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1 Strab > MT2 > Flashcards

MT2 Flashcards

1
Q

How to therapeutically reduce confusion

A

use occlusion: Binasal, single nasal, direct occlusion, indirect occlusion

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2
Q

Divergent Excess (Non-Strabismic)

A

Exo at distance and near with distance 10pd > near
Ex: 10XP’, 25XP NO troping!

Observation: Unilateral eye closure in bright light. Glare causes difficulty with binocularity.

Better control at near that allows stereo and active convergence tone in children

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3
Q

Divergent Excess STRABISMUS

A

Constant OR intermittent XT at far
Triggered by inattention, fatigue, illness, day dreaming
***This is a near problem manifesting in the distance. Near findings may look normal at first. Over sustained testing, near findings will begin to break down.

Secondary adaptation to sustained near point stress.

May achieve panoramic vision- as they alternate, they suppress.

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4
Q

2 secondary adaptations to sustained near point stress

A
  1. Develop myopia. More common pathway. Lets distance vision go blurry but keeps both channels on.
  2. Develop DE strabismus. Less common. Keep distance vision clear but turn off a channel.
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5
Q

How to test for DE strab

A

Do sustained near CT and look for it to vary over time. Want sustained turn with no change over time.

Repeat BO vergences and look for 50% decrease in breaks.

Variable near phobias on repeated testing.

Occlusion test for 30-45 mins. DE will have no change.
+3.00D lens test. DE will have big increase in exo.

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6
Q

How to treat DE strab

A

Train w standard VT for binocular dysfunctions. Don’t need to treat as a strab. Train them when they are straight.

There will be no AP!

Even after therapy, eyes may drift while daydreaming.

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7
Q

Cyclic strabismus

A

Alternate straight and turned days. May last for months to years.

Tx: have 2 different glasses and use binasal occluders on the glasses for the strab day. Then enforce bilaterally in the body.

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8
Q

Crossed diplopia

A

Exo, heteronymous

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9
Q

Uncrossed diplopia

A

Eso, homonymous

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10
Q

Explain diagram of esotropia with normal projection

A

Whole eye is turned– pt uses fovea which differs from point zero. No pseudo fovea.

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11
Q

Explain diagram of esotropia with harmonious AP

A

Eye is turned. Pt does not use fovea.

Pt uses pseudo fovea (a) and point zero. Same place.Right in front of the eye- where it would normally face.

Harmonious= amount of reprogramming matches eye turn. This helps the patient

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12
Q

When can you get AP

A

Only in esotopes at a young age

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13
Q

Esotropia with unharmonious AP

A

Unharmonious= amount of reprogramming is anything other than the amount of turn.

Pseudo fovea is in between the actual fovea and point zero.

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14
Q

Why develop an AP?

A

Limit confusion.

Image from the whole eye is NOT reprogrammed. Only a small zone.

Once the programming is done, it is NOT permanent.

Once established, the software is NOT always used. Can have multiple sets

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15
Q

AP is more likely to come out under which settings? Not likely to come out when?

A

Natural, like bagolini lenses.
Less likely to come out under odd settings such as after image flashes.

It is not an all or nothing!

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16
Q

Accommodative esotropia

  • Onset at which age?
  • Associated with which two things?
  • traditional treatment
  • Etiology
A
  • Onset at which age? 3-5 years
  • Associated with which two things? High hyperopia and ACA
  • traditional treatment: Prescribe full cyclo Rx. Throw plus at them.
  • Etiology: Seems to be associated with high fever, seizure, acute severe illness, emotional event, near drowning. The eyes don’t suddenly change. Physiological.
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17
Q

Active. What is it? how do you make a person have a more active system? what might it cause?

A

Active: Attention directed into the visual process. High degree of concentration into a small volume of space. High stress.
Give less plus (less hyperopia compensated for) –> more active

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18
Q

Passive. What is it? how do you make a person have a more active system? what might it cause?

A

Attention is diverted to other sensory modalities or thoughts. Not directed to objects in space. Attention distributed to large volumes of space. Less stress.

Give more plus –> more passive –> More likely to not have control over sight, flight instead of fight, develop an eye turn in demanding situations.

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19
Q

“The plus is the scaffold we erect to build the house of binocularity” Refers to?

A

Accommodative ET.

One should build the least complex scaffold needed (plus). Once house (binocularity) is built, can slowly remove the scaffold (plus).

Plus doesn’t fix the problem- may even make them more hyperopic.

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20
Q

Adverse hyperopia

A

Hyperopia in excess of a double buffer that decreases visual performance.

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21
Q

Hyperopia buffer

A

+0.75D
Double buffer is +1.50D

Allows visual system to be stressed, but can still maintain clear VA. Refraction changes throughout the day. Trend is to become more myopia in the day- rebuild with sleep and nutrition.

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22
Q

Most adverse hyperopia is secondary to

A

iatrogenic illness caused by overzealous prescribing of plus. Dr has intention of fixing things, but makes it worse.

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23
Q

How to prescribe keeping in mind the hyperopia buffer

A

Leave at least a single buffer to as much as a double buffer uncompensated AT DISTANCE unless the patient has specific needs or demands.

Rx plus (less is best. The more you put on, the longer it will take to take off)–> VT –> reduce the plus

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24
Q

How to Rx for +1.00 to +3.00D first timer

A

Watch very closely. Maybe prescribe Rx for near if the pt is in school.

Younger and higher the hyperopia = shorter F/U time

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25
Q

How to Rx for +3.00D and above with no trope

A

Provide the min lens necessary to get the child interacting with their environment in an efficient manner.

Rx 1/3 the measured power as a started. Re-exam in 3-6 months.

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26
Q

How to Rx for +3.00D and above with trope

A

Use min amount of plus to get the eyes straight with stereo.

Rx 1/3-1/2 the measured power.

Re-exam in 4-12 weeks

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27
Q

The younger the patient the ____ time between re-evals

The older the patient the ____ time between re-evals

A 
Younger= shorter 
Older = longer
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28
Q

When cutting plus after VT for an accommodative ET patient, what is the main rule

A

Must Rx the same amount of plus at near in the new Rx as there was total plus power in the old Rx at DISTANCE

New Rx total near power = old Rx distance power

If possible, reduce compensatory lens to allow for double buffer.

Old RX: +5.00 with +1.75D add
New subjective: +5.00D

Cut new subjective by +1.50 for double buffer.
Distance Rx is +3.50D

Distance + near power must equal the old distance Rx, which is +5.00D
Give them a +1.50D add

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29
Q

True or false

It is easier to help a patient with a larger residual angle who is active rather than one with a small residual angle who is passive

A

True

30
Q

Duane’s Retraction Syndrome

A

Congenital. Mono or bino. Actual mechanical problem in the orbit. The muscle may be not present, calcified/mostly connective tissue, or malformed.

When the medial rectus pulls, the eye moves back in the socket and the interpalpebral fissure narrows since eye is not pushing against lids.

Lack of ability to move the affected eye out (abduct). Generally, the eye can’t move past primary gaze.

31
Q

Brown’s classification of Duane’s (Less used)

A

Type A: Limited abduction more so than limited adduction

Type B: Limited abduction. Normal adduction

Type C: Limited adduction more so than limited abduction. Causes eye turn and head posture change.

32
Q

Huber’s classification of Duane’s (More common)

A

I: Limited abduction.
II: Limited adduction.
III: Both limited

33
Q

Frequency of Duane’s types

A

Most common is type I, which is limited abduction.

34
Q

James Mims says the traditional classification of Duane’s retraction syndrome should be abandoned. Why

A

traditional thoughts- Actual mechanical problem in the orbit. The muscle may be not present, calcified/mostly connective tissue, or malformed.

Now thinking that it is a result of developmental adaptations that occur in the embryo as a result of absence of the 6th cranial nerve. LR is un-innervated

35
Q

Brown’s Tendon Sheath Syndrome

A

Similar to Duanes. Involves the superior oblique being stuck on the trochlear.

Hallmark: Decreased ability to look upward.

36
Q

Superior Oblique Palsy

  • What does it look like
  • Management
A

Hyper deviation of affected eye, inability to depress eye when ADDucted. Causes head tilt and chin depression.

If less than 10-12 pd, consider prescribing prism to achieve binocular vision and VT.

If more than 10-12 pd, consider surgical referral with VT before. Try prism to see if they are capable of fusion before referring !

37
Q

Strabismus Fixus

A

Rare, congenital, stationary, large angle esotropia.

May be due to fibrosis of the medial rectus muscles. Usually no abduction is possible and surgery on the tight muscles is of little benefit.

38
Q

Going from aniso glasses to CL

A

During versions, glasses will induce different prism effects, which are accounted for by the patient. When they switch to CL, there is no induced prism. They will have to rewrite software.

39
Q

Most vertical misalignments are secondary to other problems such as

A
  1. Posture- Functional leg length difference, actual leg length difference, scoliosis, torticollis.
  2. horizontal- Fix the horizontal and the vertical will fix itself.
  3. Hardware- Affect muscles, ligaments, blow out fractures, or secondary to EOM surgeries. Generally hard to eliminate. Help the pt use the system to the fullest.
  4. Trauma or disease- do VT to speed up the healing process. Start soon unless there is muscle entrapment.
40
Q

Ludlam states to change the underlying phoria/tropia posture, the patient needs to work with _____

A

Jump dictions. Instead of compensating with ranges, this is truly helping the patient fix the underlying problem.

Leap frog glasses Rx

41
Q

When should you do surgery

A

to solidify/embed the gains

Work to expand the volume of space where they easily use both channels together

Improve the quality of seeing in all areas of space

42
Q

When do kids notice eye turns in other children?

A

Negative attitude towards strabismus emerges at 6 years.

No gender effects. No effect even if the child is strabismic.

43
Q

4 classifications of amblyopia

A
  1. Strab
  2. refractive
    - Due to aniso
    - Bilateral blur leading to bilateral amblyopia
    - Meridional
  3. visual deprivation
    - Occlusion amblyopia due to prolonged patching, cataract, or ptosis.
  4. toxic
44
Q

Strabismic amblyopia

A

Due to abnormal binocular interaction. One eye is turned, therefore the image is not hitting corresponding retinal points. Causing diplopia or confusion. To reduce this, brain suppresses.

45
Q

Refractive amblyopia

A

Usually one blurred image and one clear image. Active neural reorganization will occur so that the patient will not use the fovea of the amblyopic channel.

Greater the asymmetry –> greater the amblyopia.

  • Could have bilateral blur, which leads to bilateral amblyopia
  • Meridional amblyopia. with greater than 3.00DC

Prescribing the full compensatory lenses for aniso may promote further adaptation and make the amblyopia worse.

46
Q

Visual deprivation amblyopia

A

Occlusion amblyopia may be due to prolonged patching, congenital cataracts or ptosis. With lack of light, the visual pathway fails to develop. Visually devastating! Very minimal improvement in acuity when treatment is prescribed.

47
Q

Does strab cause:

Abnormal binocular interaction ?
Deprivation of form vision amblyopia?

A

Yes

No

48
Q

Does aniso cause

Abnormal binocular interaction ?
Deprivation of form vision amblyopia?

A

Yes

Yes

49
Q

Does unilateral vision deprivation cause

Abnormal binocular interaction ?
Deprivation of form vision amblyopia?

A

Yes

Yes

50
Q

Does bilateral vision deprivation cause

Abnormal binocular interaction ?
Deprivation of form vision amblyopia?

A

No

Yes

51
Q

Toxic Amblyopia

  • What is the consequence?
  • What could cause it
A

The consequence is central or peripheral vision loss.

Tobacco, methyl alcohol, lead poisoning, dental infections.

52
Q

Gold standard of amblyopia treatment

A

Occlusion

Types: Direct, inverse, alternating

53
Q

patching

-Occlusion options

A

opaque patch, bandaid, cling patch/bangerter filter, CL, pharm

54
Q

Direct occlusion

A

Stimulate fovea of amblyopic eye by occluding the good eye.

Acuity must be good enough in amblyopic eye to perform daily activities.

Will not address or fix eccentric fixation !!!!!!!!!

55
Q

Indirect occlusion

A

Prevent eccentric fixation from being embedded

ARC doesn’t exist monocularly, so ARC pattern isn’t reinforced, just like with direct occlusion.

56
Q

What happens after you take the patch off? What are better alternatives

A

After you take the patch off, the eyes will eventually go back to their original positions. Will not hold up over time.

Need to integrate the two sides to lead to long term solution that remains in tact. Some penalization is ok to balance but need integration.

Better idea to use binasal or mono nasal patch to reduce forces causing confusion. Allows both channels to be on at the same time.

Could also try dichoptic viewing. Results in greater learning effects than monocular training.

57
Q

40 hours of monocular trainings = same improvement of 10 hours dichotic training.

A

Suggests suppression of amblyopic eye gates plasticity within the adult cortex.

58
Q

Bangerter occlusion foils for penalization filters

A

Decreases high spatial frequency data, while low spatial frequency data is unaltered.

Can be used to balance out the two visual channels.

As you decrease the foil number, it increases blur or decreases VA.

59
Q

For lay observers, what is the minimal observable angle

A

For lay observers: 14.5 pd in ET, 8 dp in XT

60
Q

General thoughts about testing

A

Get in and get out. Do it fast.

61
Q

During unilateral cover test. We are watching during which part?

A

The cover part.

62
Q

Howell Card

A

Subjective test. Use maddox rod horizontally over eye. Then have them look OU and they tell you where the vertical line appears.

63
Q

How to look for non concomitancy

A

Observe with your face as target with small movements to different directions of gaze.

Do CT in different fields of gaze.
Hess Lancaster type testing ?????

64
Q

Angle kappa

A

Angle formed between the visual axis and the pupillary axis at the NODAL POINT of the eye

Pupillary axis is where the pupil is pointing- turned eso or exo.

65
Q

Angle Lamba

A

Angle formed between visual axis and pupillary axis at the ENTRANCE PUPIL. Clinically, this is what we measure.

66
Q

How to measure angle kappa/lamba

A

Always measure monocularly with light source directy in front of the examiner.

Have person look directly at the light.

(+) when reflex is nasal
(-) when reflex is temporal

Normal is +2.6-+5

67
Q

Hirschberg test

-Simpleton vs formal approach

A

Simpleton uses a light in the room that is reflected in the corneas.

Formal approach- use a light source at 40cm on midline.

68
Q

Hirschberg test.

1mm is how many pd

A

1 mm = 12 degrees = 22pd turn

69
Q

Krimsky

A

Insert prism to achieve centered K reflex

70
Q

4pd BO test

A

Looks for micro ET and small central scotoma.

Pt looks 3-5 feet away.
Insert prism quickly in front of fixating eye.
Observe movements of the other eye.

Should see a + version (both eyes move towards the apex) This causes diplopia. Then should see a vergence of the other eye to achieve singularity.

(+) version and (-) Vergence = suppression of eye without prism.
(-) version and (-) vergence = suppression of eye with prism.

If you place prism in front of suspected strab eye, you will not see movements.

71
Q

Parks 3 step

A

Step 1: Which eye is hyper.

  • Circle depressors of hyper eye
  • Circle elevators of hypo eye

Step 2: In which gaze does hyper increase? R or L

  • Circle right positions if right gaze is worse
  • Circle left positions if left gaze is worse

Step 3: Does hyper get worse with head tilt (R or L) in primary gaze? (diagonal)

  • Circle right positions of right head tilt is worse
  • Circle left positions if left head tilt is worse

1 Strab (2 decks)

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