A concussion is a type of traumatic brain injury that occurs when the brain experiences a bump, blow, or jolt, or from a hit to the body that causes the head and brain to move rapidly back and forth. This sudden movement can cause the brain to bounce or twist inside the skull, leading to chemical changes and sometimes stretching or damaging brain cells. These alterations can temporarily disrupt normal brain function, often affecting the brain’s ability to process visual information.
Common Visual Symptoms After a Concussion
Following a concussion, individuals often experience a range of visual problems:
- Blurred vision, where objects appear fuzzy or out of focus, often with difficulty shifting focus between near and far objects.
- Double vision (diplopia), when the eyes struggle to work together to form a single image.
- Photophobia, an increased sensitivity to light that can make bright environments or screens uncomfortable.
- Eye strain, especially during visually demanding tasks like reading or using electronic devices, which can also trigger or worsen headaches.
- Difficulty tracking moving objects, such as a ball in sports, or smoothly following lines of text while reading, leading to losing one’s place or feeling fatigued more easily.
- Problems with depth perception, judging distances, or the location of objects in relation to each other, impacting daily activities like walking on stairs or parking a car.
How Concussions Impact the Visual System
Concussions primarily affect vision not by damaging the eyes themselves, but by disrupting the intricate neural pathways that connect the eyes to the brain. The rapid brain movement during an injury can stretch and damage neurons, altering the chemical and metabolic makeup of brain cells and impacting their ability to communicate effectively. This can lead to a condition sometimes referred to as post-trauma vision syndrome (PTVS), which encompasses various visual disturbances. The brain’s visual processing centers can be temporarily or permanently disrupted, hindering the coordination between central and peripheral vision. This impairment affects areas responsible for visual processing, eye movement control, and visual-vestibular integration, which helps maintain focus during head movement.
Diagnosis and Management of Post-Concussion Vision Issues
Diagnosis
Healthcare professionals diagnose post-concussion vision issues through a comprehensive evaluation that includes a detailed medical history and a neurological exam. This assessment checks vision, hearing, balance, coordination, and reflexes. Cognitive testing may also be conducted to evaluate thinking skills, memory, and concentration. For some individuals, especially those with severe headaches, seizures, or worsening symptoms, brain imaging tests like CT scans or MRIs may be used to check for bleeding or swelling.
Management
Management strategies often involve a combination of approaches, beginning with initial symptom management and task modification. This includes reducing time spent on visually demanding activities like screen time and reading, and incorporating breaks.
Vision therapy exercises, often guided by neuro-optometrists or physical therapists, are frequently employed to improve eye coordination, focusing, and tracking abilities. Specific exercises might include smooth pursuit exercises for tracking moving objects, convergence exercises to help eyes work together for near tasks, and saccadic eye movements for rapid refixation.
Light modification is another common strategy, such as wearing polarized sunglasses outdoors or using anti-glare filters on screens. Adjusting screen brightness and font size can also reduce visual strain. A gradual return to activities, with appropriate academic or work accommodations like larger fonts or preprinted notes, is also recommended to avoid overwhelming the visual system during recovery.
When to Seek Immediate Medical Attention
Certain symptoms after a head injury warrant immediate medical evaluation:
- Sudden vision loss in one or both eyes, or if double vision is persistent or worsening.
- Any noticeable change in pupil size, where the black parts of the eyes are bigger than usual or unequal.
- A severe headache that worsens over time, especially if accompanied by vision changes.
- Repeated vomiting, seizures, difficulty staying awake, or any new weakness or numbness in the arms or legs.
- If clear fluid or blood drains from the ears or nose, or if there is bruising around the eyes without direct eye injury.