Pritam Dutta, M.Optom
Lecturer, Ridley College of Optometry, Optometrist, Chandraprabha Eye Hospital Jorhat, Assam
Traumatic Brain Injury (TBI) is defined, “as an alteration in brain function, or other evidence of brain pathology, caused by an external force”1. The mode of TBI can be either due to falls, assaults, road traffic accidents, pedestrian accidents, sports-related, industrial and workplace-related accidents2. Among all, mild TBI accounts for 75% alone3. The American Congress of Rehabilitation Medicine (ACRM) defined mild TBI as “traumatically induced physiological disruption of brain function, as manifested by at least one of the following: any period of loss of consciousness, any loss of memory for events immediately before or after the accident, an alteration in the mental state at the time of the accident (disoriented or confused), focal neurological deficit that may or may not be transient”.
There occurs a cellular and sub cellular level damage in mild TBI without the involvement of any haemorrhage or any changes detectable in imaging techniques4. Visual symptoms following TBI include near vision problems with prolonged reading, glare, photosensitivity, and difficulty maintaining fusion5. The most common symptoms an individual develops following mild TBI are headache, dizziness, fatigue, irritability, insomnia, difficulty concentrating, memory problems, and/or intolerance of stress6. Several studies have found convergence insufficiency, accommodative dysfunction, and oculomotor problems to be the commonest among patients following mild TBI7 (see Table 1). It is reported that there occurs a diffuse and multiple axonal damages which in turn causes disruption of accommodation and vergence neural nerve fibers leading to certain dysfunctions8. The saccade and pursuit share a common premotor neural pathway which contains neurons of inhibitory omnipause and neurons of pursuits and saccades in the paramedian pontine reticular formation (PPRF) and any lesions following TBI to this area leads to oculomotor dysfunction9. These alterations in the accommodation, vergence and versions also have an impact on the academic performances of adult/children, leading to lack of concentration, difficulty performing near tasks, and asthenopia which results in achieving lower grade points when compared to a non-TBI child10,11.
|Common ocular conditions||Findings in mild TBI|
|Accommodation||Reduced amplitude, time constant, peak accommodative velocity12|
|Vergence||Reduced convergence amplitude and poor fusional vergence13|
|Oculomotor based reading dysfunction||Reduced reading speed, poor comprehension, deficit in saccades and pursuits14,15|
|Photosensitivity||Found in a larger prevalence of mild TBI individuals due to poor pupillary dynamics16|
|Pupillary response||Delayed pupillary latencies and velocities17|
|Vestibular dysfunction||Associated with symptoms such as blurred vision, dizziness, nausea etc. due to various neurometabolic changes occurring following a mild TBI19|
Scattered, restricted; might be homonymous 22
Table 1: Common ocular findings in mild TBI.
A thorough ocular examination including the tests for binocular vision, eye movements, visual processing and visual efficiency would provide an estimation of the underlying abnormalities in mild TBI individuals. Therefore, eye care professionals play a crucial role in diagnosing and treating these visual consequences, working as an integrated team in a hospital or an individual set up. The Neuro-optometric based vision therapy and other treatment modalities (see Table 2) along with a proper referral for managing the associated non-ocular based problem would significantly make a difference in improving the quality of life in those patients.
|Accommodation||Accommodative training (vision therapy)15|
|Vergence||Vergence training (vision therapy)15|
|Reading deficits||Oculomotor rehabilitation15|
|Vestibular dysfunction||Vestibular therapy20,21|
|Visual field||Prisms and visual scanning20,21|
Table 2: Management options for associated conditions following mild TBI.
- Thomas R.Frieden FSC. Report to Congress on Traumatic Brain Injury in the United States : Understanding the Public Health Problem among Current and Former Military Personnel.; 2013.
- Reznik, J. E., Biros, E., Marshall, R., et.al. (2014). Prevalence and risk-factors of neurogenic heterotopic ossification in traumatic spinal cord and traumatic brain injured patients admitted to specialised units in Australia. Journal of musculoskeletal & neuronal interactions, 14(1), 19–28.
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- Barnett, B. P., & Singman, E. L. (2015). Vision concerns after mild traumatic brain injury. Current treatment options in neurology, 17(2), 329. https://doi.org/10.1007/s11940-014-0329-y
- Padula W V, Simmons-grab D, Cannelongo J, et al. Visual Dysfunction Following a Neurological Event. NORA. 1995
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- Matuseviciene, G., Johansson, J., Möller, M., et al. (2018).Longitudinal changes in oculomotor function in young adults with mild traumatic brain injury in Sweden: an exploratory prospective observational study. BMJ open, 8(2), e018734. https://doi.org/10.1136/bmjopen-2017-018734
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- Ciuffreda, K. J., Kapoor, N., Rutner, D., et.al. (2007). Occurrence of oculomotor dysfunctions in acquired brain injury: a retrospective analysis. Optometry (St. Louis, Mo.), 78(4), 155–161. https://doi.org/10.1016/j.optm.2006.11.011
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- Swanson, M. W., Weise, K. K., Dreer, L. E., et.al. (2017). Academic Difficulty and Vision Symptoms in Children with Concussion. Optometry and vision science : official publication of the American Academy of Optometry, 94(1), 60–67. https://doi.org/10.1097/OPX.0000000000000977
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- Capó-Aponte, J. E., Urosevich, T. G., Temme, L. A., et. al. (2012). Visual dysfunctions and symptoms during the subacute stage of blast-induced mild traumatic brain injury. Military medicine, 177(7), 804–813. https://doi.org/10.7205/milmed-d-12-00061
- Thiagarajan, P., Ciuffreda, K. J., Capo-Aponte, J. E., et.al. (2014). Oculomotor neurorehabilitation for reading in mild traumatic brain injury (mTBI): an integrative approach. NeuroRehabilitation, 34(1), 129–146. https://doi.org/10.3233/NRE-131025
- Truong, J. Q., & Ciuffreda, K. J. (2016). Objective Pupillary Correlates of Photosensitivity in the Normal and Mild Traumatic Brain Injury Populations. Military medicine, 181(10), 1382–1390. https://doi.org/10.7205/MILMED-D-15-00587
- Ciuffreda, K. J., Joshi, N. R., & Truong, J. Q. (2017). Understanding the effects of mild traumatic brain injury on the pupillary light reflex. Concussion (London, England), 2(3), CNC36. https://doi.org/10.2217/cnc-2016-0029
- Arciniega, H., Kilgore-Gomez, A., Harris, A., et.al. (2019). Visual working memory deficits in undergraduates with a history of mild traumatic brain injury. Attention, perception & psychophysics, 81(8), 2597–2603. https://doi.org/10.3758/s13414-019-01774-9
- Gurley, J. M., Hujsak, B. D., & Kelly, J. L. (2013). Vestibular rehabilitation following mild traumatic brain injury. NeuroRehabilitation, 32(3), 519–528. https://doi.org/10.3233/NRE-130874
- Ciuffreda, Kenneth & Diana, O & Ludlam, Diana. (2011). Conceptual Model of Optometric Vision Care in Mild Traumatic Brain Injury. The Journal of Behavioral Optometry. 22.
- Ciuffreda, K.J., Ludlam, D.P., & Kapoor, N. (2009). Clinical Oculomotor Training in Traumatic Brain Injury.
- Suchoff, I. B., Kapoor, N., Ciuffreda, K. J., et.al. (2008). The frequency of occurrence, types, and characteristics of visual field defects in acquired brain injury: a retrospective analysis. Optometry (St. Louis, Mo.), 79(5), 259–265. https://doi.org/10.1016/j.optm.2007.10.012