Screens that feel too bright. Sunlight that makes you wince the moment you step outside. Fluorescent lights at the grocery store that leave you dizzy or exhausted before you’ve even made it down one aisle.

If this sounds familiar, you’re not imagining it, and you’re not alone. Light sensitivity, medically known as photophobia, is a common but often misunderstood symptom. It’s rarely a problem with your eyes themselves. More often, it’s a sign that something in your nervous system is struggling to process visual input the way it used to.

Here are four of the most common reasons light sensitivity happens.

1. Vestibular Dysfunction

Your vestibular system, centered in the inner ear, works closely with your brain to coordinate movement and visual signals. When you turn your head, your eyes and inner ear are supposed to sync up seamlessly so your brain gets a stable picture of the world.

When that system isn’t functioning properly, your brain can struggle to filter and process visual information correctly, and bright or busy visual environments (like scrolling on a phone or walking through a store) can become overwhelming.

2. Post-Concussion Changes

After a concussion, the brain’s visual processing pathways don’t always heal on the same timeline as the rest of the body. Even when other symptoms have faded, visual processing can remain disrupted for weeks or months.

This is why light sensitivity is one of the most common lingering post-concussion symptoms, and one of the most frequently dismissed, since it doesn’t show up on standard imaging.

3. Migraine-Related Sensitivity

For many people, light sensitivity is tied to migraine physiology. In a migraine-prone nervous system, neural pathways can become hypersensitive, amplifying normal light input into something that feels painful or overwhelming, even outside of an active migraine episode.

This is different from a typical eye-strain response. It’s a nervous system that has become primed to overreact to a stimulus that shouldn’t cause pain in the first place.

4. Autonomic Nervous System Dysregulation

Your autonomic nervous system (ANS) is responsible for filtering and regulating background stimuli so your brain isn’t constantly overwhelmed by every sound, light, or sensation around you. When the ANS is dysregulated, that filtering breaks down, and everyday stimuli like light can trigger an outsized response.

This is often connected to broader autonomic symptoms like fatigue, heart rate irregularities, or temperature dysregulation, which is why light sensitivity rarely shows up in isolation.

You Don’t Have to Just Live With It

Because light sensitivity has several distinct underlying causes, treating it effectively starts with figuring out which one (or which combination) is actually driving your symptoms. Sunglasses and dimmed screens might help you get through the day, but they don’t address why your nervous system is reacting this way in the first place.

At Nexus Neuro, we use functional testing, including vestibular and autonomic nervous system assessments, to identify exactly what’s driving your light sensitivity. From there, we build a treatment plan aimed at correcting the underlying dysfunction, not just helping you avoid bright rooms.

If screens, sunlight, or fluorescent lights have suddenly become too much, it’s worth finding out why. Schedule a consultation with Nexus Neuro: Brain + Body and start building a plan that addresses the cause, not just the discomfort.

📞 Call 317-884-8824 or visit nexusneurohealth.com to book your appointment today.