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Media, Additional Research, Research, Visual Processing

Light, Retina, and Metabolism of Glucose Are Linked

Latest Study Underscores Mind-Eye’s Use of Light to Stimulate Retina

Could artificial light, especially blue wavelength, impair the body’s metabolism of glucose by affecting the neural circuitry between the eye’s retina, the hypothalamus in the brain, and fatty tissue?

The latest study, published in a 2023 edition of the journal Cell, suggests yes and offers additional evidence for the Mind Eye Institute’s longtime contention that light affects major physiological and neurological systems in the body, including metabolism.
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What is Glucose?

Glucose is a simple carbohydrate essential to all human life. It is the main source of energy for the brain and the muscles. Impaired glucose tolerance raises blood sugar levels – a prediabetic state. If not appropriately treated, the condition can lead to diabetes.

The Mind-Eye Institute uses light to stimulate the retina and create changes in the brain. By altering the amount, intensity and angle of light passing through the retina, the Mind-Eye team has been able to bring symptomatic relief to patients who suffer from the effects of traumatic head injury, concussion, stroke, and neurological disorders.

“The retina is composed of brain tissue and plays a crucial role as part of the central nervous system. It acts as a primary portal for information to the brain,” says Deborah Zelinsky OD, an optometrist world-renowned for her work in retinal processing and the founder and research director of the Mind-Eye Institute in Northbrook, Illinois.

“Past research has shown a link between light, the retina, and metabolic disorders, specifically an association between artificial light, glucose regulation, and increased risks for developing obesity and diabetes. This most recent study now highlights the neurological pathways that artificial light can affect, causing changes in the normal glucose metabolism,” Dr. Zelinsky says.

About the Latest Study of Light and Glucose

Working with mice, authors of the article in Cell determined that activated photosensitive retinal cells innervate the hypothalamus and eventually affect the neurons that communicate with the body’s adipose (fatty) tissue. “Light activation of this neural circuit directly blocks adaptive thermogenesis (production of heat) in brown adipose tissue, thereby decreasing glucose tolerance,” the scientists report.

“These findings are not unexpected,” emphasizes Dr. Zelinsky. “We have long known environmental signals (in the form of light) enter the retina and convert to electrical signals, which propagate through neurons and interact with key brain structures. These retinal signals affect not only the visual cortex but other, significant regions of the brain as well, linking with structures like the midbrain, thalamus, hypothalamus, and brainstem.”

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“Artificial light increases risks for obesity and diabetes." -Deborah Zelinsky, OD

Importance of Therapeutic Eyeglasses

That is why the right mix of prescriptive lenses, filters, and prisms can remodel the spatial and temporal distribution of light on the retina, thereby modifying the dynamic relationship between the mind’s visual inputs and the body’s internal responses, she explains. “The implication is that this retinal stimulation can intentionally promote customized changes in basic physical, physiological, and even psychological systems involved in motor control, posture, emotion, and decision-making abilities,” Dr. Zelinsky indicates.

While artificial lighting has an apparent negative effect on glucose metabolism, could stimulation of the retina using natural sunlight prove an effective approach for normalizing metabolic function?

"Yes," Dr. Zelinsky says. 

She points out that the authors of the study in Cell say their findings do “suggest” a potential prevention and treatment strategy for managing glucose metabolic disorders. Such a strategy might involve manipulation of the way natural light stimulates the retina, Dr. Zelinsky states.

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Artificial Light a Growing Public Health Problem

Many scientists call the extensive use of artificial light, particularly during the evening and night hours, a public health problem, which must be better managed. Of special concern is the proliferation of high-energy blue light waves like those emitted by diode screens in mobile phones and computers.

Blue light is known to interfere with circadian rhythm and sleep – the reason sleep experts suggest electronic devices be turned off at least an hour or two before bedtime. Some researchers even say blue light can cause eye damage, including macular degeneration. That is why a yellowish tint is placed into cataract implants in order to block out blue wavelengths and ward off macular degeneration.

“Continuing advancements in our understanding of the retina and in the technology required to evaluate it could one day make optometrists the go-to professionals for early detection and diagnosis of a host of systemic disorders, including metabolic dysfunction,” Dr. Zelinsky states.