The Lights Were Always Brighter: New Science Confirms Autistic Sensory Overload
How a 2024 study finally measures what autistic people have described for years.
Autistic people have long said the lights hit harder. A 2024 study shows it's true — the sensory overload starts at the retina. In plain language, here's what the science says — and why it matters for real-world access.
Introduction: The Experience We’ve Always Described
Huang, Q., Ellis, C. L., Leo, S. M., Velthuis, H., Pereira, A. C., Dimitrov, M., Ponteduro, F. M., Wong, N. M. L., Daly, E., Murphy, D. G. M., Mahroo, O. A., & McAlonan, G. M. (2024). Retinal GABAergic alterations in adults with autism spectrum disorder. Journal of Neuroscience, 44(14), e1218232024. https://doi.org/10.1523/JNEUROSCI.1218-23.2024
The study is titled Retinal GABAergic Alterations in Adults with Autism Spectrum Disorder — Huang et al., 2024. Above, you can see the official “Significance Statement” they’ve provided. It’s dense. It’s technical. Frankly, unless you already live inside the language of neuroscience, it’s almost impenetrable. Like much of the clinical research on autism, it’s written for an audience who already knows the frameworks, the chemical pathways, the specialised terms.
But buried inside all that heavy language is something quietly astonishing — not to those of us living it, but to the systems that have so long demanded evidence before belief. What this study shows is something autistic people have been trying to explain for decades.
You know that moment when you walk into a supermarket, or a pharmacy, or an office conference room, and the lights hit like needles? When your eyes water slightly, your stomach clenches, your shoulders tense, and you can feel your whole system bracing? That experience — that sense of the world arriving too hard, too fast, too bright — isn’t imaginary. It isn’t anxiety. It isn’t fussiness. It’s the physiological reality of how our nervous systems are built. And now, they can measure it.
Quite literally: for many autistic people, the lights really are brighter. Brighter in a way that overwhelms. Brighter in a way that aches — behind the eyes, across the scalp, down into the gut. Brighter in a way that drains the limited reserves we walk into the room carrying — the spoons we needed for thinking, speaking, holding ourselves together. The lights are not just visually intense. They are metabolically expensive.
The Study in Simple Terms
Let’s step into the study itself. I’m going to stay in plain language here, because otherwise we’d be knee-deep in dense neuroscience terminology again — and the whole point is to make this accessible.
What the researchers did was actually quite simple in its design, even if the language they use makes it sound more complicated. They wanted to test how autistic and non-autistic people’s eyes respond to light — not just subjectively (“does this feel too bright?”), but by measuring the raw electrical activity inside the eye as it first receives light. This is called an electroretinogram, or ERG — you can think of it as similar to an EKG that records your heartbeat, but instead of the heart, it records how your retina (the light-sensitive layer at the back of your eye) reacts when light arrives.
Now, they didn’t just shine any random light. They used a very controlled mixture of red, green, and blue light, at very specific wavelengths. You can see that in the chart I’ve included above. The black line shows what they used in the study — three precise peaks: one at 470 nanometres (blue), one at 530 (green), and one at 621 (red). This very controlled mixture is not the kind of light most of us encounter in real life. It’s clean. Balanced. Neutral. Almost surgical. And even with that carefully balanced “white” light, autistic participants’ retinas responded more strongly.
The first thing your retina does when light hits is produce what’s called the a-wave — that’s the first electrical response, when your photoreceptor cells fire. For autistic people in the study, this a-wave was significantly larger than for the non-autistic group. That means the incoming light signal hit harder, right from the very first stage of processing — before the brain even gets involved. The system is already amplifying at the front gate.
They then introduced a drug called arbaclofen — a medicine that works on something called the GABA-B system, which helps the body regulate and dampen incoming sensory signals. You can think of GABA as one of the nervous system’s natural circuit breakers. If everything is working smoothly, it helps prevent sensory overload by quieting down signals that are coming in too strong.
It’s interesting to note here that the particular form of arbaclofen they used isn’t something you’ll find at the local chemist. It’s a version that was once developed for other conditions but later discontinued. Right now, it’s being explored off-label, mostly in research settings, including some studies on autism. This isn’t a treatment on offer — at least not in any practical, day-to-day sense. In this study, the drug was used as a tool to test how the autistic sensory system responds when the usual dampening mechanisms, the GABA-B system, are chemically boosted.
Again, GABA helps tone down signals that might otherwise flood the system. When autistic participants took arbaclofen, their retinal response decreased — it came closer to the non-autistic level. In other words: with some chemical help, the circuit breaker engaged, and the overwhelming response calmed a little. For the non-autistic group, interestingly, the drug nudged things slightly in the opposite direction — increasing their response — but the shift wasn’t as strong.
This is a key finding. It suggests that some of the sensory overload autistic people experience may come, at least partly, from differences in how our inhibitory systems — those circuit breakers — are working right from the very first moment light enters the system. And remember: this was measured using neutral, highly controlled light. Real-world lighting — fluorescent bulbs, LED office lights, phone screens — usually hits us with far more intense blue light, as you can also see in the chart. The dashed lines show those real-world light sources. They spike much harder, especially in the blue range, and that’s where many of us feel the worst effects.
So: yes. The lights are brighter. But it’s not just brightness. It’s that the control systems that should help buffer the sensory signal aren’t buffering in quite the same way for autistic people. The signal gets through more forcefully, travels deeper, and starts draining energy from the system — fast.
Why This Matters (More Than Just the Retina)
So why does any of this matter? After all, this is just about the retina, right? Just about how the eyes handle light?
Not quite. And this is where it gets much more interesting — because the retina is only the very first step. What happens at the retina feeds directly into everything that comes after: the brain’s processing of visual input, yes, but also how the entire sensory system regulates itself. The researchers didn’t stop with measuring the eye — they compared these retinal results with earlier data they’d collected on how the same participants’ brains responded to sounds. And what they found was that the people who had bigger responses in their retinas also tended to show stronger brain responses to sound.
In other words: this isn’t limited to vision. The same differences seem to show up across multiple senses. The same GABA system that helps manage the flow of information coming from the eyes also plays a role in how the brain regulates other kinds of input — like sounds, touches, smells, or movement. And importantly, the strength of these sensory responses also linked to autistic traits more broadly. The more intense the retinal response, the higher the individual tended to score on measures of autistic experience.
This isn’t just about “light sensitivity.” It’s pointing toward something bigger: a difference in how our whole sensory system filters — or doesn’t filter — the world as it comes in. The overload many autistic people describe isn’t a series of isolated quirks, but part of a deeper pattern in how the body regulates sensory flow. The circuit breakers aren’t tripping in the usual places. The signals keep coming.
What This Means for Everyday Life
So what does all this mean in real life? This is where it starts to feel very familiar for many of us.
Think about fluorescent lights — the kind you find in supermarkets, office buildings, schools, hospitals. The ones that seem to hum faintly, flicker just enough to make your head ache, and send sharp, cold light bouncing off every shiny surface. Or think about the harsh glare of LED headlights at night (ugh!). Or the blue-white brightness of phone screens and computer monitors that seem to leave your eyes burning after only a short while. For many autistic people, these aren’t just mild annoyances. They’re triggers for overwhelm. The lights don’t just light up the room — they feel like they’re punching directly into the body.
And this is the part that non-autistic people often misunderstand. When we ask to turn off the overheads, or dim the lights, or wear tinted lenses indoors, it’s not a personal preference or a matter of comfort. It’s a physiological accommodation. Our sensory systems are processing that light differently — starting right at the retina. What might feel neutral or even pleasant to someone else can, for us, very quickly drain energy, cause pain, and push us closer to shutdown.
It’s worth looking back at the chart again here. The controlled light used in the study — that neat, balanced black line — still produced a stronger response in autistic retinas. But most real-world lighting (the dashed and dotted lines) isn’t balanced like that at all. It’s full of hard spikes, especially in the blue range. Device screens are some of the worst offenders, throwing out narrow, intense peaks of blue light that hit directly into this sensitive system.
This is why screen fatigue is so common for autistic people. It’s not just eye strain. It’s not about sitting too close or forgetting to blink. It’s that the incoming light itself is exhausting our ability to regulate — every second we’re exposed. The system keeps taking in the signal, but struggles to buffer it. This is one of the reasons many autistic people — myself included — wear glasses with blue-light filtering lenses. The aim isn’t to block all light, but to take the edge off that sharp, high-energy blue spike that hits hardest. It’s a way of easing some of the constant metabolic load that comes with simply looking at a screen. The glasses aren’t a luxury or a fad. For many of us, they’re part of what allows us to function.
A Word on "Validation" (The Politics of Measurement)
It’s worth pausing here to talk about what’s happening underneath all this. Because whilst the study is important — and it is — it’s also important to name what it’s really doing.
Autistic people have been describing this experience for decades. We’ve said that the lights feel too bright, that the sounds feel too loud, that the world comes in too hard and too fast. We’ve tried to explain the exhaustion that follows even everyday sensory exposure. None of this is new to those of us living it. What’s new is that now, with the right equipment, science can finally measure it in a way that institutions are willing to recognise.
But let’s be clear: measurement isn’t what makes it real. The experience was always real. The pain, the overwhelm, the depletion — these didn’t arrive because someone finally pointed an electrode at a retina and wrote up the findings in technical language. What studies like this do is catch the science up to lived experience. They offer data that can be handed to policy-makers, educators, occupational health teams — people who may have dismissed our words but might take notice when a chart appears.
This is the politics of measurement. It’s not just about evidence. It’s about power. Whose accounts get treated as valid? Whose bodies are believed without machines to confirm their testimony? Studies like this don’t give us legitimacy — but they can give us another tool in the ongoing work of advocacy. Sometimes you need the data, not because you doubted yourself, but because systems still doubt you.
Practical Takeaways for Autistic and Non-Autistic Readers
So what can we actually do with all this? For autistic people, many of us already know what we need. The challenge is often getting others to understand why those needs are real, and why they matter.
For parents, teachers, employers, clinicians — this is your part. Sensory-friendly lighting isn’t a luxury. It’s not a favour. It’s basic access. When an autistic person asks for the fluorescents to be switched off, or requests a desk lamp instead of overhead lights, or wears tinted lenses indoors, what they’re doing is managing sensory load that starts from the very first point where light enters the body. These aren’t quirks or preferences. They’re physiological strategies to reduce harm.
One of the practical values of a study like this is that it gives us language we can hand to the people around us — especially those who might still think, quietly or not-so-quietly, that we’re being dramatic, or difficult, or sensitive in the wrong kind of way.
Here’s something simple that you might use, if you need a letter or explanation to hand to a teacher, a supervisor, an HR department, or a healthcare provider:
Dear [Name],
As an autistic person, I experience sensory processing differences that can make certain kinds of lighting physically painful and exhausting. This isn’t simply a matter of comfort or preference — it’s part of how my nervous system processes incoming sensory information. A 2024 study (Huang et al., Journal of Neuroscience, 44(14), e1218232024) has shown that autistic people’s eyes respond more strongly to light at the very first stage of processing, even before the brain interprets what’s being seen. This helps explain why bright, flickering, or blue-heavy lighting (such as fluorescent tubes or device screens) can lead to overwhelm, pain, and fatigue.
When I request adjustments to lighting — for example, dimmer settings, warm-toned bulbs, filters, or the use of my own tinted lenses — I am managing real sensory overload. These adjustments allow me to function with less pain and preserve my energy across the day.
Thank you for your understanding and support in making this space more accessible.
If you’re reading this as a non-autistic person: this is what solidarity can look like. It doesn’t require specialist training. It just requires believing people when they tell you what their bodies are doing. The science is catching up. You don’t have to wait for more studies to offer accommodations.
Conclusion: The Lights Were Always Brighter
And so we circle back to where we began.
For many of us, this was never in doubt. We’ve felt the lights hit too hard. We’ve carried the headaches, the fatigue, the quiet dread of entering rooms that feel like standing under a searchlight. We’ve learned to manage it, to mask it, to make adjustments where we could, often without much understanding from others. Long before anyone put electrodes near our eyes or published a study, we were living this reality.
Now, at last, the measuring devices have caught up. The data exists. The charts have been drawn. But the truth was already here — in our bodies, in our words, in the quiet endurance so many of us have practised. What this study offers isn’t discovery. It’s confirmation.
So to the non-autistic people reading: listen sooner next time. Don’t wait for the machines. We knew. Now you can measure it. The lights were always brighter.