Dr. Dean Evan Hart Offers Expert Insight on Groundbreaking Eye-Brain Research Can Parkinson’s Disease (PD)—a condition most known for dysfunctional motor coordination, balance, and coordination—be detected through a routine eye exam? According to Dr. Dean Evan Hart, an optometrist and researcher in neurobiology, recent studies suggest that the eyes may provide critical early warning signs …
Dr. Dean Evan Hart Offers Expert Insight on Groundbreaking Eye-Brain Research
Can Parkinson’s Disease (PD)—a condition most known for dysfunctional motor coordination, balance, and coordination—be detected through a routine eye exam?
According to Dr. Dean Evan Hart, an optometrist and researcher in neurobiology, recent studies suggest that the eyes may provide critical early warning signs of Parkinson’s. While not directly involved in the study, Dr. Hart has reviewed the findings and believes they represent a significant step forward in connecting optometry and neurology.
The Study in Question
Published in the Journal of Parkinson’s Disease (2024), the research, conducted by Katie K.N. Tran, Pei Ying Lee, David I. Finkelstein, and others, explored whether Parkinson’s Disease could be detected through changes in retinal structure and visual function.
The study involved:
- 16 participants with PD and 21 healthy controls
- Testing over two visits span one week apart
- Tools commonly used in optometry, including OCT, ERG, and contrast sensitivity assessments
A central question: Can clinical biomarkers of PD be observed in the eye, even before motor symptoms begin?
Dr. Dean Evan Hart’s Take on the Findings
“This is exactly the type of research optometry and vision scientists need to pay attention to,” says Dr. Dean Evan Hart, who studies neurobiology and disease at NYU and has long advocated for a broader role for optometrists in systemic health care.
He explains that while the study was not optometry-led, the tools and findings fall directly within the scope of an optometrist’s clinical practice.
“We’ve long known that the retina is an extension of the brain and the central nervous system grey matter,” Hart says. “This research reinforces that concept by showing that changes in visual processing and retinal layers could act as biomarkers for Parkinson’s—years before the typical motor symptoms appear.”
What the Researchers Found
Visual Function:
The study revealed that PD participants had:
- Reduced contrast suppression (p = 0.0075)
- Lower macular field sensitivity (p = 0.016)
- Significantly poorer color vision (p = 0.0017)
“These visual impairments might not be obvious to the patient or even the optometrist without deeper testing,” Dr. Hart notes. “But they represent measurable changes in how the brain processes visual information.”
Retinal Structure:
Optical Coherence Tomography (OCT) identified:
- Thinning in the ganglion cell layer
- Reduction in the outer nuclear layer
- Changes approaching significance in the inner plexiform layer
“These structural changes are consistent with what we’d expect in a neurodegenerative disorder,” Hart adds. “And importantly, they’re detectable with equipment many optometrists already use.”
Retinal Function (ERG):
Electroretinography (ERG) testing showed:
- Photoreceptor dysfunction
- Bipolar cell abnormalities
- No improvement after L-DOPA medication, suggesting the dysfunction was not reversible in the short term
“That’s particularly interesting,” says Scientist Dean Evan Hart. “It suggests that these visual and retinal changes aren’t side effects of the medication, or temporary. They could be early signs of disease progression.”
Implications for Optometric Practice
While Dr. Hart cautions that optometrists are not in a position to diagnose Parkinson’s Disease, he believes this research highlights their potential role in early detection and referral.
“Time is limited during a routine eye exam,” he explains. “But for patients with subtle vision complaints—especially those with blurred near vision, contrast issues, or color perception problems—it might be worthwhile to look more closely.”
Final Thoughts from Dr. Dean Evan Hart
For Dr. Dean Evan Hart, the real takeaway is this: optometry and neurology need to communicate more effectively. The eye may not just be a window to the soul—it might also be an early warning system for brain diseases.
“Optometrists are on the front lines. We see patients before they ever show up to a neurologist,” Hart says. “With more education and collaboration, we could become a critical link in identifying neurodegenerative diseases such as Parkinson’s earlier than ever before.”
📚 Sources:
- Tran KKN, Lee PY, Finkelstein DI, et al. Journal of Parkinson’s Disease, 2024.
- Gibbon S, Breen DP, MacGillivray TJ. Movement Disorders, 2025.
- Armstrong RA. Clinical and Experimental Optometry, 91:129–138.
