Doctors Capture Cherenkov Light Phenomenon Generated Inside Eyeball For First Time

by : Cameron Frew on : 10 Jan 2020 15:09
Doctors Capture Cherenkov Light Phenomenon Generated Inside Eyeball For First TimeDoctors Capture Cherenkov Light Phenomenon Generated Inside Eyeball For First TimeLesley Jarvis

For decades, Cherenkov light has remained a medical enigma. Now, scientists have captured it on camera for the first time.


Cancer patients undergoing radiotherapy have reported a certain strange phenomenon for years: flashes of bright or blue light, simultaneous with radiation delivery.

It’s been reported to occur even when patients have their eyes closed, even just for a fraction of a second. However, it’s largely remained a mystery until now.

Cherenkov Light Eye 3Cherenkov Light Eye 3Lesley Jarvis

As per IFLScience, Cherenkov light ‘is electromagnetic radiation that’s emitted when a charged particle passes through matter at a greater speed than the speed of light within that medium, producing an effect like a sonic boom, which occurs when, for example, a plane travels faster than the speed of sound’.


While the sensation in humans has been relatively well-documented, it’s been difficulty to secure any evidence of it actually occurring.

In order to solve the problem of Cherenkov light, a team of researchers at Dartmouth’s and Dartmouth-Hitchcock’s Norris Cotton Cancer Center led by radiation oncologist Lesley Jarvis, MD, PhD and Irwin Tendler, MEng got together – their study was then published the International Journal of Radiation Oncology.

Cherenkov light EyeCherenkov light EyeLesley Jarvis

By using CDose camera imaging system, specially designed to view light emissions from biological systems, the researchers managed to capture the glowing light.

Tendler, of Dartmouth College explained further in a statement:

Our newest data is exciting because for the first time, light emission from the eye of a patient undergoing radiotherapy was captured. This data is also the first instance of evidence directly supporting that there is enough light produced inside the eye to cause a visual sensation and that this light resembles Cherenkov emission.

As the radiation beam passes through the eye, light is generated within the vitreous fluid. Our real-time data rigorously showed that the amount of light produced is sufficient to elicit a visual sensation – a topic that has been debated in the literature.

By analysing the spectral composition, we also show that this emission can be classified as Cherenkov light – again, another contested point in the literature.

As light emission from the eye is incredibly subtle, it had been nigh-on impossible to detect until recently. It’s hoped that the new research and imaging system will benefit radiation therapy in the future.

Cherenkov Light Eye 2Cherenkov Light Eye 2Lesley Jarvis

Tendler added: 

In the case that the eye is a target, the method could provide confirmation of beam delivery; in the case that this is unintentional, it can provide evidence of an error or near miss – as a safety check.

The researchers’ next steps are to establish whether there’s a link between ocular Cherenkov light and long-term visual effects.

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Cameron Frew

After graduating from Glasgow Caledonian University with an NCTJ and BCTJ-accredited Multimedia Journalism degree, Cameron ventured into the world of print journalism at The National, while also working as a freelance film journalist on the side, becoming an accredited Rotten Tomatoes critic in the process. He's now left his Scottish homelands and took up residence at UNILAD as a journalist.

Topics: Science, Cancer, Cherenkov Light, eyes, Radiotherapy


IFLScience and 1 other
  1. IFLScience

    Doctors Capture Cherenkov Light Being Generated Inside Patient's Eyeball For The First Time

  2. International Journal of Radiation Oncology

    Experimentally Observed Cherenkov Light Generation in the Eye During Radiation Therapy