A concussion is a mild form of traumatic brain injury (TBI) resulting from a blow to the head or a rapid, jarring motion of the body. This sudden trauma causes a temporary disruption of normal brain function, which can manifest in a wide range of physical and cognitive symptoms. Blurry vision is one of the most common symptoms reported following this type of injury. This visual disturbance signals a communication issue within the brain’s processing centers. Understanding this connection is important for seeking appropriate care and beginning recovery.
Blurry Vision and Related Visual Symptoms
While blurred vision is a frequent complaint, it rarely occurs in isolation after a concussion, often being part of a cluster of related visual problems. Blurred vision may result from a temporary inability to focus clearly on objects at any distance, making reading or viewing screens difficult.
Another common manifestation is diplopia, or double vision, which occurs when the eyes fail to work together as a coordinated team. Light sensitivity, known as photophobia, causes discomfort or pain when exposed to bright lights or electronic screens. People frequently report eye strain, or asthenopia, especially during tasks that require sustained visual effort. These symptoms collectively indicate a disruption in the system responsible for coordinating eye movements and visual perception.
Visual tracking issues are also prevalent, making it difficult to smoothly follow a moving object or to maintain one’s place while reading a line of text. Objects in motion may appear jumpy or unstable. These varied symptoms confirm that a concussion impacts the entire visual system, not just the clarity of sight.
The Neurological Cause of Vision Disruption
The visual symptoms following a concussion do not result from physical damage to the eyes, but rather from a breakdown in the neural communication pathways between the eyes and the brain. More than half of the brain’s pathways are dedicated to processing visual information and controlling eye movements, making this system vulnerable to injury. The mechanical force of a concussion causes microscopic damage or temporary functional impairment in the areas controlling eye teaming and focusing.
One key mechanism is Convergence Insufficiency, where the eyes struggle to turn inward to maintain focus on objects up close. This reduced ability forces the brain to strain to align the two images, resulting in blurred vision, double vision, and headaches. Accommodative Insufficiency affects the eye’s ability to rapidly change focus between near and far targets. This dysfunction is a common source of blurriness during near-work tasks.
Furthermore, the Vestibulo-Ocular Reflex (VOR) can be disrupted, affecting the brain’s ability to stabilize vision during head movements. The VOR normally ensures that your gaze remains steady even as your head moves, but impairment can cause the world to appear blurred or shaky with any motion. This breakdown in the visual-vestibular system contributes to blurriness, dizziness, and unsteadiness following a concussion.
When to Seek Immediate Medical Attention
While many concussion symptoms improve with rest, certain red-flag symptoms require immediate emergency medical evaluation. Seek urgent care if you experience a rapid and severe worsening of vision, or any sudden, complete loss of vision in one or both eyes. Persistent or severe double vision that does not resolve quickly also warrants prompt medical attention to rule out serious complications.
Other neurological indicators that necessitate an emergency room visit include:
- Difficulty staying awake
- Having a seizure
- Experiencing weakness or numbness on one side of the body
- Problems with walking or balance
- Continuous or worsening headaches
- Repeated vomiting, or any clear fluid draining from the nose or ears
For non-emergency but persistent visual symptoms, follow-up evaluation should be conducted by a healthcare professional specializing in post-concussion care, such as a neuro-optometrist or a neurologist.
Management and Recovery of Post-Concussion Vision Issues
Recovery from post-concussion visual issues begins with prescribed cognitive and physical rest, allowing the brain the necessary time to heal and normalize its function. During the initial period, minimizing visually demanding activities, such as reading, screen time, and complex tasks, helps reduce eye strain and prevent symptom flare-ups. Environmental adjustments are also beneficial, including reducing overall light exposure, wearing polarized sunglasses outdoors, and adjusting the brightness of electronic devices.
When symptoms persist beyond the initial recovery window, specialized treatment often involves neuro-optometric rehabilitation, commonly known as vision therapy. This is a customized program of exercises designed to re-establish the communication between the eyes and the brain. These activities specifically target improvements in eye teaming, focusing, and visual tracking skills that were impaired by the concussion.
Vision therapy exercises may include work to improve convergence and accommodation, potentially using therapeutic lenses or prisms to help align the visual input. The goal is to retrain the visual system to function efficiently and automatically, which can reduce blurriness, double vision, and eye fatigue. Consistent adherence to this rehabilitative training is often necessary to achieve a full recovery and restore comfort during daily visual tasks.