What is Convergence Insufficiency? Convergence insufficiency is a problem with the eye muscles working together (aka: “eye teaming”) to view near objects. One or both eyes can have a tendency to move outward when reading or viewing something up close. Convergence insufficiency can also be present without a concussion; in fact, approximately 5% of the healthy population has convergence insufficiency and may not be aware of this diagnosis.
Why does convergence insufficiency happen after concussion? A concussion injures brain cells (neurons). The area of the brain that is injured depends on where and how the injury occurs; one of these areas that can be affected is the visual system. Concussions cause neurons not to function properly in their normal capacity. When the injured neurons are in the visual system, it can cause the patient to experience numerous eye symptoms, one of the most common being blurry vision.
What are the Symptoms of Convergence Insufficiency? Most symptoms of convergency insufficiency are noticed when doing close work, such as computer work, reading, deskwork, and viewing screens close to the face (playing a handheld video game). The symptoms often experienced by those with convergence insufficiency include:
- Strain of eyes, especially with and after reading
- Blurry vision
- Headaches (often after reading)
- Double vision
- Words jumping on a page and frequent loss of place
- Short attention span and trouble concentrating
- Squinting or covering an eye to gain better sight during an activity
- Increased sleepiness during activity
- Problems with dizziness and/or motion sickness
- Trouble remembering words read
Detection and Diagnosis of Convergence Insufficiency: An eye chart eye exam to test visual acuity does not detect convergence insufficiency. In fact, a person can have 20/20 vision and still have convergence insufficiency. Because during a well-check visit and during school screenings only the basic eye exam is done, this diagnosis is often missed. To detect convergence insufficiency after a concussion, we use the Vestibular Ocular Motor Screen (VOMS). This test screens for both vestibular and visual abnormalities that are common after a concussion. The screen involves the patient moving their head and eyes in 6 different ways and rating their symptoms after each trial. These eye and head movements stress the vestibular system and the visual system and give us valuable information on how the systems are working. It is common for the tests to produce significant symptoms within a few days after the injury. If worsening symptoms or abnormal findings persist after the 1.5 to 2-week mark, referrals and appropriate treatments need to be started.
Treatment of Convergence Insufficiency: Most people fully recover from a concussion within about 3-4 weeks; if the vestibular or visual system is significantly involved, the duration can be longer. If your provider determines that there is an oculomotor component to your injury, like convergence insufficiency, they will likely refer you to a physical therapist. The physical therapists to whom we refer have undergone additional education and training in the vestibular and oculomotor system and are excellent at what they do. These therapists will give the patient many challenging exercises to retrain the injured pathways in the brain. They often encourage patients to push themselves until symptoms begin to worsen and then stop to let the symptoms decrease. This can help the concussion recovery process. This approach may not be recommended for every patient, so we advise talking with your provider about the best way to recover in your individual case.
Kapoor, N., Ciuffreda, K. (2002). Vision Disturbances Following Traumatic Brain Injury. Current Treatment Options in Neurology, 4:271–280.
Kontos, A., Deitrick, J.M., Collins, M.W., Mucha, A. (2017). Review of Vestibular and Oculomotor Screening and Concussion Rehabilitation. Journal of Athletic Training, 52(3):256–261.
Barnett, B.P., Singman, E.L., (2015). Vision Concerns After Mild Traumatic Brain Injury. Current Treatment Options in Neurology, 17:5.
Pearce, K.L., Sufrinko, A., Lau, B.C., Henry, L., Collins, M.W., Kontos, A.P., (2015) Near Point of Convergence After a Sport-Related Concussion: Measurement Reliability and Relationship to Neurocognitive Impairment and Symptoms. Am J Sports Me