Blurry Vision, Eye Strain and Dizziness After Concussion: When 20/20 Vision Isn't the Whole Story

You have blurry vision, headaches when reading, light sensitivity, eye strain, or dizziness in busy environments. So you go to the eye doctor, read the letters on the eye chart, and are told: “Your vision is fine.” That can be incredibly confusing after a concussion, because your eyes clearly do not feel fine.

The missing piece is that seeing clearly is only one part of vision. You can have 20/20 visual acuity while struggling with how accurately your eyes move, how well they work together, how quickly they change focus, or how your brain integrates vision with information coming from your vestibular system and neck.

In an episode of Life After Impact, I spoke with optometrist Dr. Paul Brewer about why these problems can occur after concussion—and why they may be missed during a routine eye examination.

20/20 Doesn't Mean Your Entire Visual System Is Normal

An eye chart primarily measures visual acuity: your ability to clearly resolve a stationary target at a particular distance. But vision requires much more than clarity. Every day, your brain has to control your eyes as they move across a page, follow moving objects, shift between near and far targets, coordinate both eyes, stabilize your visual world as your head moves, and process an enormous amount of visual information.

Several of these functions can become disrupted after concussion.

Why You Shouldn't Automatically Start Doing Eye Exercises

Search online for concussion vision exercises and you will quickly find pencil push-ups, Brock strings, and other exercises. They can be useful—for the right problem. But Dr. Brewer makes an important point: someone struggling with divergence, peripheral processing, vestibular integration, or another visual deficit may need something entirely different.

In some cases, repeatedly training the wrong function could aggravate symptoms rather than improve them. The principle is simple: test first, treat second. Rather than asking, “What's a good eye exercise for concussion?” the more useful question is, “Which part of my visual system isn't functioning efficiently?”

Why Grocery Stores Can Make You Dizzy

Many people with concussion say they cannot tolerate grocery stores, crowds, airports, scrolling screens, or busy restaurants. These environments place enormous demands on the visual system. Imagine walking through a grocery store: people move around you, carts cross your path, your eyes scan shelves while your head turns, objects fill your peripheral vision, and bright lights illuminate the store.

Your brain has to decide what visual information matters—and what it can safely ignore. After concussion, that filtering may become less efficient. Dr. Brewer describes this partly as a problem of filtering information and correcting sensory errors. When too much information arrives at once, the brain may become overwhelmed.

This helps explain why someone can walk into a store feeling relatively okay and leave feeling completely depleted.

Vision, Balance and Your Neck Have to Agree

Your visual system does not operate independently. To understand where you are in space, your brain continuously compares information from three major systems: vision (what am I seeing?), the vestibular system (how is my head moving relative to gravity?), and proprioception (where are my head, neck, and body positioned?).

Ideally, these information sources agree. But after concussion—especially when there has also been a neck injury—they may not. Dr. Brewer compares the problem to trying to navigate using multiple maps that do not quite line up. If the visual system tells your brain one thing while vestibular or cervical systems provide conflicting information, your brain has to continually reconcile the mismatch.

That mismatch may contribute to dizziness, visual motion sensitivity, headaches, neck tension, and fatigue. It also helps explain why some people need rehabilitation that addresses visual, vestibular, and cervical function together rather than treating each system in isolation.

Light Sensitivity Isn't Always the Same Problem

Light sensitivity is another common post-concussion complaint, but photophobia is a symptom, not an explanation. Different factors may contribute, including dry or irritated eyes, abnormal pupillary responses, binocular vision problems, gaze instability, sensitivity to flickering light, and altered visual processing.

Someone bothered primarily by fluorescent lighting may therefore have a different problem from someone whose eyes burn and water whenever they are exposed to bright light. Understanding the mechanism matters because the treatment approach may be different.

Could Visual Problems Be Contributing to Your Fatigue?

This may be one of the most overlooked pieces of post-concussion fatigue. Imagine that every time your eyes move, your brain has to make additional corrections; every time you walk, visual and vestibular systems have to work harder to keep the world stable; and every time you enter a busy environment, your brain struggles to filter unnecessary visual information.

You may still be able to function, but functioning becomes inefficient. That can help explain a common experience in recovery: “I can do it—but doing it completely wipes me out.” Poorly integrated visual and vestibular systems can create a constant push-and-pull for the brain to manage throughout the day.

What If Your Eye Exam Was Normal but You're Still Having Symptoms?

A normal eye-health examination is valuable. We want to know that the eyes themselves are healthy and that there is not an ocular disease or injury requiring treatment. But if you have been told your eyes are healthy and you are still experiencing blurry or double vision, headaches with reading, eye strain, difficulty shifting focus, dizziness with visual activity, visual motion sensitivity, screen intolerance, light sensitivity, or difficulty in grocery stores or crowds, it may be worth asking whether you have had a more comprehensive assessment.

Depending on your symptoms, that can include assessment of eye movements, binocular vision, accommodation, and visual-vestibular function by a clinician with specific expertise in post-concussion visual rehabilitation.

A “Normal” Eye Exam Doesn't Mean Your Symptoms Aren't Real

The visual system is extraordinarily complex. Reading the bottom line of an eye chart tells us something important, but it does not tell us how accurately your eyes move, how efficiently they work together, how quickly they refocus, how your brain processes visual motion, or how well vision coordinates with your vestibular system and neck.

If reading, screens, driving, grocery stores, or simply moving through the world still does not feel right, consider asking a different question: not just, “How well can my eyes see?” but, “How well is my brain controlling and processing what my eyes see?” That may be the question that begins to provide answers.

This article is educational and is not a substitute for individualized medical advice. If visual symptoms are persistent, worsening, or affecting safety, seek evaluation from an appropriately qualified healthcare professional.