC

146
Q

When the angle of anomaly is greater than
the objective angle of deviation.

A

Paradoxical ARC

147
Q

Unification of Visual excitations from
corresponding retinal images into a single
visual percept = a single visual image.

An object localized in one and the same visual
direction by stimulation of the two retinas can
only appear as one.

A

SENSORY FUSION

148
Q

• The precise co-ordination of the two eyes for
all direction of gazes.

• refers to the vergence movements made by
the eyes in response to retinal disparity and
having the result of obtaining or maintaining
images on corresponding retinal points.

A

Motor Fusion

148
Q

• The precise co-ordination of the two eyes for
all direction of gazes.

• refers to the vergence movements made by
the eyes in response to retinal disparity and
having the result of obtaining or maintaining
images on corresponding retinal points.

A

Motor Fusion

149
Q

(1950) described the motor fusion as fusion
compulsion.

A

Ogle

150
Q

To screen for the presence of third
degree of fusion.

A

RANDOM DOT E

151
Q

the basic instrument
used for measuring or
training binocular vision,
for stimulating vision in
an amblyopic eye and
for increasing fusion of
the eyes.

A

major amblyoscope

152
Q

One maintained that humans are born without
binocularity or spatial orientation and that
binocularity and spatial orientation are learned
functions acquired by trial and error through
experience and assisted by all the other senses,
especially the kinesthetic sense.

A

Empiricism or Ontogenic development.

153
Q

Binocular vision and spatial orientation are not
learned functions but are given to humans with
the anatomicophysiologic organization of his
visual system, which is innate.

A

Nativism or Phylogenic development.

154
Q

Unilateral or less commonly, bilateral
reduction of best corrected visual acuity that
can not be attributed directly to the effect of
any structural abnormality of the eye or the
posterior visual pathway. Defect of central
vision.

A

Ambylopia

155
Q
  • The most common form of amblyopia

thought to result from
competitive or inhibitory interaction between
neurons carrying the nonfusible inputs from
the two eyes.
◼ Which leads to domination of cortical vision
centers by the fixating eye and chronically
reduced responsiveness to the nonfixating eye
input.

A

Strabismic Amblyopia

156
Q

◼ Second in frequency
◼ It develops when unequal refractive error in the two
eyes causes the image on the one retina to be
chronically defocused.
◼ This condition is thought to result:
- Partly from the direct effect of image blur in the
development of visual acuity.
- Partly from intraocular competition or inhibition

A

Anisometropic Amblyopia

157
Q

hyperopic or astigmatic anisometropia (1 - 2D)

A

mild amblyopia

158
Q

Mild myopia anisometropia (less than -3D)

A

usually doesn’t cause amblyopia

159
Q

unilateral high myopia (-6D)

A

severe
amblyopia visual loss.

160
Q

result from large,
approximately equal, uncorrected refractive
error in both eyes of a young child.

A

isometropic amblyopia

161
Q

Hyperopia exceeding 5D & myopia excess of
10 D has a risk of?

A

bilateral amblyopia

162
Q

Uncorrected bilateral astigmatism in early
childhood may result in loss of resolving
ability limited to chronically blurred
meridians.

A

Meridional amblyopia:

163
Q

◼ It is usually caused by congenital or early
acquired media opacity.
◼ This form of amblyopia is the least common
but most damaging and difficult to treat.
◼ In bilateral cases acuity can be 20/200 or
worse.

A

Stimulus Deprivation Amblyopia

164
Q

children younger than 6 years with
congenital cataract that occupy the central 3
mm. or more of the lens,

A

capable of causing severe amblyopia.

165
Q

a form of amblyopia deprivation
caused by excessive therapeutic patching.

A

Occlusion amblyopia

166
Q

allow
the examiner to test the crowding phenomenon with
isolated optotype. Bar surrounding the optotype
mimic the full optotype to the amblyopic child.

A

Crowding bar, or contour interaction bars,

167
Q

allows the examiner to test the crowding phenomenon with
isolated optotype. Bar surrounding the optotype
mimic the full optotype to the amblyopic child.

A

Crowding bar, or contour interaction bars,

168
Q

Treatment of amblyopia involves the following
steps:

A

◼ Eliminating (if possible) any obstacle to vision
such as a cataract
◼ Correcting refractive error
◼ Forcing use of the poorer eye by limiting use
of the better eye.

169
Q

Designed primarily for screening pre-school children

(age 2.5 to 5 yrs)
for defects of
binocular vision.

A

TNO TEST

170
Q

other terms for strabismus

A
  • squint,
  • manifest ocular deviation,
  • tropia, ophtahlmotropia
  • heterotropia, cross eyes,
    wall eyes.
171
Q

Classification of Strabismus

A
  1. By the nature of the deviation (comitant/incomitant)
  2. By behavior (fixed/variable)
  3. By appearance (manifest/latent)
  4. By time/frequency/periodicity (Constant/intermittent/periodic)
  5. By eye (monocular/bilateral/alternating)
  6. By direction (eso,exo,hyper,hypo)
172
Q

(1977) presented sinusoidal
gratings at various orientations and spatial
frequencies to normal and strabismic
subjects.

A

Schor

173
Q

occurs at a later age than infantile esotropia usually, normal binocular vision has existed prior to the onset of the condition

A

acquired esotropia

174
Q

a convergent strabismus which develops suddenly without apparent etiology in school-aged or adult patients with previously normal binocular vision

A

acute esotropia

175
Q

caused by mechanical restriction or tightness of an EOM or a physical obstruction of the EOM

A

MECHANICAL ESOTROPIA

176
Q

for the patient to experience comfort, the fusional reserve should be twice or more than twice the fusional demand

A

Sheard’s criterion

177
Q

often is used to describe amblyopia, which is potentionally reversible by occlusion therapy

A

functional amblyopia

177
Q

often is used to describe amblyopia, which is potentionally reversible by occlusion therapy

A

functional amblyopia

178
Q
  • amblyopia in which ocular pathology is not obvious
  • refers to irreversible amblyopia
A

Organic amblyopia

179
Q

period of highest risk of deprivation amblyopia

A

few months to 7 or 8 yrs

180
Q

amblyopia which is due to causes such as hysteria or malingering. common in children and adults in stressful situations

A

Psychogenic amblyopia

180
Q

amblyopia which is due to causes such as hysteria or malingering. common in children and adults in stressful situations

A

Psychogenic amblyopia

181
Q
  • a suppression that occurs wherein only when the eyes are misaligned
  • example is intermittent exotropia
A

Facultative suppression

182
Q

a suppression that is present at all times, irrespective of whether the eyes are deviated or straight

A

Obligatory suppression

Physiological optics and Binocular Vision (12 decks)

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