Why Your Vision Feels Glitchy After a Concussion—And How to Get It Back on Track
If you’ve ever had a concussion, you might have noticed that your eyes don’t quite work the way they used to. Maybe text blurs when you read, lights feel unbearably bright, or objects in motion seem oddly disjointed. These aren’t just random annoyances—they’re symptoms of a deeper issue.
The problem isn’t necessarily with your eyes themselves. Instead, it’s your brain struggling to process visual information correctly. Think of it like a computer that’s technically fine—no broken hardware, no fried circuits—but is running a buggy operating system update that keeps causing weird usability issues.
The hierachial organization of the visual system, from the low level through to higher order processing.
The Visual System: The Brain’s Built-In Operating System
In 1991, neuroscientists Daniel J. Felleman and David C. Van Essen published a paper mapping out the hierarchy of the primate visual system. They found that vision isn’t handled in just one place; it’s a layered system, where each level processes increasingly complex visual tasks.
This system has five main levels:
• V1/Retina/LGN: Basic image processing—edges, contrast, and light-dark differences.
• V2 & V3: Intermediate-level processing—patterns, textures, and movement.
• V4: Color processing and object recognition.
• V5: Motion perception—tracking objects as they move.
At the very top of this hierarchy, the brain takes all this processed data and turns it into something meaningful—like recognizing a face, reading text, or calculating how far away a moving car is.
The hierarchial organization of successive Windows versions, with each version integrating with and building upon the previous version, from low-level Windows 1 through to higher order Windows 11.
How This is Like Windows Updates (Stick With Me Here…)
If the visual system were a computer, it would work a lot like Windows: each version builds on the previous one, adding complexity and better usability while still relying on older, lower-level functions.
• DOS / Legacy Windows (Retina & LGN): Handles raw data input (DOS), just like detecting light (retina).
• Windows 3.1/95/98 (V1 & V2): These early Windows versions brought in basic graphical interfaces.
• Windows XP/7/8/10 (V3, V4, V5): More advanced graphics, multitasking and networking.
• Windows 11 (Higher-Level Integration): Fully integrating all previous functions into a seamless user experience.
Sometimes you stumble upon relics of a bygone era in Windows. Take the command prompt: fire it up, and you’re whisked back to the days of DOS, as if Windows is saying, “Hey, wonder where I came from? Here’s a sneak peek at my skeleton!”
Similarly, the brain has its own throwback moments. Many optical illusions work by isolating and showcasing those older, less sophisticated systems hidden beneath your shiny conscious surface. It’s like a friendly nudge from your inner, vintage processor saying, “I may be ancient, but I am still working”.
The older foundation of todays Windows 11 can still be seen in various parts of the OS. The command prompt app shows some of the very earliest beginnings of Windows in the form of DOS
Optical illusions sometimes work by showing what the older parts in our visual system are doing. Here we have Mach bands, which are the darkish edges that show up at each shade change in the gradient (they aren’t actually there, its a construct of the older parts of your vision system, namely the retina and the LGN).
Post-Concussion Vision Problems = A Glitchy Update
Now, let’s say your brain is running “Windows 11” for vision. But then, a concussion hits. Suddenly, it’s as if your brain installed a corrupt update.
The hardware (your eyes) is fine, but higher-level processing starts running into infinite loops, lag, and crashes. This can show up as:
• Blurry vision → Higher processing centers failing to refine raw visual data.
• Light sensitivity → The system mismanaging brightness settings.
• Motion sensitivity → The motion-tracking software struggling to sync properly.
And at an especially frequent rate:
Depth perception issues → A desync between two background programs:
where_are_eyes_pointing.exe
where_are_eyes_focused.exe
Normally, these two programs should generate the same value: wherever you look, that’s where you focus. But after a concussion, they might start spitting out different numbers, triggering a visual system crash.
How This Creates an Infinite Loop (And Why It Feels Awful)
Let’s break this down with an example:
1️⃣ Your brain miscalculates where your eyes should converge on an object.
2️⃣ Your eyes try to correct by converging more.
3️⃣ The brain interprets this as a cue that the object must be closer than it actually is.
4️⃣ It then refocuses even more.
5️⃣ This throws off depth perception, triggering headaches, dizziness, and double vision.
6️⃣ Loop back to step 1. Repeat endlessly.
Sound familiar? This is why concussed patients often struggle with reading, screens, and moving objects—their visual system is trapped in a feedback loop, using up enormous brain resources just to function.
How Contoured Prism Lenses Hit “Ctrl-Alt-Del” on This Mess
The viewer has a mismatch between where the eyes are pointed (red dashes) and where the eyes are focused (green line). This makes the brain see double, which it instinctively tries to correct by converging the eyes more, which can initiate an endless loop of converging and re-focusing.
Now, here’s where things get cool. Specialized lenses—like contoured prism glasses (Neurolens®) —can force these two background programs to output the same value again.
By adjusting both focus and convergence simultaneously, these glasses:
✅ Instantly reset the system, ending the infinite loop.
✅ Free up brain bandwidth for more important tasks.
✅ Reduce symptoms sometimes within seconds of putting them on.
It’s the visual equivalent of pressing Ctrl-Alt-Del on a frozen computer: suddenly, everything starts working again.
Other Tools for Rebooting the Visual System
Contoured prism lenses aren’t the only trick in the book. Other tools work by reducing unnecessary processing load:
• Tinted Lenses: Adjust brightness processing to prevent overloading.
• Reading Glasses: Reduce strain by simplifying focus demands.
• Targeted Vision Therapy: Manually reprograms the system through structured exercises.
Regardless of the approach, the goal is the same: stabilize the system, free up mental processing power, and give the brain time to heal.
Final Thought: Let Your Brain Download the Patch
When your computer starts acting up after a bad update, you don’t immediately throw it away—you troubleshoot, reset background processes, and give it time to install the necessary fixes.
Your brain works the same way.
By resetting faulty visual processing loops, tools like contoured prism glasses, tinted lenses, and vision therapy allow your brain to regain normal function. And once the system is stable, it can finally do what it was designed to do: ‘download the necessary software patches’ and heal itself.
So if your vision is still glitchy after a concussion, don’t panic—you’re not broken, you’re just dealing with a bad update. With the right tools, you can reboot your system and get back to running smoothly again.
Dr. Burke is an optometrist practicing at Calgary Vision Centre. A large portion of his practice is devoted to helping post-concussion patients with their vision issues, and wears contoured prism glasses himself due to a personal history of concussions. Opinions above do not constitute medical advice, and readers should consult with their optometrist and health care team if they have questions or concerns about their eye health.
