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Post- -trauma vision trauma vision Post Post- -trauma vision - - PDF document

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Post- -trauma vision trauma vision Post Post- -trauma vision trauma vision Post syndrome syndrome syndrome: syndrome: myopia myopia AND AND Myopia Myopia accommodative accommodative Accommodative

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SLIDE 1

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ICBO 2006 ICBO 2006

Post Post-

  • trauma vision

trauma vision syndrome: syndrome: “ “myopia myopia” ” AND AND accommodative accommodative insufficiency? insufficiency?

Steve Leslie Steve Leslie B Optom FACBO FCOVD B Optom FACBO FCOVD

ICBO 2006 ICBO 2006

Post Post-

  • trauma vision

trauma vision syndrome syndrome

  • Myopia

Myopia

  • Accommodative insufficiency

Accommodative insufficiency

  • Convergence insufficiency

Convergence insufficiency

  • Possible exotropia, exophoria

Possible exotropia, exophoria

  • Photophobia

Photophobia

  • Decreased blink rate

Decreased blink rate

  • Spatial disorientation

Spatial disorientation

  • Balance and postural difficulties

Balance and postural difficulties

ICBO 2006 ICBO 2006

PTVS symptoms PTVS symptoms

  • Diplopia

Diplopia

  • Objects appear to move

Objects appear to move

  • Visual memory problems

Visual memory problems

  • Staring behaviour

Staring behaviour

  • Poor tracking ability

Poor tracking ability

  • Asthenopic symptoms

Asthenopic symptoms

ICBO 2006 ICBO 2006

I ncidence I ncidence

  • In my experience:

In my experience:

– – Any traumatic closed head injury resulting Any traumatic closed head injury resulting in coma, with initial global effects on in coma, with initial global effects on motor and cognitive function motor and cognitive function – – Typically involves midbrain Typically involves midbrain

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SLIDE 2

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ICBO 2006 ICBO 2006

Frequency (Kowal 161 Frequency (Kowal 161 pts) pts)

  • 16% poor accommodation

16% poor accommodation

  • 19%

19% pseudomyopia pseudomyopia (55% persisted) (55% persisted)

  • “

“4 had poor accommodation despite 4 had poor accommodation despite pseudomyopia pseudomyopia” ”

ICBO 2006 ICBO 2006

Differential Differential

  • Spasm of the near reflex

Spasm of the near reflex

– – Accommodative excess Accommodative excess – – Miosis Miosis – – Esophoria/tropia Esophoria/tropia

  • Accommodative spasm

Accommodative spasm

– – Excessive accommodation tonus: should Excessive accommodation tonus: should it be excessive when measured at it be excessive when measured at distance and near? distance and near?

ICBO 2006 ICBO 2006

“ “Pseudomyopia Pseudomyopia” ”

  • The excess accommodation disappears

The excess accommodation disappears with with cycloplegia cycloplegia, but commonly recurs , but commonly recurs as as cycloplegia cycloplegia wears off (London, wears off (London, Kowal) Kowal)

  • Thus, it is excessive accommodation ie

Thus, it is excessive accommodation ie focusing closer than normal when focusing closer than normal when tested at distance, but why? tested at distance, but why?

ICBO 2006 ICBO 2006

Treatment Treatment

  • Atropinisation

Atropinisation

– – “ “Treatments using Treatments using cycloplegics cycloplegics with with sunglasses and bifocals were.. uniformly sunglasses and bifocals were.. uniformly rejected by patients rejected by patients… … (Kowal) (Kowal)” ”

  • Refractive correction, near addition

Refractive correction, near addition

  • Vision therapy: accommodative facility

Vision therapy: accommodative facility

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ICBO 2006 ICBO 2006

Neurological causation Neurological causation (London) (London)

  • “

“..shift secondary to an ..shift secondary to an irritative irritative lesion lesion that affects the parasympathetic that affects the parasympathetic innervation, resulting in innervation, resulting in ciliary ciliary body body contraction.. contraction..” ”

  • “

“secondary to neural irritation of the secondary to neural irritation of the parasympathetic third nerve parasympathetic third nerve subnucleus subnucleus, or possibly , or possibly disinhibition disinhibition of

  • f

brain stem centres.. brain stem centres..” ”

ICBO 2006 ICBO 2006

Control of Control of accommodation accommodation

  • Learned proximal information

Learned proximal information

  • Blur

Blur

  • Conscious/voluntary

Conscious/voluntary

  • Convergence

Convergence

ICBO 2006 ICBO 2006

Accommodation Accommodation… … sensorimotor sensorimotor intelligence intelligence ( ( Wachs Wachs) )

  • ..a self

..a self-

  • directed, intrinsically

directed, intrinsically constructed knowledge of body, constructed knowledge of body, physical world and practical physical world and practical use use… …( (Wachs Wachs) )

ICBO 2006 ICBO 2006

Accommodation Accommodation

  • Identification of an object fixated in space

Identification of an object fixated in space along the third dimension of the learned along the third dimension of the learned visual space construct. visual space construct.

  • The Z axis is constructed through

The Z axis is constructed through experience of the baby and child through experience of the baby and child through proprioceptive proprioceptive and and kinaesthetic kinaesthetic feedback of feedback of eye hand activities. eye hand activities.

  • Spatial construct to accurately

Spatial construct to accurately localise localise the the identification system in space. identification system in space.

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ICBO 2006 ICBO 2006

X and Y axes X and Y axes

  • Given by the egocentric laterality of

Given by the egocentric laterality of the body, and gravitational vertical of the body, and gravitational vertical of the body. the body.

  • Disturbances of the learned X and Y

Disturbances of the learned X and Y spatial coordinates (ambient system) spatial coordinates (ambient system) eg by hemianopia, or eg by hemianopia, or midbrain/brainstem trauma, could midbrain/brainstem trauma, could disrupt the basis for the Z axis disrupt the basis for the Z axis

ICBO 2006 ICBO 2006

Dark focus Dark focus

  • Location of accommodation in space in

Location of accommodation in space in the absence of visual information the absence of visual information

  • Young adults

Young adults

– – Mean 1.6D (62.5 cms), range 0 Mean 1.6D (62.5 cms), range 0-

  • 4D

4D

  • Large variations in studies

Large variations in studies

  • But individuals relatively stable

But individuals relatively stable

  • Gradual changes due to continued

Gradual changes due to continued close work close work

ICBO 2006 ICBO 2006

Dark focus Dark focus

  • Changes with nervous system activity

Changes with nervous system activity

  • Measurement by laser

Measurement by laser optometer

  • ptometer
  • Clinically measured by a

Clinically measured by a stigmatoscope stigmatoscope ie light of a retinoscope ie light of a retinoscope in a dark room in a dark room

  • But results variable

But results variable

ICBO 2006 ICBO 2006

Concept of dark focus Concept of dark focus

  • Resting point of accommodation

Resting point of accommodation

  • We focus OUT for distance tasks

We focus OUT for distance tasks

  • And focus IN for near tasks

And focus IN for near tasks

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ICBO 2006 ICBO 2006

40 cms 6 metre

Dark focus resting locus of accommodation

ICBO 2006 ICBO 2006

Mathematics! Mathematics!

  • Myopia is a relative posturing of the

Myopia is a relative posturing of the identification system closer in space identification system closer in space than the demand (zero at 6 metres) than the demand (zero at 6 metres)

  • Myopia of 1 dioptre means the

Myopia of 1 dioptre means the identification system is identification system is localising localising at 1 at 1 metre from the individual metre from the individual

  • Myopia of 2 D means it is at 50 cms

Myopia of 2 D means it is at 50 cms

  • Etc

Etc

ICBO 2006 ICBO 2006

Accommodative Accommodative insufficiency insufficiency

  • A lag of accommodation measured by near

A lag of accommodation measured by near retinoscopy at 40 cms is a measure of less retinoscopy at 40 cms is a measure of less response than the demand of 2.5 D response than the demand of 2.5 D

  • A lag of 1 D means a response of 1.5 D

A lag of 1 D means a response of 1.5 D (2.5 (2.5-

  • 1.0), and identification is

1.0), and identification is localising localising at at 67 cms 67 cms

  • A lag of 2 D indicates a spatial value of

A lag of 2 D indicates a spatial value of 2metres etc 2metres etc

ICBO 2006 ICBO 2006

Pattern of PTVS Pattern of PTVS

  • Moderate degree of myopia, and moderate

Moderate degree of myopia, and moderate to severe degree of accommodative to severe degree of accommodative insufficiency insufficiency

  • It is not accommodative spasm in the true

It is not accommodative spasm in the true sense, since there is excessive focus at sense, since there is excessive focus at distance but insufficient focus at near distance but insufficient focus at near

  • Patterns (London)

Patterns (London)

– – Transient case which resolves Transient case which resolves – – Commonly chronic but stable mild myopia Commonly chronic but stable mild myopia – – Less commonly, progressive myopia Less commonly, progressive myopia

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ICBO 2006 ICBO 2006

Post trauma vision Post trauma vision syndrome syndrome

40 cms 6 metre

Dark focus Myopia Accommodative inusfficiency Movement in towards dark focus of identification system with distance attention Movement out to dark focus of identification system with attention at near

ICBO 2006 ICBO 2006

Study data Study data

  • Randomly selected 15 records from TBI

Randomly selected 15 records from TBI patient population with: patient population with:

– – History of traumatic head injury History of traumatic head injury – – Post Post-

  • traumatic myopia

traumatic myopia – – No pre No pre-

  • existing myopia

existing myopia – – No ocular pathology (other than possible No ocular pathology (other than possible common mild optic atrophy) common mild optic atrophy) – – Age range 21 Age range 21-

  • 43

43 – – 13 males, 2 females, long term problems. 13 males, 2 females, long term problems.

ICBO 2006 ICBO 2006

  • 30

50 0.5 80

  • 1.25

80

  • 1.25

30

  • 97

36

  • 0.25

100

  • 1

133

  • 0.75

28 80 1.25 67

  • 1.5

80

  • 1.25

30 80 1.25 80

  • 1.25

80

  • 1.25

28 133 1.75 100

  • 1

133

  • 0.75

22 33 133 1.75 80

  • 1.25

100

  • 1

33 100 1.5 100

  • 1

100

  • 1

23

  • 53

80 1.25 80

  • 1.25

133

  • 0.75

24 17 50 0.5 29

  • 3.5

33

  • 3

24 36 80 1.25 44

  • 2.25

44

  • 2.25

21 20 100 1.5 80

  • 1.25

80

  • 1.25

38 100 1.5 100

  • 1

100

  • 1

33

  • 33

67 1 80

  • 1.25

100

  • 1

43 100 1.5 80

  • 1.25

100

  • 1

41 67 200 2 100

  • 1

133

  • 0.75

23 Differences MEM spatial MEM lag LE spatial LE sph RE spatial RE sph Age ICBO 2006 ICBO 2006

RE myopia RE myopia

1 2 3 4 5 6

  • 3
  • 2

. 5

  • 2
  • 1

. 5

  • 1
  • .

5 Frequency Frequ

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ICBO 2006 ICBO 2006

RE spatial locus of RE spatial locus of “ “myopia myopia” ” (cms) (cms)

2 4 6 20 40 60 80 100 120 140 160 More F r e q u e n c y

ICBO 2006 ICBO 2006

Summary Summary

  • The majority of post

The majority of post-

  • traumatic myopia

traumatic myopia is is -

  • 1.00 to

1.00 to -

  • 1.25 sphere, with

1.25 sphere, with minimal or no cylinder minimal or no cylinder

  • The visual systems, when asked to

The visual systems, when asked to attend at 6m, attend at 6m, localise localise around 1 metre around 1 metre

ICBO 2006 ICBO 2006

MEM lag (D) MEM lag (D)

1 2 3 4 5

  • .

2 5 . 2 5 . 5 . 7 5 1 1 . 2 5 1 . 5 1 . 7 5 2 2 . 2 5 2 . 5 M

  • r

e F r e q u e n c y

ICBO 2006 ICBO 2006

Accommodative near Accommodative near locus (cms) locus (cms)

2 4 6 40 60 80 100 120 140 160 180 200 More F r e q u e n c y

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ICBO 2006 ICBO 2006

Summary Summary

  • The majority of near accommodative

The majority of near accommodative response is to response is to localise localise between 60 and between 60 and 100 cms from the patient 100 cms from the patient

ICBO 2006 ICBO 2006

Difference between near Difference between near and distance loci (cms) and distance loci (cms)

2 4 6 8

  • 75
  • 50
  • 25

25 50 75 100 More F r e q u e n c y

ICBO 2006 ICBO 2006

Summary Summary

  • The most common response (6/15) of

The most common response (6/15) of the identification systems in this study, the identification systems in this study, when tested at distance and near, is to when tested at distance and near, is to localise localise in the same place in space at in the same place in space at about 1 metre from the patient. about 1 metre from the patient.

ICBO 2006 ICBO 2006

And And… ….. ..

  • Is this contiguous with the dark focus?

Is this contiguous with the dark focus?

  • Dark focus varies individually, and can

Dark focus varies individually, and can change gradually over time; we do not change gradually over time; we do not know their pre know their pre-

  • trauma dark focus

trauma dark focus

  • We are in the process of re

We are in the process of re-

  • examining these

examining these patients for dark focus and trends over time patients for dark focus and trends over time

  • I now routinely measure dark focus on all

I now routinely measure dark focus on all TBI patients TBI patients

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ICBO 2006 ICBO 2006

I mplications I mplications

  • London describes three patterns of

London describes three patterns of post post-

  • trauma myopia

trauma myopia

1 Transient cases which resolve 1 Transient cases which resolve 2 Chronic but stable, most common 2 Chronic but stable, most common 3 Progressive myopia, less common 3 Progressive myopia, less common

ICBO 2006 ICBO 2006

I n my experience I n my experience… …

  • The cases studied are all long term, chronic

The cases studied are all long term, chronic

  • problems. The transient cases may not
  • problems. The transient cases may not

present as much for care, as their present as much for care, as their neurological recovery takes precedence over neurological recovery takes precedence over transient visual needs. transient visual needs.

  • Treatment involves??

Treatment involves??

  • The majority of these chronic cases studied

The majority of these chronic cases studied show stable myopia and accommodative show stable myopia and accommodative function over time. function over time.

ICBO 2006 ICBO 2006

Hypothesis Hypothesis

  • Brain trauma can disrupt a person

Brain trauma can disrupt a person’ ’s s ability to access learned Z ability to access learned Z-

  • axis

axis sensorimotor sensorimotor control of control of accommodation in visual space accommodation in visual space

  • The system loses its ability to know

The system loses its ability to know and respond to changes in task and respond to changes in task distance distance

ICBO 2006 ICBO 2006

Hypothesis Hypothesis

  • The accommodation system essentially

The accommodation system essentially localises localises at its resting tonus ie dark focus at its resting tonus ie dark focus

  • Testing at distance shows myopia

Testing at distance shows myopia

  • Testing at near shows accommodative lag

Testing at near shows accommodative lag

  • Long term, the system builds in this new

Long term, the system builds in this new “ “learned learned” ” space, unless the system is space, unless the system is retrained at an early, plastic stage retrained at an early, plastic stage

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ICBO 2006 ICBO 2006

Using the model outlined: Using the model outlined:

  • An acute case of post

An acute case of post-

  • traumatic myopia

traumatic myopia should be managed by aggressive vision should be managed by aggressive vision therapy of accommodation, therapy of accommodation, emphasising emphasising change in space supported by change in space supported by proprioceptive proprioceptive involvement; together with involvement; together with sufficient plus at near to minimise near sufficient plus at near to minimise near visual stress. visual stress.

  • It may be possible to relearn the visual

It may be possible to relearn the visual-

  • spatial skill of focusing

spatial skill of focusing

ICBO 2006 ICBO 2006

Chronic but stable Chronic but stable… …

  • A chronic but stable case of post

A chronic but stable case of post-

  • traumatic

traumatic pseudomyopia pseudomyopia should be managed by: should be managed by:

– – Minus at distance if indicated Minus at distance if indicated – – Plus at near Plus at near – – Annual reassessment Annual reassessment

  • The patient has essentially rebuilt their

The patient has essentially rebuilt their visual space around the adaptation, and visual space around the adaptation, and cannot access the lost knowledge of how to cannot access the lost knowledge of how to

  • perate identification in space
  • perate identification in space

ICBO 2006 ICBO 2006

Progressive Progressive pseudomyopia pseudomyopia.. ..

  • Post

Post-

  • traumatic progressive

traumatic progressive pseudomyopia pseudomyopia and accommodative insufficiency should be and accommodative insufficiency should be managed by: managed by:

– – Minus at distance combined with plus at near Minus at distance combined with plus at near

  • The patient

The patient’ ’s adaptation of visual space is s adaptation of visual space is not not “ “working working” ” for them, so it continues to for them, so it continues to build as in a progressive myope, increasing build as in a progressive myope, increasing apparent myopia and reducing apparent myopia and reducing accommodative lag to an eventual lead of accommodative lag to an eventual lead of accommodation. accommodation.

ICBO 2006 ICBO 2006

Ambient visual function Ambient visual function

  • Many severe traumatic brain injuries involve

Many severe traumatic brain injuries involve the midbrain, where peripheral retinal input the midbrain, where peripheral retinal input is integrated with is integrated with proprioceptive proprioceptive and and vestibular information vestibular information

  • “

“the ambient visual process must let you the ambient visual process must let you know where you are in space and know where you are in space and essentially where you are looking before essentially where you are looking before you process information about what you are you process information about what you are looking at looking at” ” (Padula & (Padula & Argyris Argyris) )

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ICBO 2006 ICBO 2006

  • Disruption of the ambient visual process

Disruption of the ambient visual process disrupts the construct and stability of space disrupts the construct and stability of space so that the Z so that the Z-

  • axis loses reference.

axis loses reference.

  • The disruptions directly and indirectly cause:

The disruptions directly and indirectly cause:

– – Spatial disorientation Spatial disorientation – – Balance and postural difficulties Balance and postural difficulties – – Objects appear to move Objects appear to move – – Floor tilting etc Floor tilting etc

ICBO 2006 ICBO 2006

Conclusion Conclusion

  • Measure near function in TBI patients

Measure near function in TBI patients and relate it to far function and relate it to far function

  • Does patient touch change near

Does patient touch change near function (proximal information)? function (proximal information)?

  • Use lenses, prisms, and VT to re

Use lenses, prisms, and VT to re-

  • develop, or at least to stabilise

develop, or at least to stabilise adapted visual spatial judgment. adapted visual spatial judgment.