Concussion Treatment: Convergence Insufficiency
Today’s guest post on concussion treatment comes from Shaun Logan, DPT. Shaun original wrote a 2-part article here on the Risk and Recovery Process Following Concussions in Sports and The Role of Rehabilitation Following Concussions. In this new post, Shaun shares more thoughts on the treatment of concussions, specifically regarding convergence insufficiency.
Concussion Treatment: Convergence Insufficiency
A concussion can affect many systems of the body, including but not limited to the visual, musculoskeletal, vestibular, cardiovascular, central nervous, and peripheral nervous systems. The most common issues that tend to arise and be addressed at physical therapy include musculoskeletal issues to the cervical spine and head, oculomotor function, vestibular reflexes, positional habituation and balance, coordination, physical exertion and activity progression with change of direction, and attention issues.
However, the system that seems to be affected more often and consistently than the others is the visual system.
Impairment of the Visual System Following Concussions
People with a concussion often report an inability to focus with their eyes, blurriness, double vision, losing their place while reading, eye pain, headaches, dizziness, difficulty with reading comprehension, fatigue, and poor concentration or easily distracted. For example, while trying to read or perform schoolwork, many people will start to have blurriness and eye-strain that leads to headaches which then causes frustration, decreased reading comprehension, decreased attention, and decreased ability to perform their work.
All of the aforementioned issues can be tied back to one, often over-looked issue: convergence insufficiency.
Before I delve further into convergence insufficiency, lets quickly define some related visual components:
- Accommodation is the ability of the eye to make adjustments of the lens to focus on objects at various distances.
- Vergence is movement of the eyes synchronously and symmetrically in opposite directions.
- Divergence is the ability of the eyes to move laterally, towards the ears, to be able to see farther targets.
- Convergence is the ability of the eyes to move medially, towards the nose, which allow for single vision of closer objects – the ability to cross your eyes, therefor Convergence insufficiency is the inability to do so. Accommodation and vergence work synchronously to be able to focus clearly and quickly on objects at different distances.
For the rest of the article I will only refer to convergence or convergence insufficiency since this is the most common issue and is what should be focused on at physical therapy. But, keep in mind someone can have dysfunction or insufficiency of accommodation, convergence, divergence, and/or other areas of visual system that are beyond the scope of an athletic trainer and physical therapist.
Vergence is so important because rapid, accurate eye movements are necessary to fixate and stabilize an image in the eye, which is imperative during body movement. It takes a complex, coordinated system to get the fixated vision and then change quickly to a new target. “The eyes and the neck work together to localize and stabilize an image by optokinetic and vestibular reflexes. These reflexes provide a platform from which voluntary eye movements are executed.” 
Convergence insufficiency is a common eye neuromuscular coordination issue found in the general population. It is also very common for convergence insufficiency to occur with the onset of a concussion, or other brain injuries. The neuromuscular connection to the extraocular muscles is not working properly, so the muscles do not activate well, and basically lose efficiency, “endurance” and “strength”. Due to injury, greater effort is required to move the eyes medially, which causes eye-strain and pain, just like with any other muscle injury.
Symptoms typically worsen with reading, computer use, or a visually demanding environment. Keep in mind, symptoms may take extended periods of time to onset.
Common symptoms of convergence insufficiency include blurred vision, diplopia (double vision), near sighted discomfort, frontal headaches, pulling sensation in eyes, sleepiness, loss of concentration, nausea, eye discomfort, and general fatigue. All of which are common symptoms of a concussion.
Almost every athlete that I see with a concussion has a convergence insufficiency. Some are worse than others, but I almost always provide convergence exercises as a home exercise program following their initial evaluation.
No matter what, if they are coming to physical therapy for a concussion or post-concussion syndrome, they need retraining of the eyes. How much? That depends on the individual.
Examination for Convergence Insufficiency
Unfortunately, convergence is often over-looked. If this is not corrected, the athlete will continue with symptoms. Working on convergence can be a quick and easy way for someone with a concussion to start to feel better quickly. It seems to work especially well, and quickly, with athletes who sustained recent concussions, helping them become symptom-free more quickly.
I like to get athletes started with concussion rehab as soon as possible. In my opinion, complete rest should not be prescribed for everyone. Rest following onset of a concussion is completely relative – relative to the individual, their symptoms, their response to stimulus, etc. Treatment is completely dependent on individual symptoms.
It is common for me to see athletes who were doing great on the surface: no symptoms with school work, feeling great, feeling “normal”, but their symptoms returned when they were progressing through return-to-play programs, lifting weights or performing cutting/quick change of direction movements. Their underlying issue that was never addressed is overwhelmingly convergence. Convergence insufficiency is always problematic with long-term post-concussion syndrome (PCS), but there are also so many other issues involved at that point. Those with PCS are likely to need vision therapy with an optometrist. As with every treatment, convergence is individualized.
As the physical therapist or athletic trainer, we want to observe how the eyes move and take a thorough subjective history. A big portion of determining convergence insufficiency is through the history. Some individuals may pass the clinical test, showing “within-normal-limits”, however they still have symptoms. Find out what activities cause onset of symptoms, how long it takes for onset of symptoms with activities, such as reading, difficulty focusing eyes while taking notes (changing from far to near), quick change of direction, where headaches are located, frequency and length of headaches, etc.
Clinically, I test convergence with taking a pen, starting about 2 feet away from the client’s face, and slowly move the pen towards their nose. Instruct the client to focus on the pen and tell me when, or if, they start see 2 of the pen. Also, ask when the pen starts to get blurry, if they had eye pain or strain, dizziness, headaches, etc. (This examination actually tests convergence and accommodation, and is not terribly accurate but gives me a sense of where to start.)
“Normal” convergence is starting to get diplopia within 4-6 cm from the nose – meaning, they are able to move both eyes medially to focus on the target, keeping it as one, up until that point. For those with concussion, it is common to get diplopia at 15-20 cm or not at all.
Here is an example of normal convergence in a non-concussed healthy collegiate student-athlete:
Other signs to look for include:
- Do the eyes move easily medially?
- Do both eyes move the same, symmetrically?
- Does one eye have more difficulty converging?
- Does one eye float laterally?
Here is a 15 year old student-athlete with PCS. Initial head injury occurred in July 2013 when he was hit in the face by someone else’s head while playing capture the flag. He then had poor management and subsequent complications. For this video, he was instructed to focus his eyes on the pen, holding for 3-5 seconds then focus his eyes beyond the pen. Just watch how his eyes react to this, and listen closely to his response at the end of the clip. He has been referred to vision therapy, while continuing with physical therapy.
After measuring where they start to get diplopia, I always watch the target move as close as I can to the nose to assess further; as signs and symptoms are often noted the closer the target is to the eyes. Though normal convergence is considered between 4-6 cm from the nose, the client/athlete should not have signs or symptoms (other than diplopia and blurriness) with the target being brought in all the way to the nose. I think it is good to assume that almost all athletes with a concussion have some form of convergence insufficiency, and should be given convergence exercises as part of their home exercise program and treatment. Each diagnosis and treatment still has to be individualized based on his or her limitations and symptoms.
If their eyes, and symptoms, do not improve with simple convergence exercises (examples below) then they should be referred to an optometrist that specializes in visual therapy for further assessment and treatment.
Also, do not forget that the eyes and neck work together to find and fixate images so that our bodies can adapt and react to perform other voluntary movements. The musculature of the cervical spine and head can not be ignored. Insufficient performance and restrictions in these muscles is likely related to symptoms such as frontal headaches and dizziness.
Again, I recommend starting rehab right away. Do not wait. In my experience, results are better. A good physical therapist will be able to base treatment off of the patient’s symptoms.
Treatment for Convergence Insufficiency Following a Concussion
There are a few treatments that I tend to offer for people with convergence insufficiency. These include:
Focus eyes on static target (target in focus, everything else blurry), then focus eyes on everything beyond the target (everything else in focus, target blurry) — Target can be something simple like their hand or a pen.
Brock String Training
- Gallaway, M. (2014). Convergence Insufficiency. Retrieved from http://www.drgallaway.com/vision-and-learning/convergence-insuffiency/
- Cooper, J.S, et al. (December, 2010). Care of the Patient with Accommodative and Vergence Dysfucntion; Optometric Clinical Practice Guideline. Retrieved from http://www.aoa.org/documents/CPG-18.pdf
About the Author
Shaun Logan is a physical therapist located in the Philadelphia area that specializes in sports/orthopedics and concussion rehab. He earned his undergraduate degree from Penn State in Kinesiology and Doctor of PT degree from Drexel University. He currently works at The Training Room, located within Velocity Sports Performance of South Jersey, where he treats athletes of all ages and skill levels – from pediatric to professional to the active adult. He is also an assistant lab instructor for the Drexel University DPT program. Shaun works closely with the Rothman Institute’s concussion specialist, as well as a concussion rehab consultant for the Philadelphia Phillies. He believes in a more aggressive, but smart and calculated, treatment approach to concussions. In general, his treatment style for sports/orthopedics is based on movement, performance and educating clients how to move more efficiently.