Dynamic Aspects of accommodation and vergence accommodation and - - PowerPoint PPT Presentation

Dynamic Aspects of accommodation and vergence accommodation and vergence in mild traumatic brain injury

A retrospective analysis of a clinical p y population conducted by the Brain Injury Group at SUNY College of Optometry

Brain Injury Group at SUNY,College of Optometry SUNY,College of Optometry

• Dr Kenneth J Ciuffreda
• Dr Kenneth J Ciuffreda
• Diana Ludlam
• Wesley Green
• Dora Szymanowicz

y

• Preethi Thiagarajan

Four Components of A d i Accommodation

Bl d i d i

• Blur-driven accommodation
• Response to defocus blur
• Vergence accommodation
• Vergence accommodation
• Response to disparity (fusional) vergence
• Proximal accommodation

Proximal accommodation

• Response to apparent/perceived nearness
• Tonic accommodation
• Results from baseline autonomic neural inervation (elicited in the

absence of blur, disparity, and proximal cues)

Brain Injury Definitions Brain Injury Definitions

• Acquired Brain Injury (ABI)

Acquired Brain Injury (ABI)

– Occurs after birth – Sudden-Onset – Non-Progressive – TBI is a subgroup of ABI

Brain Injury Definitions Brain Injury Definitions

• Traumatic Brain Injury (TBI)

Traumatic Brain Injury (TBI)

• Often due to an external force
• Either open or closed-head
• In coup-contrecoup injury there is diffuse

axonal injury, shearing, and swelling j y, g, g

• Typically more global, less localized

yp y g ,

Epidemiology of TBI in the U S Epidemiology of TBI in the U.S.

• Approximately 1 5 million TBI injuries each year of which

Approximately 1.5 million TBI injuries each year of which 95% require hospitalization or emergency room treatment

• Many require subsequent medical and rehabilitative services (e.g.,

y q q ( g vision, physical, occupational, cognitive therapy)

• Motor vehicle accidents are the primary cause of TBI for people aged

5 to 75 years 5 to 75 years

• The highest rates of TBI occur in the young (<5 years) and elderly

(>75 years) populations, owing primarily to falls ( y ) p p g p y

• There is a higher incidence of TBI among males across all age

groups

Iraq and Afghanistan War Fighters Iraq and Afghanistan War Fighters

• Estimates are 23-32% of injured war fighters experience

j g p TBI

• Over 90% of combat related TBI’s are closed head
• Over 90% of combat-related TBI s are closed-head

injuries that may be either mild or occur in conjunction with more visually obvious injuries

• It is likely that many injured war fighters with TBI go

undiagnosed and potentially continue active duty g y y

• Blast injuries have caused the most war-related TBI’s

Visual Symptoms in TBI Visual Symptoms in TBI

Accommodatively-based symptoms

• Eye focusing problems
• Blur

E t i d i l f ti

• Eyestrain and visual fatigue
• Avoidance of near tasks
• Oculomotor-based reading difficulties

Oculomotor based reading difficulties

• Headache
• Intermittent diplopia

Visual Signs in TBI

• Accommodatively–based

– Reduced amplitude of accommodation – Increased lag of accommodation – Slowed Accommodative Facility – Reduced relative accommodation Reduced relative accommodation – Uncorrected hyperopia/astigmatism (due to an inability to compensate accommodatively) compensate accommodatively) – Restricted fusional vergence ranges at near related to d ti i t ti bl accommodative interactive problems

Previous Literature Findings Previous Literature Findings

• Three reported accommodative diagnoses

Three reported accommodative diagnoses related to mTBI

– Accommodative insufficiency (most prominent) – Accommodative excess or ”pseudomyopia” – Accommodative infacility

Accommodative Insufficiency (AI) Accommodative Insufficiency (AI)

• Several studies reported AI in 10-33% of subjects when

p j comparing measured accommodative amplitude with normative literature values

• A retrospective study reported 22% of returning veterans

seen at a VA clinic manifested decreased accommodative amplitude accommodative amplitude

• One study reported 16% of mTBI patients exhibited

y “poor accommodation” when using accommodative amplitude and/or PRA as the diagnostic parameter

Pseudomyopia Pseudomyopia

• Researched less often than AI.
• One study reported 19% of the mTBI subjects

y p j exhibited pseudomyopia

– No history of prescription for myopia – Patient reports blur at distance correctible with minus Patient reports blur at distance, correctible with minus lenses C f – Cycloplegic refraction in emmetropia, low hyperopia

Accommodative Infacility Accommodative Infacility

• Ohtsuka and Sawa (1997) reported on a 29-year-old male

ti t ith i f th t i i f th patient with agenesis of the posterior vermis of the cerebellum

• Objective, dynamic accommodative responses of the

patient and a visually-normal control subject were compared when tracking a sinusoidally-modulated blur compared when tracking a sinusoidally modulated blur stimulus Th ti t hibit d i ifi tl l i l di

• The patient exhibited significantly less accuracy, including

an increased lag (i.e., error) and a decreased response amplitude (i.e., gain) at all three of the relatively slow t l ti l f i th f d i th t l temporal stimulus frequencies, than found in the control subject

Accommodative Infacility Accommodative Infacility

Patient Control Patient Control T A

0.1 Hz

T A A

0.2 Hz

3D T A A

0.3 Hz

4 s A

(Adapted from Ohtsuka and Sawa, 1997)

Accommodative Infacility Accommodative Infacility

• Kawasaki et al (1993) reported on a 20-year-old female

patient with a subtentorial arachnoid cyst

• This patient exhibited normal dynamic accommodative

responses to a slowly modulated ramp stimulus, but manifested significantly abnormal dynamic g y y accommodative responses, including reduced and variable response amplitude, to repetitive predictable step stimuli

• After surgical removal of the cyst, however, the patient

regained normal accommodative responsivity to the di t bl t ti li predictable step stimuli

Accommodative Infacility Accommodative Infacility

4 5 6

stimulus e (D)

1 2 3 4

modation s response

• 1

1 10 20 30 40 50 60

Accomm and

10 20 30 40 50 60

Time (s)

(Adapted from Kawasaki et al, 1993)

Accommodative Infacility Accommodative Infacility

Preoperation Step stimuli Right eye Left eye 4D 10 s e t eye Postoperation Step stimuli Right eye Left eye 4D 10 s Left eye

(Adapted from Kawasaki et al, 1993)

Recent Retrospective Findings f R h G from our Research Group

• We investigated several accommodative parameters in a

large mTBI population from our clinic

• We also determined the functional outcome of mTBI

patients after conventional optometric vision therapy

• A computer-based query of the medical records over a

three-year period uncovered 160 individuals with mTBI, y p , 51 of these being under 40 years of age (i.e., prepresbyopic), and therefore having received extensive accommodative testing

Recent Retrospective Findings from our Research Group

Ocular motor Percentage (%) Most common

Percentage of individuals with TBI (n= 160) with a specific category of ocular motor dysfunction and the most common anomaly

Ocular motor dysfunction Percentage (%) Most common anomaly Accommodation 41.1 Accommodative insufficiency su c e cy Versional 51.3 Deficits of saccades Vergence 56.3 Convergence insufficiency Strabismus 25.6 Strabismus at near CN palsy 6.9 CN III palsy Note: The "n" representing the number of persons tested for accommodation Note: The "n" representing the number of persons tested for accommodation

• nly includes those under the age of 40 years (i.e., prepresbyopic), "n" = 51.

(Adapted from Ciuffreda et al, 2007)

Recent Retrospective Findings f R h G from our Research Group

Accommodative Accommodative Accommodative Ill-sustained Total with

Number of individuals (n = 51) with a specific category of accommodative dysfunction

Accommodative insufficiency Accommodative infacility Accommodative excess Ill-sustained accommodation Total with accommodative dysfunction 19 2 2 21 19 2 2 21

Note: Some persons presented with more than one accommodative dysfunction. The

"n" represents the number of persons tested for accommodation, which only included those under the age of 40 years (i.e., prepresbyopic). 21/51 = 41.1% of persons with TBI presented with an accommodative dysfunction. (Adapted from Ciuffreda et al, 2007)

Recent Retrospective Findings f R h G from our Research Group

• Thirty three of the 160 mTBI patients completed a
• Thirty-three of the 160 mTBI patients completed a

conventional optometric vision therapy program Thi t f th thi t th (90%) i d k dl i t

• Thirty of the thirty-three (90%) improved markedly in at

least one sign and one symptom, which represented “successful treatment”

• This suggests that accommodative deficits, along with
• ther oculomotor problems, in mTBI patients can be

fully/partially remediated using relatively simple fully/partially remediated using relatively simple therapeutic procedures

(Ciuffreda et al, 2008)

Recent Prospective Findings f R h G from our Research Group

• Using both subjective and objective techniques,

we investigated numerous static and dynamic f d i i b h li i l d aspects of accommodation in both clinical and laboratory settings.

• The findings were compared to either a visually-

normal control group or normative literature

• a co t o g oup o
• at e te atu e

values.

Static Measurement Findings Static Measurement Findings

Mean Push-up Accommodative Amplitude (TBI vs Age Matched Duane's Values) (TBI vs Age-Matched Duane's Values)

8 10

e

4 6 8

mmodative litude (D)

2 4

Accom Amp

TBI OD TBI OS Duane's Mono TBI OU Duane's Bino

(Green et al, 2010)

Static Measurement Findings

Accommodative amplitude characteristics and deviation from Duane's mean normative values in 12 subjects with mTBI.

Subject Age (yrs) PU amplitude OD (D) PU amplitude OS (D) PU amplitude OU (D) ML amplitude OD (D) ML amplitude OS (D) Absolute Deviation from Duane's Mean Norms Percentage Deviation from Duane's Mean Norms (D) (%) TBI-A1

26 6.50 8.00 6.50 3.50 7.50

• 3.70
• 36.3

TBI-A2

40 4.25 3.87 3.75 3.25 3.25

• 2.45
• 39.5

TBI A3

34 9 00 7 12 8 37 4 00 3 50 0 37 4 6

TBI-A3

34 9.00 7.12 8.37 4.00 3.50 0.37 4.6

TBI-A4

36 5.00 5.00 5.50 1.25 1.25

• 1.90
• 25.7

TBI-A5

28 4.00 5.25 5.00 3.75 4.00

• 4.70
• 48.5

TBI-A6

25 8.25 7.12 10.00 6.00 6.25

• 0.40
• 3.8

TBI-A7

27 7.12 6.00 8.37 6.50 5.00

• 1.63
• 16.3

TBI-A8

40 3.62 3.75 3.87 3.00 4.75

• 2.33
• 37.6

TBI-A9

28 5.75 7.37 6.87 3.25 4.25

• 2.83
• 29.2

37 5 87 5 37 7 12 3 00 3 50 0 00 0 0

TBI-A10

37 5.87 5.37 7.12 3.00 3.50 0.00 0.0

TBI-A11

37 6.00 3.50 6.25 5.25 3.75

• 0.85
• 13.6

TBI-A12

18 14.25 14.25 14.25 9.00 8.75 2.15 17.8

Mean:

31.33 6.63 6.38 7.15 4.31 4.65

• 1.52
• 19.0

Std Dev:

6.95 2.90 2.90 2.90 2.06 2.03 1.89 20.5

SEM:

2.01 0.87 0.87 0.87 0.59 0.59 0.57 6.2

(Green et al, 2010)

Static Measurement Findings

Accommodative Amplitude in Mild Traumatic Brain Injury Patients

18.0 14.0 16.0

e (D)

Push-up OU Push-up OD Push-up OS

• Poly. (Duane's Mean Norms)
• Poly. (Duane's Max Norms)
• Poly. (Duane's Min Norms)

10.0 12.0

ive Amplitude

4 0 6.0 8.0

Accommodati

0.0 2.0 4.0

A

10 20 30 40 50 60

Age (years)

(Green et al, 2010)

Static Measurement Findings Static Measurement Findings

Comparison of accommodative amplitude mean values between the Parameter Direction of change in mTBI Normal vs mTBI p p mTBI group and normative literature values (p<0.05) Parameter change in mTBI group Normal vs. mTBI Monocular push- d ti D 8 23D 6 51D up accommodative amplitude Decrease 8.23D vs. 6.51D Binocular push-up Binocular push-up accommodative amplitude Decrease 8.68D vs. 7.15D (Adapted from Green et al, 2010)

Static Measurement Findings g

Mean Accommodative Stimulus/Response Slope Values Slope Values

0.8 1.0 0 4 0.6 0.8

Slope

0.2 0.4

S

0.0 Normal Mono TBI Mono Normal Bino TBI Bino

(Green et al, 2010)

Static Measurement Findings g

Monocular Accommodative Stimulus/Response

6

y = 0.872x - 0.281 R2 = 0.9999 (Normal)

5

se (D)

(Normal) y = 0.7779x - 0.0973 R2 = 0.9974 (TBI)

3 4

tive Respons

Normal TBI Linear (Normal)

1 2

Accommodat

Linear (TBI)

1 1 2 3 4 5 6 7 8

A d ti Sti l (D) A Accommodative Stimulus (D)

(Green et al, 2010)

Static Measurement Findings g

Binocular Accommodative Stimulus/Response Curve

6

y = 0.8117x - 0.1576 R2 = 0.9985 (Normal)

5

se (D)

(Normal) y = 0.8092x - 0.1762 R2 = 0.9994 (TBI)

3 4

tive Respons

Normal TBI Linear (Normal)

1 2

Accommodat

Linear (TBI)

1 1 2 3 4 5 6 7 8

A d ti Sti l (D) A Accommodative Stimulus (D)

(Green et al, 2010)

Static Measurement Findings g

Mean Tonic Accommodation

1.0

tive D)

0.5

• mmodat

sponse (D

0.0

Acco Res Normal TBI

(Green et al, 2010)

Static Measurement Findings

Measurements of AC/A ratio, PRA/NRA, and heterophoria in twelve subjects with mTBI.

Subject AC/A ratio (PD/D) PRA (D) NRA (D) Horizontal near phoria (PD) Vertical near phoria (PD) ( ) TBI-A1 4.20

• 3.75

3.00 5 eso TBI-A2 2.75

• 1.25

1.25 8.5 exo TBI-A3 5.50

• 0.75

0.50 3.25 eso TBI A4 6 00 1 00 1 00 11 eso TBI-A4 6.00

• 1.00

1.00 11 eso TBI-A5* 6.65

• 2.50

1.50 4 exo 2 L. Hyper TBI-A6 2.70

• 0.75

2.75 3.5 exo TBI-A7 4.30

• 2.00

3.75 5.5 eso 1 L. Hyper TBI-A8** n/a

• 1.25

2.50 14 eso TBI-A9

• 0.53
• 2.00

2.75 2.75 exo 0.5 L. Hyper TBI-A10

• 2.50

2.75 6 exo 2 R. Hyper TBI-A11 3.00

• 1.75

2.50 TBI-A12 2.00

• 7.25

2.50 7.25 exo 1 R. Hyper Eso (N=5) Exo (N=6) Ortho (N=1) Mean: 3.32

• 2.23

2.23 7.75 5.33 0.54 Std Dev: 2.31 1.80 0.95 4.54 2.28 0.78 SEM: 0.70 0.52 0.27 2.03 0.93 0.23

* Patient manifested a dramatic increase is esophoria with the 3.50D and 4.50D stimuli (AC/A) ** Patient was not able to perform task due to excessive tearing (AC/A)

(Green et al, 2010)

Static Measurement Findings g

• AC/A ratio

– Two subjects manifested ratios at or above 6 PD/D, which is considered j , abnormally high – Three exhibited ratios at or below 2 PD/D, which is considered abnormally low – One subject was unable to perform the task due to highly excessive tearing th t f tl lt d h th ti t b l f ti d that frequently resulted when the patient became overly fatigued – Therefore, 50% (6/12) of the individuals with mTBI exhibited abnormality in the stimulus AC/A ratio

• PRA/NRA

– 50% (6/12) exhibited either reduced values for both PRA and NRA or an NRA value exceeding the PRA value by 1.00D or more

• Heterophoria

– Five exhibited esophoria T hibit d h i f t th i i di t – Two exhibited exophoria of greater than six prism diopters – Therefore, 64% (7/12) manifested values outside of the normal near range

Dynamic Measurement Findings

D i St R (N l 3) S ( ) Dynamic Step Response (Normal-3)

3.5 4 4.5 5

sponse (D)

Dynamic Step Response (TBI-A8)

3.5 4 4.5 5

sponse (D)

1 1.5 2 2.5 3

commodative Res

1 1.5 2 2.5 3

commodative Res

0.5 20 40 60 80 100 120 140

Time (s)

Acc

0.5 20 40 60 80 100 120 140

Time (s)

Acc

Dynamic Step Response (TBI-A9) Dynamic Step Response (TBI-A10) Dynamic Step Response (TBI A9)

3 3.5 4 4.5 5

esponse (D)

y p p ( )

3 3.5 4 4.5 5

Response (D)

1 1.5 2 2.5 3

Accommodative R

0 5 1 1.5 2 2.5

Accommodative R

0.5 20 40 60 80 100 120 140

Time (s)

A

0.5 20 40 60 80 100 120 140

Time (s)

A

(Green et al, 2010)

Dynamic Measurement Findings

Dynamic Step Response (Normal 2) Dynamic Step Response (Normal-2)

3.5 4 4.5 5

sponse (D)

1 1.5 2 2.5 3

commodative Res

0.5 5 10 15 20 25 30 35

Time (s)

Acc

Dynamic Step Response (TBI-A9)

5 3 3.5 4 4.5 5

Response (D)

0 5 1 1.5 2 2.5

Accommodative R

0.5 5 10 15 20 25 30

Time (s)

A

(Green et al, 2010)

Dynamic Measurement Findings

Normal-5

3 4

Tau = 0.243 s ative (D)

Normal-5

3 4

Tau = 0.251 s ative (D)

1 2 3

• Ampl. = 1.73 D

PV = 7.1 D/s Accommod Response

1 2 3

• Ampl. = 1.75 D

PV = 7.0 D/s Accommod Response

0.0 0.5 1.0 1.5

Time (s)

0.0 0.5 1.0 1.5

Time (s)

TBI-10 TBI-10 TBI 10

3 4

Tau = 0.838 s Ampl = 2 07 D

• dative

se (D)

TBI 10

3 4

Tau = 0.459 s

• Ampl. = 1.36 D
• dative

se (D)

1 2

• Ampl. = 2.07 D

PV = 2.5 D/s Accommo Respon

1 2

p PV = 3.0 D/s Accommo Respon

0.0 0.5 1.0 1.5 2.0

Time (s)

0.0 0.5 1.0 1.5 2.0

Time (s)

(Green et al, 2010)

Dynamic Measurement Findings Dynamic Measurement Findings

Mean Time Constant

0.6

(s)

0.4

Constant

0 0 0.2

Time

0.0

Normal Inc. TBI Inc. Normal Dec. TBI Dec.

(Green et al, 2010)

Dynamic Measurement Findings Dynamic Measurement Findings

Mean Peak Velocity

8 10

s)

4 6 8

elocity (D/s

2 4

Peak Ve Normal Inc. TBI Inc. Normal Dec. TBI Dec. (Green et al, submitted)

Dynamic Measurement Findings Dynamic Measurement Findings

Comparison of time constant and peak velocity mean values between the mTBI and normal groups (p<0 05) Parameter Direction of change in mTBI Normal vs. mTBI the mTBI and normal groups (p<0.05) group Time Constant Increase 259ms vs 384ms Time Constant Increase 259ms vs. 384ms Peak Velocity Decrease 8.0D/s vs. 5.6D/s (Adapted from Green et al, 2010)

Dynamic Measurement Findings

Mean Accommodative Response Level

Mean Initial Response Gain

Mean Accommodative Response Level

3 4

ve )

Mean Initial Response Gain

1.5

2 3

• mmodativ

sponse (D)

0 5 1.0

Gain

1

Acco Res

0.0 0.5

Normal 4D TBI 4D Normal 2D TBI 2D

Normal Inc. TBI Inc. Normal Dec. TBI Dec.

(Green et al, 2010)

Dynamic Measurement Findings

Mean Response Variability

0 20 0.15 0.20

(D)

0.10

ariability (

0.00 0.05

Va Normal 4D TBI 4D Normal 2D TBI 2D

(Green et al, 2010)

Dynamic Measurement Findings y g

Mean Monocular and Binocular A d ti Fli F ilit Accommodative Flipper Facility

20

m)

10 15

Rate (cpm

5

Flipper R

Normal OD Normal OS TBI OD TBI OS Normal OU TBI OU

(Green et al, 2010)

Dynamic Measurement Findings y g

Pre- and Post-Fatigue Binocular Accommodative Flipper Facility

20 22

Mean Pre- and Post-Fatigue Binocular Accommodative Flipper Facility

20

14 16 18

r Rate (cpm)

10 15

r Rate (cpm)

8 10 12

Flipper

5

Flipper

Pre-fatigue Post-fatigue

Pre-fatigue Post-fatigue

(Green et al, 2010)

Summary of Abnormal Findings from the SUNY Research Group the SUNY Research Group

• Static

Static

– Reduced amplitude of accommodation (66%) – Abnormally large phoria (64%) Abnormally large phoria (64%) – Abnormal NRA/PRA (50%) – Abnormal AC/A ratio (50%) ( )

• Dynamic

y

– Reduced peak velocity (100%) – Increased time constant (100%) ( ) – Exhibited accommodative fatigue (75%)

Clinical Implications p

• 5 of the 7 significant findings can be implemented

routinely in a clinic setting

• These abnormal findings are consistent with patient

symptoms symptoms

• Remediation can be performed with vision therapy,

l d/ i lenses, and/or prisms

• Provides insight into the affected neurological pathways

Provides insight into the affected neurological pathways

• Confirms the crucial role of the optometrist in the

di i d t t t f h ti t diagnosis and treatment of such patients

Future Directions

• Assess accommodative latency
• Testing with a ramp stimulus
• Testing with a ramp stimulus
• Assess steady-state accommodative response variability

y p y with power spectrum analysis

• Use age adjusted lens flipper powers
• Use age-adjusted lens flipper powers
• Assess effects of therapeutic interventions such as vision

p therapy, lenses, and/or prisms

– Clinical parameters – Laboratory static and dynamic parameters y y p – Brain imaging (e.g., DTI, fMRI) – Electrophysiological testing (e.g., VER)

Future Directions Future Directions

• Modeling using bioengineering control

Modeling using bioengineering control systems and neurophysiological approaches (MATLAB) approaches (MATLAB) T t th ABI h CVA

• Test other ABI groups such as CVA
• Test pediatric populations

Acknowledgments Acknowledgments

• We thank Drs. J. Choi-Lee, J. Cohen, L.

Lowell V Wren and Ms I Rosen for Lowell, V. Wren, and Ms. I. Rosen for providing study patients

• We thank Drs. S. Craig and D. Rutner for

their participation in the retrospective studies