Brain injury effects
Visual Disorders - Fact Sheet
Our vision is a sophisticated
complex of subsystems involving the flow and processing of
information to the brain. A brain injury can disrupt this visual
Individuals may have focusing problems, eye muscle coordination
deficits, changes in eyeglass prescription, and peripheral vision
changes. The type and extent of any visual problem depends on the
severity and location of the injury. Even when visual problems are
diagnosed there is often little vision rehabilitation offered. This
is unfortunate as treatment often provides relief from visual
Some symptoms to look for are:
- Headaches from visual tasks
- Blurred or double vision
- Sensitivity to light
- Inability to concentrate or focus
- Reading or comprehension difficulties
- Trouble judging distances
- Sore eyes
- Loss of visual field.
If you find it difficult to process visual information you may be
straining without realising it. A general sense of fatigue can
arise from visual problems.
Trauma can cause damage to parts of the brain responsible for
visual information processing. Even if the head does not hit
anything, whiplash can cause damage. Trauma may injure arteries,
stretch nerves or damage the vertebral column itself. It can also
create soft tissue damage that may cause eye muscle coordination
problems and other symptoms that patients experience.
Common Visual Problems
This can result when nerves or muscles of the eyelids are
affected. Symptoms are often relieved with the use of the correct
eye drops. In bad cases plugs placed in the tear ducts can solve
This condition may cause confusion and disorientation.
Individuals experiencing this condition are often given an eyepatch
to cover one eye although it reduces the field of vision and
interferes with daily function. Double vision can often be
prevented without an eye patch, through the use of prisms and
vision therapy. Prisms are used to shift objects in the field of
vision. They can correct problems between body image and perception
Loss of visual field
This loss is a common visual effect of Acquired Brain Injury.
There are many kinds but the most common is loss of half of the
field of vision in each eye. People frequently bump into objects,
and easily trip or fall over objects. They may be afraid of leaving
home and have difficulty reading. Therapy can help to detect
objects on their 'blind side' and use constant scanning to
compensate. Compensatory strategies are useful such as always
aligning oneself to objects or people so they are centred in the
remaining visual field. Prisms and mirror devices are often helpful
in cases of visual field loss. Tiny mirrors attached to glasses can
expand visual field awareness. If there is some remaining vision,
stimulatory exercises can be used to increase light sensitivity and
regain some lost function.
These may arise from blurred or double vision, jerky eye
movements, or visual field loss. Treatment can involve aids such as
prisms or using a typoscope to focus on individual sentences. After
injury, it can be hard to focus on a page due to nerve damage that
affects the eye's refocussing. Bifocal glasses can compensate. Eye
movements can be impaired by Acquired Brain Injury which may
prevent smooth reading along the page. Therapists may be able to
rebuild reading skills to reduce problems such as this.
Following a brain injury some people have a normal field of view
but can't read print or watch television with conventional glasses
because of low vision. Low vision aids include telescopic lenses
for distance vision and a range of magnifying aids for reading and
other fine tasks.
Light sensitivity varies from person to person. Some have no
trouble but others find bright light painful. Solutions may include
tinted eyewear, or amber filters. Sometimes treatment for other
problems will reduce photosensitivity.
Visual hallucinations may be formed objects such as a person or
figure, or may be unformed such as flashes of lights, stars or
Impaired visual memory
Memory is often impaired after stroke or head injury. In rare
cases very specific types of memory processing are impaired. A
person may no longer be able to recognise faces, objects or
After a brain injury some people experience a natural recovery,
usually within six months. This recovery can be assisted with use
of any necessary prescription lenses. Some people will not recover
naturally but may do so with vision therapy. Studies show that
vision therapy hastens natural recovery as well.
A clinician skilled in both low vision and brain injury will
understand the interaction of these problems and be able to make a
plan to rehabilitate the visual system. After evaluation,
examination and consultation, a clinician will determine how a
person processes information after an injury and where that
person's strengths and weaknesses lie. They provide treatment
designed for each individual and frequently incorporate
combinations of lenses, prisms, low vision aids, and vision therapy
activities. The road to recovery needs the teamwork of many doctors
and therapists with time and patience throughout the rehabilitative
References and further information
A list of optometrists and opthalmologists can be obtained by
ringing the Optometrists Association in your State or by visiting
the Optometrists Association of Australia at www.optometrists.asn.au.
For more in-depth fact sheets on visual difficulties, try Vision
Australia's Fact Sheets.