When the Lights Went On: A Scientist's Journey from Classroom to Advocacy

The pain hit instantly. Dr. Jennifer Hackett had walked into hundreds of classrooms over her teaching career, but this newly renovated space with LED lights was different. Within seconds, she felt what she describes as "a massive jolt of pain behind my right eye that felt like a bee sting that didn't stop."

[00:15:02] Most people might have assumed it was a headache and moved on. But Hackett isn't most people. With a PhD in molecular biology from Johns Hopkins and postdoctoral training at Harvard, she approached the problem like the scientist she is.

From Nobel Prize Labs to High School Hallways

[00:05:17] Hackett's path to that painful moment began in some of science's most prestigious labs. She worked with Carol Greider, who would later win the Nobel Prize for discovering telomerase, studying the protective caps on chromosomes that prevent DNA from unraveling. After graduate school, she moved to Harvard for postdoctoral research on genome screening techniques.

[00:13:35] But despite working on cutting-edge science, Hackett found herself drawn to weekend volunteer work with children. "I realized I was much more excited to wake up super early on a Saturday morning to go do arts and crafts projects with children at a shelter than I was to be doing the nitty gritty of the lab work," she explains.

The transition from research to teaching wasn't just a career change—it was preparation for the detective work that would define her next chapter.

When Your Brain Stops Working

[00:19:34] The symptoms that followed Hackett's LED exposure weren't just about pain. Within days of working under the new lights, she experienced something that terrified her: she couldn't add simple numbers anymore. After grading papers for over a decade without a calculator, she found herself unable to sum five single-digit scores.

[00:20:15] "I couldn't add these numbers. And I'm like, okay, this normal strategy I always use wasn't working. I'm like, let me do it like one by one and keep my finger in place and see if I can do it this way. And I couldn't do it. Once I had summed two numbers, I couldn't remember the sum to then add the third number on."

Her scientific training kicked in. She recognized the symptoms as severe short-term memory impairment, similar to what she'd observed in students with concussions.

Finding Validation in Unexpected Places

[00:24:08] When Hackett finally saw a neurologist in January 2019, the response surprised her. "Oh yeah, lights injure people and give them headaches. Let me write you a note that says you can keep the light switch off." The casual acknowledgment suggested this wasn't an isolated case.

Even more telling: the office staff had their own slang term for it—"LED allergy."

[00:26:17] But the real breakthrough came during testing with a neuro-ophthalmologist. Under LED lights, the visual field test showed peripheral blindness in her right eye. When they repeated the test with the lights off, both eyes tested normal. It was objective, measurable proof that something physical was happening in response to the lights.

The Engineer's Approach to Light

[00:29:07] Hackett began systematically testing hypotheses. Blue light? She'd worked with blue LED devices for years in teaching genetics without problems. Brightness? Sunglasses helped minimally. Then she discovered Arnold Wilkins' research on flicker.

[00:33:50] Most people don't realize that LED lights flicker. Unlike steady sunlight, AC-powered LEDs pulse on and off, typically 120 times per second. While incandescent bulbs create gentle, wave-like variations in brightness, LEDs can switch between full brightness and complete darkness in sharp, rectangular patterns.

[00:40:16] Using fidget spinners as makeshift flicker detectors, Hackett found she could easily see the stroboscopic effects from lights that hurt her. The lights that didn't cause symptoms showed little to no visible flicker.

Professional Investigation

[00:42:35] Determined to get real data, Hackett purchased professional flicker measurement equipment—an $800 device that normally costs $2,500 new. She began systematically documenting the flicker characteristics of lights that injured her versus those that didn't.

[00:43:27] Her hypothesis seemed confirmed: lights with severe flicker hurt her, and those without flicker generally didn't. But then she discovered a middle category—lights with subtle flicker that still caused symptoms, though less severe ones.

The pattern suggested that flicker was indeed the culprit, but the relationship was more complex than a simple on/off switch.

A Problem Bigger Than One Person

[00:59:09] The timeline troubled Hackett. LED adoption accelerated in the early 2010s, coinciding with documented increases in anxiety rates and declining academic performance among students. Could invisible flicker be affecting people who don't even realize it?

[01:27:18] Recent research supports her concerns. A 2024 study by Naomi Miller at Pacific Northwest National Laboratory found that 40% of migraine sufferers developed headaches after controlled exposure to common LED lighting, compared to only 8% of non-migraine participants.

From Personal Crisis to System Change

[01:30:07] Today, Hackett can't use screens or enter most buildings safely. She relies on phone calls instead of emails and depends on neighbors to help with tasks that require exposure to LED lights. Yet she maintains remarkable optimism about her work.

[01:30:49] Her current focus isn't on individual accommodation but systematic change. She's identified specific research needs: partnerships with industry for controlled testing, collaboration with medical researchers, and development of detection methods that don't require continuous self-injury.

[01:12:32] Most importantly, she's documented everything. Her website contains comprehensive data correlating flicker measurements with symptom severity—information that could inform the larger-scale studies she believes are necessary.

The Path Forward

The moment that changed everything for Hackett was walking into a classroom with LED lights. But the change she's working toward is much larger: transforming how we understand the intersection of lighting technology and human health.

Her approach—systematic investigation, professional measurement, open data sharing—demonstrates how individual expertise can contribute to broader scientific understanding. The question now is whether the research community will build on the foundation she's created.

The lights that injured her are still there. But the data she's collected might help ensure that the next generation of LED technology is designed with human biology in mind.

Listen to the full episode: https://creators.spotify.com/pod/profile/shannon-lantzy

Jenny can be reached through flickersense.org

This content was repurposed from the original podcast discussion by a genAI prompt.