Understanding Light Sensitivity

By Cheryl Wylie, MSc (PT)

Light sensitivity, also known as photophobia, refers to an abnormal sensitivity to light. This condition can be associated with vestibular disorders such as vestibular migraines and Meniere’s disease, as well as concussions. The relationship between vestibular disorders and light sensitivity may be attributed to several factors:

• Neural Connections: The vestibular system is closely interconnected with other sensory systems, including vision. Dysfunction in the vestibular system may lead to disruptions in neural processing, affecting how the brain interprets visual stimuli, potentially causing sensitivity to light.

• Central Nervous System Involvement: Vestibular disorders often involve the central nervous system, including the brain. The central nervous system plays a crucial role in processing sensory information, and disruptions in this processing may contribute to heightened sensitivity to light.

• Elevated Sympathetic Nervous System (SNS) Response: The SNS is one of the two divisions of the autonomic nervous system, which controls involuntary bodily functions, including the "fight or flight" response. Activation of this system can lead to pupillary reflex and heightened light sensitivity.

• Overstimulation and Disorientation: Individuals with vestibular disorders may experience difficulties in processing sensory input, leading to a sense of disorientation. Exposure to bright lights can exacerbate these sensations and contribute to discomfort and increased sensitivity.

• Anxiety and Stress: Vestibular disorders can be challenging to cope with, and individuals may experience heightened levels of stress and anxiety. Both stress and anxiety can contribute to an increased sensitivity to light.

Dark Adaptation

The typical response of many people dealing with light sensitivity is to avoid bright lights and sun. The problem with this approach, however, is that avoidance of light stimuli can lead to something called dark adaptation. Dark adaptation is the training of your eyes to adapt to darkness. It is a normal process that allows us some visibility to the dark, but is a flexible system that adjusts back when exposed to daylight again. If we spend a lot of time in the dark on a regular basis however, your eyes can adapt on a more permanent basis. Although being in the dark provides relief at the moment, this long term dark adaptation will lead to even more light sensitivity, even when exposed to normal lighting conditions.

Using Graded Exposure

To work on light sensitivity, we can use a concept called Graded Exposure. This involves gradual exposure to activities in low lighting for short durations and then building up from there. As you find the light less bothersome, you can increase not only the brightness of the light but also your time in those environments. Being conscious of other stimulating factors is important when working on this – highly busy environments will pose an extra level of challenge compared to those with less stimuli, so keep this in mind. In addition, bright lighting that is also flickering will provide an extra level of challenge, so keep this as an advanced level of exposure.  

Tools and Tips to Help with Light Sensitvity

Tools also exists on the market to help us during Graded Exposure. These can help significantly, and we recommend they be used early on in recovery to avoid dark adaptation. Let’s discuss the various options:

Tint Lenses

The FL-41 tint is a rose-coloured tint that filter the blue-green light wavelength which many people tend to be sensitive too. This tint can be applied to prescription glasses or be purchased as stand alone glasses. Migraine glasses such as TheraSpecs are examples of ready to go glasses like this. Avulux and Axon Optics on the other hand block LED blue light but spare the green light wavelength, which research shows could have a soothing effect. 

Screen Filters

Many adjustments can be made to your devices to help make the screens more tolerable. Here are a few:

• Add anti-glare screen covers to your devices to reduce the bounce back of light from above.

• Reduce screen brightness and contrast in your device settings.

• Apply a colour tint to your device. This can often be found under the “Accessibility” area in your device settings. Apply a colour tint that is similar to the FL-41 tint and vary the intensity of that tint as much as you need.

• Use Night Mode – this automatically adjusts the colour hue as well of your screen and is a common feature built into many devices. You can apply night mode just in the evenings, or all day if it’s soothing for you.

Green Lamps

Research has shown that people who are light sensitive are most comfortable with wavelengths between 480 and 590nm, which is a green hue. As discucsed above, many migraine glasses are adjusting to allow this light though, and products are also coming on the market providing only this green hue to symptom management. Adding a green light such as the Allay Lamp may allow you to feel more comfortable in room light and can be used as a tool with graded exposure. The Allay Lamp does not ship outside of the USA, so we have found alternatives such as the Hooga Lamp which can ship in Canada. 

Brimmed Hats

Many light sources come from above our heads, so to help get used to general lighting without being exposed to the light source itself, try wearing a brimmed hat, such as a baseball hat. This is especially useful for gradual exposure to sunlight.

Eye Health

Dry eyes can contribute to light sensitivity so use lubricating eye drops (artificial tears) as recommended by your optometrist.

Above all else, addressing the underlying cause of your light sensitivity is the most important for long term results. Often we can pair strategies as discussed in the article with specific home exercises to improve your vestibular system, reduce visual dependency and sensitivity, improve SNS response, and address specific goals you set out with you your therapist. Working with a vestibular physiotherapist can help in this area, so please reach out to us at Healing Vertigo if you have any questions, we are always here to help.