dvanced neuro-ophthalmic research has identified changes in the condition and function of the eye that could lead to enhanced diagnosis and management of neurological disease and brain injury.
Research into optic neuritis as a manifestation of multiple sclerosis (MS) took a major step forward in 2018 with the publication of a pilot study by NYU Langone researchers establishing a threshold for the amount of retinal thinning considered predictive of an MS-related lesion in the optic nerve, the pathway connecting the eye with the rest of the brain.
Using optical coherence tomography (OCT), a high-resolution retinal scanning technique pioneered by investigators at NYU Langone, the new study builds on earlier research aimed at identifying patients with a history of optic neuritis. The higher resolution of OCT scans may be better able to detect both asymptomatic and symptomatic MS-related optic nerve lesions—a defining MS symptom currently omitted from standard diagnostic criteria—and measure the progression of MS and response to treatment over time.
The 2018 study, published in the Journal of Neuro-Ophthalmology, compared OCT scans of 124 individuals diagnosed with MS to scans of healthy controls.
It found that an inter-eye difference of five to six microns in retinal nerve fiber layer thickness most closely correlated with patients who had an optic nerve lesion, which was defined for the study as a clinical history of prior optic neuritis.
This NYU Langone–based investigation led to an international, multisite study of 1,500 patients with MS, which confirmed these inter-eye difference thresholds for the identification of an optic nerve lesion within a larger and more diverse study cohort.
“Virtually every patient with MS eventually develops optic nerve lesions—which is why we feel strongly that the presence of such lesions should be one of the imaging criteria used in diagnosing MS,” explains Steven L. Galetta, MD, the Philip K. Moskowitz, MD, Professor and Chair of Neurology and professor of neurology and ophthalmology. “The next step is to see how our OCT data fares in modeling and predicting who ultimately gets MS by establishing a meaningful benchmark for retinal nerve thickness and monitoring the outcomes of those with clinically isolated demyelinating syndromes.”
Using OCT to Diagnose and Monitor Other Neurological Disorders
In light of OCT’s relative ease of use and low cost as a diagnostic tool, the division is expanding the applications of OCT to the evaluation of other conditions, such as suspected chronic traumatic encephalopathy (CTE) in contact sport athletes.
“The goal is to determine whether this visual pathway can serve as a potential living biomarker for CTE or cognitive decline among those who have a history of contact sports exposure,” notes Laura J. Balcer, MD, MSCE, professor of neurology, ophthalmology, and population health, and vice chair of the Department of Neurology.
This research joins other ongoing OCT studies of patients with Parkinson’s disease and Alzheimer’s disease, all with the common goal of providing new insight into the effects of these disorders on the eye and visual pathway, and potentially helping predict disease progression.
MULES Adds to Concussion Assessment on the Sidelines
As concussion continues to grow as a concern in youth, collegiate, and professional sports, the Mobile Universal Lexicon Evaluation System (MULES), a vision-based picture naming test developed by doctors in NYU Langone’s Neuro-Ophthalmology Program, is proving to be an effective tool for the sideline assessment of concussion and it could be effective in identifying other neurodegenerative conditions as well.
Designed as a series of 54 grouped color photographs that integrate color perception, eye movements, and contextual object identification, MULES is a subtype of the rapid automatic naming measures that have been used for more than 80 years to capture vision-based aspects of cognition.
“We’re employing the test on a research basis with a number of local athletes,” notes Dr. Galetta. “By comparing sideline performance with an athlete’s preseason score, we’ve found that it identifies concussion with a high level of sensitivity.”
MULES also has potential as a vision-based assessment tool for other neurological disorders since it captures a wide distribution of neural networks, involving color vision, object recognition and categorization, and speed of object identification.
One study, published in 2018 in the Journal of the Neurological Sciences, correlated MULES performance with vision changes found in patients with MS. The study found a link between slower MULES picture-naming times and low-contrast letter acuity, the perception of gray letters on a white background—established for two decades as a marker of MS-related visual dysfunction.
Researchers are now studying the effectiveness of MULES in Parkinson’s and Alzheimer’s diseases, and investigators in the Eye Movement Testing Lab have added the test to their groundbreaking repository of data linking eye movement abnormalities with various neurological conditions to look for new patterns and potential diagnostic clues.
The expanding applicability of vision-related evaluation tools suggests that changes in visual structure and function truly reflect what is happening with the rest of the patient’s nervous system. “The eyes are a window into the brain, and we’re continuing to explore that connection,” notes Dr. Balcer.