Autism Study Aids Understanding of Brain-Retina Links

Can activating a brain chemical help normalize the visual processing capabilities of those on the autism spectrum?

Scientists say, “Quite possibly, yes,” according to Deborah Zelinsky OD, commenting on a study just published in the January 2022 edition of the journal Science Translational Medicine. “The authors’ results bring us another step closer to understanding the complex interconnections and interplay between the grey matter in the brain and sensory systems, particularly the eyes.”

In their study, investigators determined that stimulation of a chemical messenger, gamma-aminobutyric acid (GABA), in the brain can potentially reduce sensory sensitivities in autistic individuals, allowing them to process visual information more like neurotypical individuals.

The term “visual processing” refers to the brain’s almost-instantaneous ability – consciously and non-consciously – to take in external sensory signals (from eyesight, hearing, smell, taste, and touch), combine them with a person’s internal sensory signals (such as head position and muscle tension) and then synthesize – process — the information, allowing a person to react and respond normally to his or her environment.

“People can become confused about their surrounding environment, have limited perception and awareness, and experience difficulties in learning, attention, reading, cognition, posture, and balance when brain circuitry is not synchronized,” Dr. Zelinsky says.

As founder and executive director of research at the Northbrook, Ill.-based Mind-Eye Institute, Dr. Zelinsky has long ascribed critical importance to the role of the retina as a component of the central nervous system.

“The retina serves as a primary portal through which environmental signals in the form of light enter and then convert into electrical signals that propagate through neurons and interact with critical brain structures, including the hypothalamus and brainstem,” she explains. When looking at indirect connections, there are many more. “The implication is stimulation of the retina can impact regulation of basic physical, physiological, and even psychological processes, including motor control, posture, emotions, and perception. At the retinal level, signals are sorted out before leaving the eye for further brain processing.”

She and her Mind-Eye team have achieved worldwide recognition doing just that, stimulating the retina through use of therapeutic eyeglasses, lenses, prisms, and filters that vary the amount, intensity, and angle of light passing through it. “By manipulating light with brain glasses, we are often able to reduce symptoms and restore comfort to patients who need to rebuild visual processing skills compromised by neurological disorders like head injury and stroke or develop new visual processing capabilities in patients with dyslexia, attention deficit hyperactivity disorder (ADHD), and autism,” she explains.

Because of the intricate links between the brain and the retina, Dr. Zelinsky says she is not surprised that this latest autism study offers additional insight into how regulation of brain chemicals like GABA can affect a person’s processing of visual stimuli.

“Visual processing skills are essential to all aspects of quality life,” Dr. Zelinsky emphasizes. “If central and peripheral eyesight fail to connect and interact properly or if eyesight and listening abilities are uncoordinated, then a patient’s ability to visualize is affected, as is the amount of energy expended.”

Autism spectrum disorder (ASD) is an umbrella term, encompassing a continuum of various conditions, including Asperger syndrome, autism, and pervasive developmental disorder. It often develops by age 3, usually lasts a lifetime, and results in visual processing difficulties that can lead to developmental delays, deficits in communication and emotional skills, behavioral problems, and difficulties with social interaction. Scientists believe genetics plays a role in some affected patients, but differences in brain function, structure or other neurological issues may be underlying causes as well.

Among specific manifestations of ASD are language deficits or use of language in unusual ways or patterns, impulsiveness, lack of awareness or responsiveness to what is occurring in the surrounding environment, repetitive or obsessive behaviors, difficulties interacting or communicating with others, abnormal moods or states of mind, and eating and sleeping problems.

The lead author on a study published online said his group’s research “pioneers a new way to assess whether there is a difference in the function of brain chemical pathways responsible for processing sensory information in autism and whether those pathways can be altered.”

The Mind-Eye Institute is positioned to demonstrate to them that individualized eyeglasses are one way to alter those pathways, Dr. Zelinsky says.