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You may be surprised to find out that 90% of the traumatic brain injury patients and 86.7% of the stroke patients experience a vision problem that can be classified as oculomotor dysfunction.

These vision problems can result in double vision, blurry vision, difficulty following/tracking targets, oculomotor-related reading problems, and eye discomfort. Despite the presence of oculomotor dysfunction, many of these patients are still able to see 20/20 on the eye chart and have eyes that are deemed “healthy”.

Acquired brain injury can have significant effects on the visual system. These visual conditions can affect a person’s recovery, ability to return to work, and overall quality of life. Despite the importance of vision as one of our main sensory modalities, vision conditions following acquired brain injury remain under diagnosed and under-treated

A group of optometrists published a retrospective analysis entitled “Occurrence of Oculomotor Dysfunctions in Acquired Brain Injury” that showed just how many people experience vision problems following an acquired brain injury. For the purposes of their study, the researchers divided acquired brain injury patients into two groups: 1) Traumatic Brain Injury 2) Cerebrovascular Accident (Stroke).

Here is the breakdown of the vision conditions in the traumatic brain injury population:

• 56.3% were diagnosed with convergence insufficiency, a condition that can create headaches, eyestrain, and reduced fluency when reading
• 51.3% were diagnosed with deficits of saccades (ability to jump the eyes from one target to the next). This skill is essential for any activity that requires a person to quickly shift attention from one object to another. These may be small jumps that occur at the end of each line of text or large jumps that occur when watching multiple cars while driving.
• 41.1% were diagnosed with accommodative insufficiency, or reduced strength of eye focusing. This condition makes it extremely difficult for people of any age to keep text clear while reading.
• 25.6% were diagnosed with strabismus (eye turn) at near. An eye turn at near can cause double vision and can affect reading fluency.
• 6.9% were diagnosed with a cranial nerve palsy that affected eye alignment, eye movement, and the ability to move the eyes in a coordinated manner.

The vision conditions in the cerebrovascular accident (stoke) population were found to be:

• 56.7% were diagnosed with deficits of saccades (ability to jump the eyes from one target to the next). Deficits in this basic eye skill can inhibit a person's ability to regain their independence and pre-stroke lifestyle.
• 36.7% were diagnosed with convergence insufficiency. Convergence insufficiency can limit your ability to read, work on the computer, use your smart phone or other hand-held device, and any other near task.
• 36.7% were diagnosed with strabismus (eye turn) at far. When an eye turn is present while viewing objects beyond arm's length it results in double vision or suppression of one eye; ultimately limiting depth perception. This condition can make driving, watching television, or maintaining eye contact while talking with friends extremely difficult.
• 12.5% were diagnosed with accommodative infacility, or an inability for the eyes to change focus. This means that you will experience blurry vision any time you shift your eyes from distance to near or near to distance.
• 10% were diagnosed with a cranial nerve palsy that affected eye alignment, eye movement, and the ability to move the eyes in a coordinated manner.

 These vision problems have widespread affects on the person's life. Double vision, blurry vision, difficulty following/tracking targets, oculomotor-related reading problems, and eye discomfort directly impact quality of life. These vision dysfunctions can also negatively impact the other forms of rehabilitative therapy that is necessary for the person to recover. As the researchers put it, “If an appropriate vision diagnosis is not made, the patient’s visually based symptoms will persist and perhaps even become exacerbated.”

Fortunately many of these oculomotor dysfunctions can be effectively treated through vision therapy. Vision therapy administered under the guidance of an optometrist with residency training in binocular vision, neuro-optometry, and vision therapy can improve quality of life.

Reference: Ciuffreda, K. et al. "Occurrence of Oculomotor Dysfunctions in Acquired Brain Injury: A Retrospective Analysis." Optometry (2007).