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adv orthoptics 1 > class test > Flashcards

class test Flashcards

1
Q

what are the symptoms of strabismus

A

diplopia (horizontal/vertical, binocular or monocular, can they make things single? anything make it worse?)

Awareness (deviation, some say it alternates)

pain (on motility and convergence)

headaches (where, when, lots of close work?)

asthenopia (eye strain, sore red eyes)

blurred vision

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2
Q

what anatomical factors can make px look as though they are squinting

A

epicanthus

lid anomalies

globe position

orbit and facial asymmetry

pupillary anomalies

iris anomalies

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3
Q

what tests would you use to test a baby’s vision (0-18 months)

A

forced choice preferential looking (FCPL)

Keeler or teller acuity cards
(cards with black & white stripes on right or left side)

cardiff acuity cards

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4
Q

what tests would you use to test a toddlers vision (18months - 3 years)

A

kays picture test
- single kay picture logMar
- kay picture crowded logMAR

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5
Q

what tests would you use to test a preschoolers vision

A

LogMAR crowded acuity test
(0.100 in crLogMAR = 0.200 in kays)

Sonsken

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6
Q

what vision tests should be use for each age group?

A

Age Vision Test
Birth-6mo Pref Looking

1-2 years Cardiff Cards

2-3 years Kay Pictures Single

3-4 years Kay Pictures Crowded

4-8 years Cr LogMAR

8+ years LogMAR Chart

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7
Q

what is the process called which the refractive state of the eye changes?

A

emmetropization

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8
Q

what are the classifications of amblyopia?

A

funtional type (improvement after treatment is expected)
- strabismic
- anisometropic
- stimulus deprivation
- meridional
- ametropic

  • organic: toxic - may be reversible or irreversible
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9
Q

what management is there for amblyopia?

A
  • refractive adaptation (full correction for full time wear)
  • occlusion treatment
    • (mod amblyopia 0.300-
      0.600 begin w 2 hours, no
      significant improvement-
      increase to 6)
    • severe amblyopia (0.700 or worse) FT - all waking hours or part-time - set hours per day (6 is recommended)

Atropine penalisation

Optical penalisation (rx manipulated to blur vision in better seeing eye to encourage use of amblyopic eye)

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10
Q

what are risks of occlusion

A

  • strabismic amblyopia
  • higher risk in older children
  • sbisa bar ( density of suppression) must be assessed throughout treatment

amblyopia develops in other eye (rare in PT occlusion)

dissociation in decomponsating strabismus

allergic reaction
- skin reaction to patch
- allergy to atropine

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11
Q

what are the characteristics of BV

A

fusion

Retinal Rivalry

Stereopsis

Physiological diplopia

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12
Q

what is sensory fusion

A

the ability to perceive 2 similar images - one formed on each retina and interpret them as 1

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13
Q

what is motor fusion

A

the ability to maintain sensory fusion through a range of vergence movements

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14
Q

what are signs and symptoms of visual stress/ dyslexia

A

visual processing deficits

Visual perception and spatial confusion deficits:

perceiving letters and words as reversed forms (“seeing” b as d or was as saw); general spatial orientation problems.

Imperfect representation of letters, spelling patterns, and whole words and poor memory for visual detail. Template matching

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15
Q

symptoms of visual stress

A

moving words on page

jumbling words

poor convergence

poor accommodation

diplopia

asthenopia

headaches mostly frontal

skipping words on page

losing place frequently

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16
Q

what can help with visual stress

A

coloured overlays

long term = lenses and can be assessed on colorimeter

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17
Q

what is normal bsv

A

temporal retina projects to nasal space

nasal retina projects to temporal space

fixation is normal/straight

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18
Q

what is a convergence excess esophoria

A

deviation 10^ greater at near fixation

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19
Q

what is a divergence weakness esophoria

A

deviation 10^ greater at distance fixation

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20
Q

what is a non specific esophoria

A

deviation similar at near and distance fixation

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21
Q

what is a convergence weakness EXOphoria

A

Deviation 10^ greater at near fixation

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22
Q

what is a divergence excess exophoria

A

Deviation 10^ greater at distance fixation

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23
Q

what is a non specific exophoria

A

deviation similar at near and distance fixation

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24
Q

what is a concomitant strabismus

A

the dissociated deviation remains the same whichever eye is made to fixate - no significant change in the 9 positions of gaze

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25
Q

what is incomitant strabismus

A

dissociated deviation changes size depending which eye fixates

dissociated deviation changes size when the eyes are moved in different positions of gaze

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26
Q

what are the characteristics of infantile esotropia

A
  • Onset < 6/12
  • Large up to 45^
  • Constant angle of deviation
  • Cross fixates
  • Usually alternating due to equal VA
  • Not Accommodative as no significant refractive error
  • Associated with Dissociated
    Vertical Divergence (DVD)
    and latent nystagmus
    that develops 12-18mths
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27
Q

characteristics of intermittent esotropia

A

only present under certain conditions

px have NRC, hypermetropia and high AC/A ratio

e.g. with accom element, fully accom, conv excess

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28
Q

describe the two types of ARC

A

harmonious ARC
- angle on anomaly is equal to the angle of strabismus

Unharmonious
- angle of anomaly is greater than 0 but less than deviation

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29
Q

ARC characteristics

A

occurs in long standing deviation

small angle deviation <20^

usually convergent

mild amblyopia

rare in XT

provides useful bsv in manifest strabmismus

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30
Q

microtropia characteristics

A

small angle <10^ with ARC

common

stable

anisometropia

always mildly amblyopic (one line at least)

central suppression

good but not perfect BSV

strong motor fusion

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31
Q

what is microtropia WITH identity

A

no movement on CT

only diagnose with fixation ophthalmoscope and 4^ test

ARC and eccentric fixation at same retinal point

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32
Q

microptropia WITHOUT identity

A

Small manifest deviation

Less than 10^

Mostly Esotropia but can be exotropia

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33
Q

Microtropia without identity with latent component

A

Manifest deviation will increase on continued dissociation

Must measure manifest component with simulated PCT

Measure Latent Component with full PCT

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34
Q

What 4 parts does the visual function consist of

A

light sense

form sense

Color sense

Motion sense

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35
Q

what are the purpose of rods and cones

A

rods - movement and light

Cones - colour and central vision

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36
Q

what does it mean when a deviation is

a) compensated

b) decomponsating

c) decomponsated

A

Compensated - well controlled

Decompensating = poorly controlled

Decompensated = broken down to manifest deviation

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37
Q

what is a cyclical intermittent esotropia

A

ET at near and distance at regular intervals

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38
Q

what is a consecutive esotropia

A

when px was previously XT/XP

38
Q

what factors can cause a constant esotropia with accom element

A

refractive - ET increases on accom, rx reduces size of deviation but doesnt eliminate

high AC/A ratio
ET = N>D, reduced with +3.00DS but not eliminated

38
Q

what are the characteristics for a constant ET with accom element

A

onset gradual - 1-3years

hypermetropia

anisometropia

angle reduces with correction

amblyopia

poor BSV potential - suppression, possible ARC

o/a OF MUSCLES

38
Q

what is the difference between a true and simulated near exotropia

A

true - uniocular occlusion, no change in deviation

simulated - occlusion increases distance angle

38
Q

what is a residual esotropia

A

esotropia persists after surgery for a larger angle esotropia

38
Q

EARLY ONSET ET CHARACTERISTICS

A

onset = 6mo - 2years

N=D

Amblyopia common

poor bsv prognosis despite age of onset

Deviation may increase with time

Sx management often needed

39
Q

Late onset ET characteristics

A

onset = 2-8 years

N=D

intermittent - constant large angle

diplopia

NRC

OM normal

Minor injury or short period of uniocular occlusion preceding the onset

39
Q

Esotropia acquired with myopia characteristics

A

gradual onset

progressive myopia (high -)

ET D>N

vertical deviation

seen on CT/MRI

Long eyes and older px

restricted elevation

marked abduction limitation

39
Q

What is a secondary ET and what can cause it

A

Visual loss so severe that fusion is disrupted

due to trauma, retinal detachment or cataract

40
Q

characteristics of secondary ET

A

VA loss often unilateral

Age of loss determines deviation
- after birth = ET/ XT
- childhood = ET
- Late childhood/ adult = XT

intractable diplopia

Large angle

41
Q

what is a consecutive ET

A

Px with previous Hx of XT

42
Q

causes of fully accom ET

A

refractive

High AC/A - conv excess

43
Q

characteristics of conv excess ET

A

Onset 2-5 years

Hypermetropia – +1.50-+5.00DS

Int ET to an accommodative target

Esotropia on near fixation even with full +

BSV in distance when corrected

ET N>D sgls

High AC/A ratio: often 8:1 or more

Monocular eye closure seen
Equal VA (generally)

Suppression at N when ET

44
Q

what is an intermittent cyclical ET

A

ET at near and distance at regular intervals

45
Q

what is a primary decomponsated microtropia

A

micro increased in size

uncorrected +

High AC/A

46
Q

What is a secondary microtropia

A

originally large angle tropia

angle reduced to microtropia

surgery
exercises
Optical treatment

47
Q

what is a primary microtropia

A

microtropia is the initial defect

48
Q

how to investigate central suppression in microtropia

A

bagolini

macular worth ligjts

polaroid 4 dot test

4^ prism test

fixation - visuoscope/ direct ophthalmoscope

49
Q

what management options is there for microtropia

A

aim to maintain best possible VA
- refractive error
- treat amblyopia
- treat associated strab
- occlude fellow eye

50
Q

what type of diplopia comes with right exotropia

A

Heteronymous (crossed) diplopia coming from an uncrossed eye

The image from an exotropic eye is seen on the opposite side

51
Q

what is a true and simulated intermittent distance XT

A

true - no change to angle after occlusion or on accommodation

fusion - near angle increases after occlusion - normal AC/A

Accommodation - near angle increases w accom - high AC/A

52
Q

characteristics of Int dist XT

A

Onset >6mo

Females>males

Better control at near

Suppression when manifest,
sometimes panoramic vision

Manipulation of accommodation and/ or vergence to control
Natural history variable

Manifest - inattention, poor GH, fatigue, alcohol, bright lights

53
Q

how would you know if the deviation is true or simulated int dist XT

A

mono occlusion ->

NEAR=DISTANCE ANGLE = SIMULATED DIST XT, NORMAL AC/A (FUSION)

NO CHANGE IN ANGLE ->
MEASURE NEAR ANGLE W +3.00
-> no change = true int dist xt

N=D -> Simulated dist XT w high AC/A (accom)

54
Q

what are the management options for Int Dist XT

A

refractive corection

orth exercises
alt occlusion
teach anti suppression (ONLY IF NRC)
concave lenses
prisms
tinted gls

55
Q

Intermittent neart XT

A

This is when a patient has an exotropia at near and BSV in the distance. The angle of the deviation at near is 10^ > at near than distance.

  • It can be true meaning that the angle stays the same after uniocular occlusion or

it can be simulated meaning the distance angle increases to equal the near angle after uniocular occlusion

. A simulated near exotropia is rarely seen.

  • The characteristics of a true near exotropia include asthenopic symptoms such as ocular fatigue discomfort, watering and headaches.
  • The patient usually has equal VA but may complain of diplopia.
  • They are seen to have poor binocular convergence, NRC ad normal sensory fusion but have reduced positive motor fusion amplitude.
56
Q

investigation for int dist XT

A

ORDER OF TESTING IS IMPORTANT

- Case history 
- VA- equal 
- CT (far distance) FD>D>N
- Conv 
- Bagolini
- PFR
- Stereoacuity - N&D
- AC/A- measured in distance 
- CBA - over accommodate to control so VA reduced 
- PCT 
- OM - Lateral incomitance/ A+V patterns 
- Diagnostic occlusion 
- Control Score
57
Q

primary constant exotropia

A

Exotropia is the initial defect

Early onset
- Onset < 12 months = infantile XT

Decompensated intermittent exotropia
- Distance or non specific XT decompensation

58
Q

Decompensated Intermittent XT

A

Aetiology

Characteristics

- Onset after 12mo of age 
- Hx of previously straight (photos) 
- Constant unilateral XT 
- Equal VA - amblyopia implies early 
- Suppression - no diplopia 
- NRC or ARC - difficult to determine 
- BSV - difficult to demonstrate
- BSV potential post sx - excellent

Investigations

→ Case history - old photos, monoc closure 
→ VA 
→ CT (moderate angle, all distances)
→ BSV - retinal disparity the strongest stimulus to vergence in exotropes

→ Potential for BSV 
- Age 
- VA (prognosis for fusion) 
- Prism adaptation 
- BtxA

Differential diagnosis

Careful assessment needed…
- Make sure it’s not a constant exotropia with dense amblyopia, and not a secondary exotropia

59
Q

secondary XT

A

Sensory
- Visual loss so severe that fusion is disrupted
- Age of visual loss determines the deviation

Shortly after birth pathology = ET or XT 
In childhood = ET 
Later childhood and adulthood = XT (more common)

Aetiology

Congenital or acquired vision loss
Reversible or irreversible

Characteristics

→ Gradual onset if acquired as adult - dip less

→ Large angle 

→ Hx of unilateral VA loss 

→ Age of visual loss determines deviation 

- Shortly after birth = ET or XT 
- Later childhood/adulthood = XT (more common)

Investigation

- Case history 
- Full OE 
- VA
- If aphakic, assess VA potential with refraction corrected 
- BTxA - as prognosis investigation 
- Area and density of suppression 
- PCT (synoptophore, Prism reflection test)
60
Q

Consecutive Exotropia

A

Px with previous hx of esotropia

Aetiology

Spontaneous
- Weak or absent vision
- Early onset ET, hypermetropia >5DS, amblyopia
- Gradual onset, dip

Result of surgical correction

Planned
- Primary ET c gd bsv potential
- Px with poor bsv potential - best left slightly, more stable long term result

Unplanned - most
- Early - slipped muscle
- Late - lack of binocular reflex

Characteristics

Result of surgical correction

Unplanned- most

Early - possible slipped muscle, inacurate surgery

- Diplopia

- Monoc closure (bright light) 

- Limitation of adduction 

 - presentation 20-30y/o
        - large XT (45^BI) - older larger
61
Q

residual XT

A

XT persists after surgery for larger angle

planned
- int XT/ decom x - overcorrection poorly tolerated
- diplopia if fully corrected
- two stage surgery fro large angle

unplanned
- concave lenses (smaller angles)
- BTxA into recessed LR
- BI fresnel prism
- further surgery

62
Q

Essential Infantile Esotropia

A

Aetiology

Generally unknown - multifactorial

Characteristics

Stable ET >30BO (some increase in size)
N=D angle
No sig refractive error, makes no difference
Onset <6mo,generally 3-4mo
Alternating - dense amblyopia rare (amblyopia in 41-35% chance post surgery)
Cross fixation - bilateral abduction limitation
Poor BSV prognosis
LMLN - intensity increases on occlusion - possible rotary component
DVD - >2 yrs old
IO o/a
Asymmetric motion VEPs
Asymmetry of OKN (N-T abnormal)

AHP
- Compensate for nystagmus
- Compensate abduction limitation
- Compensate for DVD (tilt)

Investigation

Case history - when did parents start noticing squint first

Refraction
VA
CR
CT
Prism reflections/ Krimsky/ PCT
Conv
OM
Dolls head test
Spinning baby test
OKN - binoc then monoc, both horiz directions

63
Q

Dissociated Vertical Deviation (DVD)

A
  • An anomaly which occurs on dissociation

Aetiology

  • Unknown
  • Thought to be related to disruption of binoc function

High incidence of latent nystagmus (as high as 100%)
Associated with infantile ET - can occur with other constant and intermittent deviations

Characteristics

Progressive elevation of the eye under the cover

Extorsion and latent nystagmus may be associated features

Fixation required

After onset of strab and nystagmus >2 y/o

After surgery for ET

Nearly always bilateral - can be very asymmetric, > in distance

Unsightly hypertropia - inattention or poor health/ fatigue

Elevation similar on ab- and ad- duction - can be spontaneous on versions(nose) - looks like IO o/a

AHP - tilt to side of fixing eye

A patterns more common

SO o/a possible

BSV weak if present at all

Investigation
- measurement is difficult
- manifest component measured with spct first
- Alt pct - each eye fixing to record asymmetry
- may be impossible to reverse movement
- can use synoptophore

reversed fixation test - differentiate between DVD and hypertropia

Bielchowsky darkening wedge test

Management

Persistent and frequent spontaneous elevation, intervention not often required

NON SURGICAL
Suggestion of manipulating rx to make fix with most affected eye

surgical - depends on
- associated IO O/A
- DVD unilateral or bilateral
- amount of asymmetry
- a-pattern with o/a SO

64
Q

Nystagmus Blockage syndrome

A

Esotropia that results from use of conv to block/ abolish manifest nystagmus and improve VA

65
Q

emmetropization

A

the process by which the refractive state of the eye changes is emmetropization

governed by active and passive factors

passive - refers to normal eye growth as eye increases, the power of the optical components decrease proportionally reducing refractive error and maintaining emmetropia

active - describes a visual feedback mechanism in the control of eye growth (visual experience)

he hyperopic element increases during the first six months
before any reduction towards emmetropia becomes apparent

  • a significant reduction in the degree of astigmatism occurs in the infants first year (? until 18 to 48 months) result of increase in eye size, concurrent flattening of cornea

nfants have some ability to accommodate to objects at different distance at 2 weeks of age, this ability increases during the first 3 months

  • cues to accommodation include blur, vergence, chromatic aberration and disparity ? which are used by infants
  • need for infants to accommodate is much less( depth of focus as a result of a smaller pupil and visual acuity )
  • the fact they do not make large accommodative efforts is related to lack of need, as much as lack of ability
66
Q

strabismus definition

A

condition in which the visual axes deviate from bi foveal fixation when fusion is absent or suspended

67
Q

characteristics of incomitant heterophoria

A

neurogenic
- angle increased when eyes turned in direction of affected muscle and decreases when turned away

mechanical
- opposite of neurogenic

myogenic

68
Q

what is a primary constant exotropia

A

exotropia is the initial defect and present under all conditions

  • early onset
  • <12 months = infantile XT
69
Q

near esotropia characteristics

A

onset 2-3 years
orthophoria at distance with bsv
ET at near
no sig refraction
equal va
normal ac/a
normal accom
bsv at near when ET neutralised
no change to ET with +

70
Q

types of diplopia

A

homonymous (uncrossed)
- distant object will double when fixating on nearer object - eso deviations
- the image of the fixating object is received on the nasal retina of the deviating eye and is therefore projected temporally it results when non-corresponding retinal points are stimulated by the same object

Heteronymous (crossed)
- nearer object will double when distant object is fixated - exo deviations
- in which the image of the fixating object is received on the temporal retina of the deviating eye and is therefore projected nasally it results when non-corresponding retinal points are stimulated by the same object

71
Q

what tests can you use to check for central suppression

A

bagolini

macular worth lights

polaroid 4 dot test

4^ prism test

Fixation - visuoscope/ direct ophthalmoscope

72
Q

intermittent near exotropia characteristics

A

XT at near X in distance with bsv

asthenopic symptoms - ocular fatique, discomofrt, watering, headaches

diplopia

equal VA

poor binoc conv

NRC

Normal sensory fusion

Reduced positive motor fusion amplitude

73
Q

intermittent distance XT

A

Characteristics

Onset >6mo
Females>males
Better control at near
Suppression when manifest, sometimes panoramic vision
Manipulation of accommodation and/ or vergence to control
Natural history variable
Manifest - inattention, poor GH, fatigue, alcohol, bright lights

Investigation - aim to assess control

ORDER OF TESTING IS IMPORTANT

- Case history 
- VA- equal 
- CT (far distance) FD>D>N
- Conv 
- Bagolini
- PFR
- Stereoacuity - N&D
- AC/A- measured in distance 
- CBA - over accommodate to control so VA reduced 
- PCT 
- OM - Lateral incomitance/ A+V patterns 
- Diagnostic occlusion 
- Control Score
74
Q

characteristics of primary constant XT

A
  • Onset after 12mo of age
    • Hx of previously straight (photos)
    • Constant unilateral XT
    • Equal VA - amblyopia implies early
    • Suppression - no diplopia
    • NRC or ARC - difficult to determine
    • BSV - difficult to demonstrate
    • BSV potential post sx - excellent
75
Q

consecutive exotropia

A

Px with previous hx of esotropia

Aetiology

Spontaneous
- Weak or absent vision
- Early onset ET, hypermetropia >5DS, amblyopia
- Gradual onset, dip

Result of surgical correction

Planned
- Primary ET c gd bsv potential
- Px with poor bsv potential - best left slightly, more stable long term result

Unplanned - most
- Early - slipped muscle
- Late - lack of binocular reflex

Characteristics

Result of surgical correction

Unplanned- most

Early - possible slipped muscle, inacurate surgery

- Diplopia

- Monoc closure (bright light) 

- Limitation of adduction 

 - presentation 20-30y/o
        - large XT (45^BI) - older larger
76
Q

investigation for infantile strab

A

Case history - when did parents start noticing squint first

Refraction
VA
CR
CT
Prism reflections/ Krimsky/ PCT
Conv
OM

Dolls head test - checks vestibular ocular reflex

Spinning baby test

OKN - binoc then monoc, both horiz directions

77
Q

DVD

A
  • An anomaly which occurs on dissociation

Aetiology

  • Unknown
  • Thought to be related to disruption of binoc function

High incidence of latent nystagmus (as high as 100%)
Associated with infantile ET - can occur with other constant and intermittent deviations

Characteristics

Progressive elevation of the eye under the cover

Extorsion and latent nystagmus may be associated features

Fixation required

After onset of strab and nystagmus >2 y/o

After surgery for ET

Nearly always bilateral - can be very asymmetric, > in distance

Unsightly hypertropia - inattention or poor health/ fatigue

Elevation similar on ab- and ad- duction - can be spontaneous on versions(nose) - looks like IO o/a

AHP - tilt to side of fixing eye

A patterns more common

SO o/a possible

BSV weak if present at all

78
Q

infantile strabismus management

A

Persistent and frequent spontaneous elevation, intervention not often required

NON SURGICAL
Suggestion of manipulating rx to make fix with most affected eye

surgery - bilateral MR recession

79
Q

what is convergence insufficiency

A

Definition: Near point of convergence is less than 10cm.

Convergence can only by maintained at this distance with effort.

Can primary or secondary.

Highly treatable.

Primary: No other causes for convergence insufficiency are present, including heterophoria

80
Q

aetiology of primary CI

A

Pre-disposing Factors:

Large interpupillary distance
Large periods of time only using distance fixation e.g., occupation

Precipitating Factors:

Fatigue from long periods of close work with/without poor lighting
Illness
Age
Medication/recreational drugs
Pregnancy

81
Q

symptoms of CI

A

Patient often reports difficulty with reading or doing close work.

Intermittent diplopia during near work.

Blurred vision during near work.

Frontal headache.

Eyestrain.

Difficulty concentrating.

Movement of print.

82
Q

investigation of CI

A

Case History

Distance and Near Vision

Cover Test and Angle of Deviation

Assessment of Convergence

Accommodation

Fusional Amplitude

83
Q

treatment for CI

A

Correction of Refractive Error

Orthoptic Exercises

Convergence Exercises:

Smooth and Jump convergence
Smooth convergence: Pen to nose exercises
Jump convergence: Dot card

Base in Prisms:
Correct near exotropia

84
Q

what is Convergence Paralysis

A

The ability to converge is completely lost.

May be primary or secondary.

Primary:
No previous history.
Investigation rules out other secondary causes.

Secondary:
Head Trauma
Neurological cause e.g., Parinauds syndrome, encephalitis, multiple sclerosis.

85
Q

characteristics of convergence paralysis

A

Diplopia for all distances nearer than infinity.

Exotropia at near.

Ocular motility is normal in primary convergence paralysis.

Accommodation may or not be impacted.

86
Q

Management of Convergence Paralysis

A

Once secondary convergence palsy is ruled out/underlying cause is investigated…

Conservative management:

Base in prisms to correct exo deviation.
Occlusion to prevent diplopia.
If accommodation is impacted, hypermetropic prescription in combination with base in prisms.

Botox to lateral rectus may be temporary fix

87
Q

Convergence Spasm

A

Excessive convergence.
May also be associated with accommodation spasm.

Transient episodes of convergence.

Needs to be differentiated fromother causes of esotropia e.g., sixth nerve palsy.

Convergence Spasm will demonstrate:

Full ocular motility- full abduction.
Pupil miosis when convergence.
Dolls head- full eye movement.

Patients with convergence spasm may be suffering from significant stress in other aspects of their life.

Spasm may be exacerbated with testing- not seen when simply chatting to patient about other things.

Management: Reassurance and relaxation techniques.

Cycloplegic drops and plus lenses may be useful in short term.

adv orthoptics 1 (1 decks)

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