Optometry Podcast: The Physiological, Social and Emotional Effects of Light Sensitivity

This podcast is in partnership with Transitions Optical

How does daily exposure to light impact visual performance, general health, and wellbeing? We called in the experts to address this topic that is so important to our patients’ visual comfort. Dr. Coralie Barrau, Senior Scientist of Photobiology with Essilor, is a physicist who researches how light impacts our ocular, mental and systemic health. Chris King is the Global Marketing Manager for Transitions Optical who collaborates with leading experts in the field of research and development and helps bring this scientific information to the public. 

Scientists at Transitions recently published a white paper on Sensitivity to Light and on today’s podcast episode we break down the pertinent findings. Research shows that eyecare providers are falling short at dialogue and action for the very common issue of glare and light discomfort that patients suffer from. One of the key insights from the study is that 9 out of 10 people say they experience light sensitivity. When the degree of sensitivity is measured, approximately 1 in 3 people would be classified as highly light sensitive. Concerningly, only 1 in 10 patients worldwide actually wear lens technology that addresses these issues, however. 

Dr. Coralie Barrau, Senior Scientist of Photobiology with Essilor

The type of environment we live and work in has drastically changed over the last two decades. Patients today are surrounded by artificial light sources: digital screens, fluorescent lighting, LED lighting. “The former balance of natural and artificial light has been totally disrupted,” states Barrau. “We are now overexposed day and night to artificial lights and LED lighting, and we really lack the benefits of natural light at specific moments of the day. Instead of aligning behavioral and physiological processes to natural solar cycles, individuals today respond to artificial light cycles to train our biological rhythms.” The result of this artificial light environment?  Increased sensitivity to light, poorer biorhythms, and a de-synchronization of our biological clocks. 

The white paper takes a holistic approach to the science of light sensitivity, including the physiological aspects of how the eye and brain interact with light and the social and emotional implications of light exposure. To classify light sources and discomfort, researchers looked at 4 dimensions of light: intensity, spectrum (color), temporality, and spatial distribution. 

Light Intensity

“The more intense the light, the brighter the light and the more discomfort and visual disruption experienced,” Barrau explains. Our eye adjusts to brighter light by constricting the pupil, squinting, and rapidly blinking. 


Blue light, ranging from 380 to 500 nm, is the most energetic part of visible light entering the retina. Increasing experimental evidence has indicated that prolonged exposure to blue light contributes to retinal ageing and may cause or enhance retinal damage. Particularly, it has been demonstrated that exposure to blue-violet light between 415-455 nm can induce irreversible cell death in the outer retina in simulated moderate daylight conditions.  Beyond its cumulative effects on visual health, multiple scientific papers suggest blue light exposure increases glare. Filtering blue light may improve visual function in high glare situations.

Spatial Distribution

The spatial position of light sources and their size have a huge influence on the amount and quality of light received by our eyes. The smaller and closer the light source, the worse the discomfort glare. Take for example headlights, which can be particularly bothersome because of their size and close range to the observer.  


Our light environment is not static, it constantly changes over time. More recent exposures to changing brightness levels impact our eyes’ ability to adjust to new light levels. Our eyes tolerate changes to light less well after they have been exposed to recent changes in brightness level. For example many patients struggle with oncoming headlight glare sensitivity after being at work because they are going from looking at a bright screen to stepping outside in dim or dark lighting, and then seeing bright oncoming headlight glare in rapid succession. 

Researchers looked at how each of these 4 dimensions interact with our eye and brain. In doing so they identified a few key questions that eyecare providers can ask patients to discover any underlying light sensitivity issues in their daily lives. They found that wording is key to connecting the issues that patients are having with light sensitivity as an underlying cause

  1. Do you squint when you walk around in bright sunlight?
  2. Does light often make you feel uncomfortable while driving at night?
  3. Are you bothered by harsh indoor lights?
  4. Do you often feel like your eyes  become strained while (or after) using a computer? 
  5. If you’ve been outdoors on a bright day, do you find it difficult to see properly for a few moments after you’ve gone indoors?
  6. Do you sometimes dim your smartphone screen because you’re bothered by the brightness of the light? 

“People who experience sensitivity to light are impacted not only physically, but emotionally, professionally and socially,” shares King. “A loss of visual performance or light associated discomfort can impact daily life.” Research shows 86% of working Americans experience it in the workplace and 74% say sensitivity to light negatively impacts their ability to do their jobs.” In patients with severe light sensitivity, the effect can be withdrawal from social interactions and significant pain. King shares the story of a patient he spoke with in researching this topic who was so bothered by ocular pain with light exposure that she became isolated. After a doctor diagnosed her with light sensitivity and prescribed XTRActive Transitions lenses she was able to see an immediate improvement not just on pain, but in the enjoyment of activities in her daily life. 

To learn more about this important research and what it means to your patients, head here

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