‘Retina May Prove ‘Poor Man’s MRI’ for Diagnosing Disease

The eye does not have to be open for the retina to stimulate brain activity.

“Light traveling through a closed eyelid [actually] affects spatial perception and brain processing,” Deborah Zelinsky, OD, said in a keynote address — Inclusion of Brain Mapping and Retinal Neuromodulation into Eye Care Policy: Here Today, But Where Tomorrow. She delivered her speech during the recent 19th Annual Congress of the Society for Brain Mapping and Therapeutics (SBMT) in Los Angeles. Dr. Zelinsky is founder and research director of the Northbrook, Ill.-based Mind-Eye Institute and is internationally known for her understanding and studies of the retina as a critical component of the central nervous system.

“Retinal stimulation [with light] impacts systems other than [simply] eyesight,” Dr. Zelinsky told her audience. “These non-image-forming pathways link directly with brain processing.”

Because of her groundbreaking studies, unique testing methods, and clinical applications of optometry, Dr. Zelinsky was presented the SBMT’s Golden Axon Award at the SBMT Congress. The award recognizes scientists, academicians, community leaders, members of the media, and others in the public sector who have “inspired an enthusiastic interest in science, technology, and medicine,” according to the SBMT. The word “axon” refers to the cell fiber in the brain responsible for sending communication impulses to other cells.

The Mind-Eye Institute is internationally known for its use of therapeutic eyeglasses and other advanced optometric tools to manipulate the amount, angle, and intensity of light passing through the retina. Such manipulation creates changes in the brains of patients suffering the symptoms of traumatic head injury, concussion, stroke, and neurological disorders. Retinal stimulation also has proven effective in building undeveloped visual processing skills in children – and adults – with autism spectrum disorder, attention deficit hyperactivity disorder, and other learning, socialization, and behavioral difficulties.

Environmental signals in the form of light enter the retina and convert into electrical signals, which propagate through neurons and interact with key brain structures. Retinal signals affect not just the visual cortex but other, significant regions of the brain as well, linking with structures such as the limbic system, the cerebellum, midbrain, thalamus, hypothalamus, and brainstem, Dr. Zelinsky told her SBMT audience.

“The right mix of prescriptive lenses, filters, and prisms modifies the distribution of light on the retina. These modifications occur in both space and time, thereby altering the dynamic relationship between the mind’s retinal inputs and the body’s internal reactions and responses. The implication is that this retinal stimulation can promote changes in basic physical, physiological, and even psychological systems involved in motor control, posture, emotion, and thinking,” Dr Zelinsky said.

Dr. Zelinsky’s speech also touched on a theme common to many of her discussions — that 160-year-old standard optometry practices must be updated to bring them more in line with 21st century advancements in knowledge of the retina and retinal testing techniques.

“Standard eye evaluations continue to be fine for the typical patient. However, they are not sufficient for patients with brain injuries, autism, autonomic dysfunction, or even long COVID. The standard eye test is based primarily on evaluating central eyesight by having a patient fix conscious attention on a non-moving target, such as an eye chart. But general awareness of – and comfort with — today’s fast-paced environment is highly dependent on properly functioning peripheral eyesight. Modern society is awash in moving targets – from signs, lights and other vehicles whizzing past us in traffic to ever-changing GPS navigation screens and words rolling in and out of sight on scrolling web pages,” she indicated.

“We use peripheral and central eyesight in tandem to scan and shift our gaze from place to place. Only about six percent of our surrounding awareness comes from conscious attention on specific objects. Most environmental signals passing through our retinas emanate from peripheral space – the space all around us. This peripheral input is typically taken for granted, but after brain injury, certain cases of COVID, and autonomic dysfunction, it is not efficiently functioning.”

Unfortunately, despite its critical role in a brain injured person’s ability to perceive and function comfortably, peripheral eyesight – and its impact on brain function – remains largely untested during normal optometric evaluations, Dr. Zelinsky adds. “We do not normally consider the importance of peripheral eyesight in our lives until a brain injury or other neurological disorder disrupts it.”

Depending on a person’s surrounding space and state of mind, the brain will usually turn on or tune out peripheral/background auditory and visual signals and engage or disengage eye-aiming at targets. When intact, such brain processing enables people to have some internal systems (such as balance and posture) running automatically. This “cruise control” allows a person to respond appropriately to the external world, she states. “However, if brain circuitry is out of sync because it has been disrupted – or, in the case, of younger children, perhaps under-developed — people become confused about their surrounding environment and may exhibit inappropriate reactions and responses.”

Dr. Zelinsky has long concurred with other scientists that the retina is a “window to the brain” and could serve as a “poor man’s MRI.”

Because the retina is part of the brain, “I propose that mapping the brain onto the retina could then be used to zero in on brain injury,” thus “facilitating and individualizing rehabilitation,” Dr. Zelinsky said in her address. The latest “research indicates retinal degeneration reflects similar degeneration occurring in the brain. Studies are showing retinal changes that mirror brain changes in patients with Alzheimer’s disease, multiple sclerosis, schizophrenia, and Parkinson’s.

“The retina tells a lot about a person’s overall health. That is why, perhaps, eye care practitioners may eventually become the professional patients seek first for diagnosis of a variety of disorders, including early onset Alzheimer’s disease, high blood pressure, cardiovascular issues, diabetes, or other disorders,” she suggested, when musing about the 22nd Century.

“In fact, it would make sense that retinal neuromodulation of brain activity through non-invasive stimulation of the eye — alone or in combination with other therapies — will prove clinically effective in addressing a host of neurodegenerative diseases, mental illnesses, autism, metabolic disorders, as well as dysfunctions in circadian rhythm, limbic, and endocrine systems.”