Vision Deficits After TBI Vision Deficits After TBI Presented by:

Carl Garbus, O.D., FAAO

Learning ObjectivesLearning ObjectivesDescribe the incidence and prevalence of brain injury

Distinguish between acquired brain injury and traumatic brain injury

Identify basic brain structures and functions

Describe 2 main visual processes in the brain

Describe visual consequences of brain injury

Discuss assessments and interventions

Goals for the Presentation Goals for the Presentation Goals for the Presentation Goals for the Presentation Create awareness of what to look for in patients

who have had traumatic brain injury Stress the importance of having a neuro vision

evaluation for patients with traumatic brain injury and stroke

Know that neuro vision rehabilitation exists for patients with these conditions

Create awareness of what to look for in patients who have had traumatic brain injury

Stress the importance of having a neuro vision evaluation for patients with traumatic brain injury and stroke

Know that neuro vision rehabilitation exists for patients with these conditions

DefinitionsDefinitions

Acquired brain injury (ABI) –

An injury to the brain that has occurred after birth and is not hereditary, congenital or degenerative.

The term does not refer to brain injuries induced by birth trauma.

Causes of ABI

Traumatic brain injury (TBI)

Strokes

Tumors

Blood clots

Seizures

Causes of ABI

Toxic exposures (substance abuse, ingestion of lead, inhalation of agents)

Infections (encephalitis, meningitis)

Metabolic disorders (insulin shock, diabetic coma, liver and kidney disease)

Neurotoxic poisoning (airway obstruction, strangulation, carbon monoxide poisoning)

Lack of oxygen to the brain

DefinitionDefinitionCerebral Vascular Accident (CVA)Cerebral Vascular Accident (CVA)

Stroke - A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts. When that happens, part of the brain cannot get the blood (and oxygen) it needs, so it starts to die.

2 Types of Stroke

1. Ischemic strokes occur as a result of an obstruction within a blood vessel supplying blood to the brain. The underlying condition for this type of obstruction is the development of fatty deposits lining the vessel walls. This condition is called atherosclerosis. (87%)

2 Types of Stroke2. Hemorrhagic strokes result from a

weakened vessel that ruptures and bleeds into the surrounding brain. The blood accumulates and compresses the surrounding brain tissue. The two types of hemorrhagic strokes are intracerebral hemorrhage or subarachnoid hemorrhage. (13%)

DefinitionsDefinitionsTraumatic brain injury (TBI)

• An insult to the brain, not of a degenerative or congenital nature but caused by an external physical force,

That may produce a diminished or altered state of consciousness.

Causes of TBI:

Motor vehicle accidents - whiplash

Falls

Gunshot wounds

Work place injuries

Shaken baby syndrome

Child abuse

Sports injuries

Military actions

StatisticsStatistics

An estimated 1.7million people sustain a TBI annually in the US.

52,000 die

275,000 are hospitalized

1.365 million, nearly 80%, are treated and released from an emergency department.

Different ways brain can be damaged

Neck TraumaNeck TraumaNeck TraumaNeck Trauma

Whiplash: A simple whiplash can cause shearing of nerve

fibers in the brain stem This can occur from being rear ended by a car

driving moving at 15 miles an hour Disruption of fibers in the brainstem affects

oculomotor and binocular functions.

Whiplash: A simple whiplash can cause shearing of nerve

fibers in the brain stem This can occur from being rear ended by a car

driving moving at 15 miles an hour Disruption of fibers in the brainstem affects

oculomotor and binocular functions.

Whiplash InjuryWhiplash InjuryWhiplash InjuryWhiplash Injury

Basic brain structures Basic brain structures and functionsand functions

Lobes

" The eyes see only what the mind is ready to comprehend"

Henri Bergson

Brain and Brain and vision: vision: the connectionthe connection

Every lobe of the brain is involved in processing visual information.

To date, researchers have identified over 300 intracortical pathways linking 32 different cortical areas involved in vision function.

More than half of our gray matter and multiple subcortical areas are involved in processing vision.

There is more area of the brain dedicated to vision than to all the other senses combined.

The Visual BrainThe Visual Brain

Visual SystemVisual SystemGeneral OverviewGeneral Overview

Visual SystemVisual SystemGeneral OverviewGeneral Overview

70 % of all sensory processing in the entire body is directly affected by information coming from the two eyes

Optic Nerve- 1,000,000 nerve fibers per eye

There are several important pathways where the visual information travels

Brainstem – Cranial Nerves 8 of 12 relate to the visual system

70 % of all sensory processing in the entire body is directly affected by information coming from the two eyes

Optic Nerve- 1,000,000 nerve fibers per eye

There are several important pathways where the visual information travels

Brainstem – Cranial Nerves 8 of 12 relate to the visual system

Vision is a Bimodal Vision is a Bimodal SystemSystem

There are 2 main pathways that carry visual information from the eye to the brain.

Focal - the "what" system

Ambient - the "where system"

Designed to simultaneously process different types of visual information

Neither works in isolation of the other; both reinforce one another

Focal and Ambient SystemsFocal and Ambient SystemsFocal and Ambient SystemsFocal and Ambient Systems

Need to work in harmony

They are not isolated systems

A disconnect in the ambient system will cause problems with spatial orientation

Symptoms include: balance problems, bumping into things, difficulty navigating

Need to work in harmony

They are not isolated systems

A disconnect in the ambient system will cause problems with spatial orientation

Symptoms include: balance problems, bumping into things, difficulty navigating

Five Pillars of Five Pillars of FunctionFunction

Visual

Physical / Vestibular

Somatosensory

Cognition

Psychosocial

Why is vision rehabilitation so Why is vision rehabilitation so important following brain injury?important following brain injury?

Vision is our dominant sense; we are visual beings.

Vision is pervasive throughout our brain.

Vision is represented all over our body.

Vision influences and influenced by anything and everything - the way we think, say, or do.

Visual problems are among the most common consequences of TBI and or CVA but frequently not dealt within rehab model.

Visual Consequences of TBI: Visual Consequences of TBI: Post Trauma Vision Syndrome Post Trauma Vision Syndrome

(PTVS)(PTVS)A constellation of symptoms that evolves as secondary injury in TBI.

This syndrome is caused by a dysfunction of the ambient visual system and has the characteristics listed below:

Binocular coordination dysfunctions - double vision

Inability to perceive spatial relationships between objects

Difficulty fixating on object and following when it moves

Abnormal posture

Dizziness and balance problems

Poor visual memory

Visual consequences of TBI: Visual consequences of TBI: Post Trauma Vision Syndrome Post Trauma Vision Syndrome

(PTVS)(PTVS)

Poor concentration and visual attention

Difficulty with visually guided movements (bumping/tripping, knocking things over)

Light sensitivity / photophobia

Visual midline shift syndrome

Visual spatial difficulties

What are the functional What are the functional implications?implications?

Light sensitivityLight sensitivity

What are the functional implications?

Visual Field Defect

Sense of balance

Bump into things

Difficulty with eating

Slow reading

What are the functional implications?

Binocular Dysfunction

Difficulty judging distance or depth

Tendency to knock things over

Bump or trip over obstacles

Difficulty playing sports

What are the functional implications?

Visual information processing

Avoidance of crowded or busy places

Short memory

Forget familiar route

Slow to process

Visual Midline ShiftVisual Midline Shift

Visual Midline ShiftVisual Midline Shift

Mismatch between the perceived egocentric visual midline and the actual physical midlineCauses an expansion on one sideCauses a contraction on the opposite side

Mismatch between the perceived egocentric visual midline and the actual physical midlineCauses an expansion on one sideCauses a contraction on the opposite side

Visual Midline Shift SyndromeVisual Midline Shift SyndromeVisual Midline Shift SyndromeVisual Midline Shift SyndromeSigns and Symptoms

Floor may appear tilted

Walls and/or floor may appear to shift and move

Veering during mobility

Person leans away from the affected side

Feelings of imbalance or disorientation similar to vertigo

Signs and Symptoms

Floor may appear tilted

Walls and/or floor may appear to shift and move

Veering during mobility

Person leans away from the affected side

Feelings of imbalance or disorientation similar to vertigo

Visual Spatial InattentionVisual Spatial InattentionVisual Spatial InattentionVisual Spatial Inattention Individual with TBI or Stroke does not

process information on one side of their body Also known as Visual Neglect or Hemi-

neglect This is not a field defect but it can exist with

a field defect In severe cases the patient is not aware of a body part

Individual with TBI or Stroke does not process information on one side of their body

Also known as Visual Neglect or Hemi-neglect

This is not a field defect but it can exist with a field defect

In severe cases the patient is not aware of a body part

Visual Spatial Inattention CopyingVisual Spatial Inattention CopyingVisual Spatial Inattention CopyingVisual Spatial Inattention Copying

Star Cancellation

Cranial Nerve VIII – Cranial Nerve VIII – Auditory and Vestibular NerveAuditory and Vestibular Nerve

Cranial Nerve VIII – Cranial Nerve VIII – Auditory and Vestibular NerveAuditory and Vestibular Nerve

Nerve that transmits information for hearing and balance

Nerve that transmits information for hearing and balance

Vestibular FunctionVestibular FunctionVestibular FunctionVestibular FunctionThe visual system links up very closely with the vestibular system in the brainstem and midbrain

Vestibular –Ocular Reflex (VOR) is activated when there is a head movement, body movements or if the individual leans to one side

The visual system links up very closely with the vestibular system in the brainstem and midbrain

Vestibular –Ocular Reflex (VOR) is activated when there is a head movement, body movements or if the individual leans to one side

Vestibulo-Ocular ReflexVestibulo-Ocular ReflexVestibulo-Ocular ReflexVestibulo-Ocular Reflex Maintenance of fixation of the eyes with

head movements It is activated with horizontal and vertical

head movements This intricate system links the vestibular

system to the oculomotor system

Maintenance of fixation of the eyes with head movements

It is activated with horizontal and vertical head movements

This intricate system links the vestibular system to the oculomotor system

InterventionsInterventions

Patient education

Explain brain and vision relationship

Review individual's specific diagnosed eye condition in plain language

Why and how vision may be interfering or limiting daily functions.

Always include family members whenever possible

InterventionsInterventions

Compensation strategies

Relieve visual discomfort from eye strain and fatigue often leading to headaches.

Take care of those dry eyes!

Remediate glare and light sensitivity - very important!

Take frequent breaks from visually demanding tasks - 20/20/20 rule

Strategies for Double Vision Techniques

Consult with an optometrist or ophthalmologist who has experience with brain injury

Provide a translucent patch (not dark opaque patch)Spot patchSector patchBinasalsActive therapy prescribed by the eye care

practitioner can improve binocular function- Eye Stretches, Tactile Control, Spatial Localization, Brock String

InterventionsPrisms: bends light towards the base, which causes

the image to move in the opposite direction---- has implications to change spatial orientation and eye alignment

Lenses: optical correction of refractive conditions helps to locate objects in space and helps with visual comfort

Filters: blocks specific light frequencies that cause visual discomfort which can improve visual performance

SummaryConsult with an vision rehabilitation

doctor to collaborate about functional treatments

Consider visual conditions that can be treated such as light sensitivity, visual balance, visual midline shift and post trauma vision syndrome

Brainstem damage will have visual and vestibular consequences

Double vision is common problem that needs to be dealt with early

Neuro Optometric Rehabilitation Conference

24th Annual Multi-disciplinary ConferenceRenaissance HotelMay 14-17, 2015Denver, COWebsite www.nora.cc