Post Trauma Vision Syndrome (PTVS)
What is post trauma vision syndrome?
Common visual pathological conditions of PTVS include:
- oculomotor (eye tracking) dysfunction
- binocular dysfunction (eye teaming)
- accommodative dysfunctions (eye focusing)
Symptoms of post trauma vision syndrome
Common symptoms of PTVS include:
- blurred vision
- double vision (diplopia)
- difficulty reading or using a computer
- visual movement – a sensation that your world is moving
- feeling of constant motion
- balance issues and dizziness
- light sensitivity (photophobia)
- sensitivity to visual information – for example, feeling overwhelmed by being in a small group of people or in the aisles of a grocery store
- decreased or slowed processing and difficulty with memory
Diagnosis of post-traumatic vision syndrome
A regular eye exam takes about 20 to 30 minutes to determine if you need a pair of glasses. Extensive functional vision tests by a developmental optometrist can detect post-traumatic vision syndrome and other functional vision issues.
Visual rehabilitation therapy
Some functional visual problems cannot be treated effectively with just a regular eye exam and a new eyeglass prescription. An individualized program of visual rehabilitation therapy, however, can be designed to enhance the brain’s ability to control how the eyes work together.
Visual rehabilitation therapy sessions include strategies to:
- strengthen the visual system
- help restore balance between the visual and vestibular systems
- help patients return to work and other activities
Developmental optometrists are specialists in providing visual rehabilitation therapy. While 20% of the patients they see need no further treatment beyond a bit of prism to treat eye teaming issues or visual midline shift syndrome, prescription in lenses, and tinted lenses, the remaining 80% need active therapy.
Even patients who have been suffering with dizziness as a result of functional visual problems for a number of years can get back to their regular lives after visual rehabilitation. The process is sped up when the patient does visual and vestibular rehabilitation therapy concurrently.
Eye tracking problems
Eye tracking problems (saccadic eye movements) are common after concussion. Saccades are rapid eye movements that allow the eye to “jump” from one fixed target to another. Eye saccades do not involve the vestibular system. They involve the use of brainstem nuclei that control eye muscles.
Research shows that just over 51% of patients with concussion will have a problem with eye tracking. People with poor tracking become visually overwhelmed by peripheral information. If they walk down the aisle of a busy grocery store, for example, their eyes aren’t sure where to look. Their vision system basically shuts down.
Symptoms of eye tracking problems include:
- skipping, re-reading or substituting words while reading
- difficulty reading
- avoiding near tasks
- poor attention
- decreased comprehension while reading
Diagnosis of eye tracking problems
As part of extensive vision testing, you are connected infrared goggles while you read a brief story. The goggles measure how your eyes move across the page. The goggles are connected to a program that computes the grade level of your reading. The test measures:
- how many times you regress
- how many words you take in per minute
- average span of recognition - that is, how many words you take in before you stop and pause
Treatment of eye tracking problems
No special eyeglass prescription exists to solve eye-tracking problems. However, developmental optometrists can help patients improve eye tracking by working on what is referred to as central and peripheral processing. Patients are taught exercises that are done at home between office visits.
Eye teaming problems
Developmental optometrists spend time measuring how your eyes come together and move apart, both when looking close up and at a distance. This is referred to as eye teaming.
When your eyes are working together properly, they exhibit vergence. Vergence is the simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision.
Up to 56% of concussion patients have some type of eye teaming dysfunction. Many dizzy patients have problems with eye teaming.
If an object is up close, they frequently are not able to cross their eyes or bring them together. If an object is far away, their eyes often come together short of the target.
Symptoms of eye teaming problems commonly include:
- double vision
- difficulty reading
- words moving into each other
- covering an eye when reading
- poor ability to look near to far or far to near quickly
Treatment of eye teaming problems
Eye focusing problems
People with “normal” vision are able to rapidly bring objects of visual interest into sharp focus without even thinking about it. For those with eye focusing problems (accommodative dysfunction) the eyes and vision system do not focus properly. Research suggests that up to 41% of patients have deficits in accommodation after concussion. Many children and adults are misdiagnosed with Attention Deficit Disorder (ADD) because they cannot eye focus – if things appear blurry, they simply walk away.
Symptoms of focusing problems include:
- intermittent blurred vision at distance, near or both distances
- visual problems focusing on near tasks, or changing focus from near to far, or far to near
- headaches, typically frontal or temporal
- pain around the eyes during visual activities
- reading problems, such as difficulty concentrating and having to re-read for concentration
Testing for focusing problems is part of complete vision and includes:
- taking detailed measurements of how the eyes are teaming at a distance and close up
- observing horizontal and vertical eye movements
- evaluating how your eye focusing compares with age norms – most importantly, after therapy, the doctor can see how your focusing has changed
Treatment for focusing problems
Improved focusing ability can usually be effectively developed with a program of vision therapy devised by a developmental optometrist. Glasses for near use only, or in special bifocal form, may be used in some cases to reduce symptoms however they don’t actually correct the problem.
Johal S. Balance and dizziness: the visual connection. 2016. Talk presented to Balance & Dizziness Canada.