visual dysfunction for educational professionals 1 › ... › 16 › brainsteps_vision2.pdf ·...

10/20/14

Property of Nathan Steinhafel, MS, OD, FAAO. Do not distribute without permission 1

Visual Dysfunction Following Concussion: Concepts for the Educational Professional November 5, 2014 BrainSTEPS Nathan Steinhafel, MS, OD, FAAO. Pediatric & Neuro-Optometrist

Nothing to Disclose �  I have no financial interest in the following

companies, products, or research groups discussed.

Epidemiology �  1.6 – 3.8 million concussion (mTBI) per year.

�  Estimated 85% go undiagnosed.

�  World Health organization estimates that 70-90% of traumatic brain injuries are concussion.

�  According to the CDC, the most common causes of TBI in the civilian population are: �  a) Falls/Sports: 35.2% �  b) Unknown/Other: 21% �  c) Motor Vehicle-Traffic: 17.3% �  d) Struck By/Against: 16.5% �  e) Assault: 10%

�  Estimated 1/3 of patients will have visual dysfunction

�  www.cdc.gov/TraumaticBrainInjury/causes.html

10/20/14


Persistent Post concussion syndrome

�  Many different criteria

�  ICD-10: �  3/8 symptoms within 4 wks

�  DSM-IV �  3/3 of the symptoms �  >3 months

�  Diagnostic and Statistical Manual of Mental Disorders. Fourth Edition Heitger MH et al.

Brain 2009: �  3 months duration of three or more of following:

�  Fatigue �  Disordered sleep �  Irritability / aggressiveness �  Anxiety / depression �  Personality changes / apathy �  Impaired attention / memory �  Impairment of eye skills �  Impaired balance

Symptom ICD-‐10 DSM-‐IV Headache x x Dizziness x x FaGgue x x Irritability x x Sleep problems x x ConcentraGon difficulGes x Memory difficulGes x Cannot handle stress/alcohol/emoGon x Mood,anxiety, depression x Personality changes x Apathy x

Goals and Objectives �  Understanding the prevalence and mélange

of visual symptoms as a result of concussion. �  Identify the most common visual system

impairments occurring after mild traumatic brain injury.

�  Discuss screening and assessment techniques for identifying visual system impairment for the school nurse, therapist, or allied health professional who treat concussion.

�  Elucidate the level of visual impairments in the classroom, employ strategies for the teacher, and the use vision therapies performed at home or in office for the therapist.

Giza CC, et al. J Athl Train 2001

488 THE NEUROSCIENTIST Axonal Damage in Traumatic Brain Injury

Fig. 5. Illustration of the structure of neurofilaments (NFs), the major structural component of the axonal cytoskeleton. The roddomains of NF subtype proteins run parallel in the core of the NF. Whereas NF-light (white) has only a rod domain, the sidearmdomains of NF-medium (red) and NF-heavy (blue) stand out from the NF core creating a physical spacing between neighboring NFs. Itis proposed that the sidearms may be cleaved off or may collapse during traumatic axonal injury, inducing compaction of the NFs inthe axons impeding axonal transport.

A B

C D

Fig. 6. Electron micrographs of axons of the optic nerve. A, Longitudinal section illustrating the interneurofilament spacing of a normalaxon. B, Following stretch injury, compaction of the neurofilaments is observed. C, Transverse section of a normal axon demonstratingmicrotubules (arrow). Following stretch injury, there is a loss of microtubules (arrow). (Reprinted with permission from ref. 46.)Electron micrographs of axons of the optic nerve.

A. Longitudinal section illustrating the interneurofilament spacing of a normal axon. B. Following stretch injury, compaction of the neurofilaments is observed. C.Transverse section of a normal axon demonstrating microtubules (arrow). D. Following stretch injury, there is a loss of microtubules (arrow). Maxwell et. al.1997. A mechanistic analysis of non disruptive axonal injury: a review. J Neurotrauma.

10/20/14


�  A. Elongated varicose swellings of damaged axons are shown with swollen regions encompassing several hun- dred micrometers but no clearly identifiable region of disconnection.

Smith et. al. 2000. Axonal Damage in Traumatic Brain Injury. Neuroscientist.

�  B. Axonal bulbs are shown, demonstrating the characteristic discrete region of swelling at the terminal stump of disconnected axons. Remarkably, these axonal bulbs are preceded by axonal shafts of relatively normal diameters (bar = 50μm).

Smith et. al. 2000. Axonal Damage in Traumatic Brain Injury. Neuroscientist.

Eye & TBI Research… �  Ciuffreda,et al. K. 2007: Accommodative and vergence deficits were

most common in the mTBI subgroup, whereas strabismus and CN palsy were most common in the CVA subgroup.

�  Brahm et. al. 2009: Visual dysfunctions (convergence, accommodative, and oculomotor dysfunction) were common inpatient and out populations who suffered blast and non-blast related concussion. Visual field defects were more often associated with blast than non-blast events.

�  Capo-Aponte et. al. 2012: The most common mTBI-induced visual dysfunctions were associated with near oculomotor deficits �  1. Large exophoria, �  2. Decreased fusion ranges, �  3. Receded near point of convergence, �  4. Defective pursuit and saccadic eye movements, �  5. Decreased amplitude of accommodation, and monocular accommodative

facility. �  6. Reduced reading speed and comprehension. �  7. Increased Convergence Insufficiency Symptom Survey score. �  8. Photosensitivity.

� 

Visual symptoms � Headaches � Blurred vision � Double vision � Light sensitivity �  Illusions of movement � Poor eye tracking � Eye fatigue � Vertigo

10/20/14


Visual induced Headaches � Frontal or temporal in nature � Worse as the day progresses � Worse with visual activity

�  Reading �  Computer �  Motion �  Visual movement �  Taking notes from the board �  Light induced

Common Visual Sequelae found with mTBI � Photophobia/Photopsia � Convergence Insufficiency � Accommodative Dysfunction � Ocular Motor Dysfunction � Vestibular Ocular Reflex Dysfunction

I. Photophobia �  Definition: discomfort to light exposure. 5-20%

of the population (w/o concussion). Much higher % with concussion.

�  Classroom: Students will find it difficult to focus under varying environments of unnatural light: �  Fluorescent lighting �  CFL �  LED �  Computer screens �  Smart boards

Fluorescence � Rapid flicker frequency, low wavelength

or high intensity of fluorescence can trigger or worsen migraines or chronic post traumatic headaches.

10/20/14


Fluorescence �  Fluorescence have the potential aggravate

patients suffering: �  Peripheral vestibular dysfunction who have

vertigo. �  Epilepsy (light induced) �  Anxiety �  Autism �  Dyslexia �  Headaches �  Eye strain

Emerging and Newly Identified Health Risks. Director-General for Health and Consumers, European Commission. 2008. pp. 26–27. Retrieved 2009-08-31.

Modifications � Avoidance. Sitting closer to natural light

sources.

Modifications �  ‘Fluorescent lighting filters’

Smart/Board Promethium Boards � Adjusting the light settings on your smart

or Promethium board. �  Dimmer �  Grayscale

10/20/14


Modifications � Nurses office

Sunglasses �  “Different wavelengths affect an individual's comfort

level. Some studies have indicated that migraine sufferers experience more discomfort with blue-wavelength light.” �  http://uuhsc.utah.edu/MoranEyeCenter/patientcare/

FL-41_history.html

�  Tints �  Gray (over all light sensitivity) �  Rose (Fluorescence, LED, Computer monitors) �  Amber (to improve contrast sensitivity) �  FL-41 (Blocks low wavelength light) �  Blue Blockers (Blocks low wavelength light)

II. Convergence Insufficiency � Definition: Sensory and neuromuscular anomaly of

the binocular vision system, characterized by an inability of the eyes to turn towards each other or sustain convergence while reading. Also, when there is a tendency of the eyes to deviate outward (exophoria). Not age dependent.

� Non-TBI Cohort: prevalence up to 6% in general population. Much greater in mTBI cases.

¨  Ciuffreda KJ, et. al. 2008 Vision therapy for oculomotor dysfunctions in acquired brain injury: a retrospective analysis. Optometry.

¨  Convergence Insufficiency Treatment Trial (CITT) Study, Group 2008. The convergence insuffiency treatment trial: design, methods, and baseline data. Ophthalmic epidemiology.

10/20/14


Convergence Insufficiency � Classroom symptoms may include:

�  Double vision while reading �  Blurred vision when reading or on the

computer �  Eye strain after reading for prolonged

periods of time �  Headaches that are located (but not

limited to) the frontal and temporal lobe region.

Convergence Insufficiency � Direct findings

�  1. Decrease near point of convergence (>6cm)

�  2. Exophoria greater at near than distance � Normal: orthophoria to 4 XP (±2) � Abnormal: >6XP

�  3. Abnormal: Poor compensating fusional convergence skills

� Testing �  1. Using a single target 3 sizes above threshold near visual

acuity. �  i.e if they are capable of seeing 20/20 print use a 20/40

single target – newspaper sized print. �  2. Start at ~50cm and slowly bring it to the tip of their nose. �  3. “I’m going to move this target toward you. Tell me when

it’s double”. Regardless if it’s blurry. �  4. NPC= “Double” or when one eye deviates = NPC (break) �  5. “I’m going to pull it back away from you. Tell me when

you regain a single image.” (recovery).

�  Difference between break/recovery: 3-4 cm.

Convergence Insufficiency

10/20/14


Convergence Insufficiency �  Treatment options

�  CI: � Vision therapy � Prism

�  XP � Vision therapy � Prism, if the magnitude of the exophoria is larger �  Strabismus surgery if exo deviation is significant

>20^

�  Convergence Insufficiency Treatment Trial Study Group. Randomized Clinical Trial of Treatments for Symptomatic Convergence Insufficiency in Children. Arch Ophthalmol. Oct 2008;Vol 126 (No. 10).

�  Scheiman M et. al. Non-surgical interventions for convergence insufficiency. Cochrane Database Syst Rev. 2011.

Vision Rehabilitation Program

Convergence Insufficiency � Strategies for the classroom:

�  Avoid or lessen near working tasks � eg. 15-20 min. reading with 10 min. breaks

�  Limit or minimize time on the computer, �  Extra time on tests

� Eg. 30 minutes extra one on one outside of the classroom.

�  Reduced reading assignments �  Class notes �  Using a book stand

10/20/14


III. Accommodative Insufficiency �  Definition: Inability of the eyes to focus

properly at a near target. Amplitude of accommodation is lower than expected for the patient’s age.

�  This is the most common accommodative disorder.

�  80% of individuals who have CI will also have AI.

�  Direct findings: �  Decreased monocular amplitude of

accommodation

�  Scheiman. 2008. Clical management of Binocular Vision: Heterophoric, Accommodative , and eye movement disorders.

Accommodative Disorder �  General symptoms

�  Blurry vision at near �  Blurry vision at near with spasm of accommodation or

after periods of reading �  Excessive blinking �  Eye fatigue after reading

�  Non-TBI Cohort Studies: Prevalance: 8-17% in the of general population <15 years of age (school screenings).

�  Helveston et. al. 1985 �  Walters. 1984 �  Rouse et. al. 1989 �  Borsting et. al. 1999

Accommodative Insufficiency �  Signs

�  Decreased amplitude of accommodation �  Age dependent �  Measured in diopters �  D = 1/M

�  i.e. 10cm = 0.10 M � D = 10 D = 1/0.10

�  Hofstetters Formula � Normal AMP (D)= (15 – (0.25)Age) – 1)

�  General screening rule: <30 years of age <15cm.

�  Treatment �  Vision therapy �  Reading glasses or bifocals*.

Age

Minimum distance (Cm)

Minimum AMP (D)

6 8 12.5 8 8 12 10 9 11.5 12 9 11 14 10 10.5 16 10 10 18 11 9.5 20 11 9 22 12 8.5 24 13 8 26 13 7.5 28 14 7 30 15 6.5 32 17 6 34 18 5.5 36 20 5 38 22 4.5 40 25 4 42 29 3.5 44 33 3 46 40 2.5

10/20/14


�  Testing �  Monocular test! �  Use newspaper sized print if they can see 20/20

at near. �  Measured in cm, convert to D. �  Bring towards patient until they report sustained

“blur”. �  Compared to age related normative values. �  Must be wearing glasses if they have them.

Accommodative Disorder

Other Accommodative Disorders (not limited to)

�  A. Ill-Sustained Accommodation �  A form of AI where function deteriorates with long durations

of reading.

�  B. Accommodative Infacility �  The accommodative system is slow at making change. �  This is the second most common accommodative

condition. �  Symptoms:

� Difficulty copying from the board to notes at school. �  Treatment:

� Bifocals � Vision therapy

Vision Therapy Program Modifications � Classroom strategies

�  Reading avoidance �  Reduced reading or computer work �  Frequent breaks �  Extra time on tests �  Wearing habitually prescribed reading

glasses.

10/20/14


IV. Ocular motor dysfunction �  Definition: the absence or defect of controlled

and voluntary eye movements such as saccadic and pursuit movement.

�  General symptoms: �  Jerky eye movement �  Losing their place while reading. �  Slowed or re-reading �  Blurred vision �  Eye pain or discomfort �  Moves head excessively when scanning

environment or when reading �  Uses finger or marker to maintain place �  Moving print.

Reading difficulties

Ocular motor dysfunction �  Signs

�  Hypometric or hypermetric saccadic activity �  Slow or latency with pursuit movement; or may elicit excessive head

movement. �  Testing PT/Nurse:

�  Finger saccades �  Finger pursuits �  EOM screening for full range of motion

�  Testing optometry/ophthalmology �  EOMs �  Saccades/Pursuits �  Monocular Ductions �  Developmental Eye Movement Test (DEM):

�  Controls for automaticity – ability to cognitively rapid number name. �  <13 y.o. age related norms

�  King-Devick �  All ages

�  Pierce Test

Developmental Eye Movement test (DEM)

10/20/14


King-Devick Modifications/Treatment � Classroom strategies:

�  Using a rule as a guide �  Extra time on tests �  Reduced reading assignments �  Larger print

� Treatments: �  Reading programs �  Vision therapy

Vision Therapy Program

10/20/14


V. Vestibular Ocular Reflex (VOR) Dysfunction � Definition: a reflex eye movement that

fixates an image on the retina during head rotation by producing an eye movement in the direction opposite to head movement.

VOR Dysfunction �  Students with an abnormal

VOR function may experience: �  Dizziness �  Nausea �  Trouble viewing movement �  Nystagmus [shaky eye] �  Poor fixation �  Balance trouble �  Decreased mobility in

crowded places [hallways, cafeteria, buses, playground].

Modifications �  Accommodation for school:

�  Limit board to desk copying. Note taking service or teacher notes.

�  Limit time exposed in the hallways or cafeteria �  Early release from class �  Proper placement in the class to minimize head

rotation and visual distraction �  No gym participation �  Encourage parents to pick them up from school

or limited time riding the bus.

10/20/14


Vision to Vestibular interaction �  Is it Vision or Vestibular? �  Because normal vestibular system function is

predicated on normal ocular motor function, dysfunction in the visual system may mimic or potentiate the symptoms of vestibular pathology.

�  Referrals to the right team: �  Physical therapist �  Pediatric or Neuro Optometry/Ophthalmology �  Internal Medicine �  Neuro psychology

Screening �  Concepts for: School Nurse, Athletic Trainer, or

allied health professionals who evaluation and screen for concussion.

�  Convergence: Near point of convergence (Normal >6cm)

�  Accommodation: Amplitude of accommodation (Normal >15cm; <30 y.o.)

�  Ocular motor: Smooth and accurate pursuits and saccades, respectively. King-Devick.

�  VOR: Awareness of common clinical symptoms [Dizziness, Nausea, balance].

Bibliography �  Capo-Aponte JE, Urosevich TG, Temme LA, Tarbett AK, Sanghera NK. Visual

dysfunctions and symptoms during the subacute stage of blast-induced mild traumatic brain injury. Mil Med. Jul 2012;177(7):804- 813. Kapoor N, Ciuffreda KJ, Han Y. Oculomotor rehabilitation in acquired brain injury: a case series. Arch Phys Med Rehabil. Oct 2004;85(10):1667-1678.

�  Kraus MF, Little DM, Donnell AJ, Reilly JL, Simonian N, Sweeney JA. Oculomotor function in chronic traumatic brain injury. Cogn Behav Neurol. Sep 2007;20(3):170-17.

�  Ciuffreda KJ, Kapoor N, Rutner D, Suchoff IB, Han ME, Craig S. Occurrence of oculomotor dysfunctions in acquired brain injury: a retrospective analysis. Optometry. Apr 2007;78(4):155-161.

�  Ciuffreda KJ, Rutner D, Kapoor N, Suchoff IB, Craig S, Han ME. Vision therapy for oculomotor dysfunctions in acquired brain injury: a retrospective analysis. Optometry. Jan 2008;79(1):18-22.

�  Brahm KD, Wilgenburg HM, Kirby J, Ingalla S, Chang CY, Goodrich GL. Visual impairment and dysfunction in combat-injured servicemembers with traumatic brain injury. Optom Vis Sci. Jul 2009;86(7):817-825.

�  Scheiman M, Gwiazda J, Li T. Non-surgical interventions for convergence insufficiency. Cochrane Database Syst Rev. 2011 Mar 16;(3):CD006768.

�  Convergence Insufficiency Treatment Trial Study Group. Randomized Clinical Trial of Treatments for Symptomatic Convergence Insufficiency in Children. Arch Ophthalmol. Oct 2008;Vol 126 (No. 10).

�  Ciuffreda KJ. Ludlam DP. Kapoor N. Clinical oculomotor training in traumatic brain injury. Optom Vis Dev 2009;40:16-23.

�  http://uuhsc.utah.edu/MoranEyeCenter/patientcare/FL-41_history.html

Thank You! � Contact information:

�  Nathan Steinhafel, MS, OD, FAAO

�  [email protected]

visual dysfunction for educational professionals 1 › ... › 16 › brainsteps_vision2.pdf ·...

Documents