Predicting Dementia Through the Retina... "Increased Risk When the Macular 'Nerve Fiber Layer' Is Thin"

Bundang Seoul National University Hospital Professors Woo Se-jun and Kim Ki-woong Research Team
Large-Scale Retinal Study Highlighting Dementia Predictors
Bottom 25% Neurofiber Layer Thickness Increases Dementia Risk Fivefold

Professor Woo Se-jun (left), Department of Ophthalmology, Seoul National University Bundang Hospital, and Professor Kim Ki-woong, Department of Psychiatry.

[Asia Economy Reporter Lee Gwan-joo] Professor Woo Se-jun of the Department of Ophthalmology and Professor Kim Ki-woong of the Department of Psychiatry at Bundang Seoul National University Hospital announced on the 26th that their research team revealed through a large-scale cohort study that the thinner the thickness of the retinal nerve fiber layer in the macula, the higher the risk of experiencing cognitive impairment in the future.

The retina is the innermost membrane of nerve cells in our eyes, responsible for detecting light and processing and integrating visual information to transmit it to the brain. As the body ages, the retina becomes thinner, and the function of the optic nerve also deteriorates. Recently, the association between decreased retinal layer thickness and cognitive decline has been identified, drawing attention in academia as a factor for evaluating dementia.

The research team conducted a study on 430 elderly residents of Seongnam City, measuring their initial retinal thickness and analyzing differences in cognitive function test results regularly conducted over the following five years according to retinal thickness. The precise analysis of retinal thickness was performed using the ‘Optical Coherence Tomography’ method. As a result, among various retinal layers, when the thickness of the macular Retinal Nerve Fiber Layer was in the lowest 25% (231 micrometers or less), the probability of developing dementia was found to be more than five times higher. Other retinal layers did not show a clear association with future cognitive decline.

The cognitive function scores of elderly individuals with thinner retinal nerve fiber layer thickness (orange) are lower than those of elderly individuals with thicker layers (blue), and the rate of decline is also steeper.

Specifically, elderly individuals with thinner nerve fiber layers started with an average cognitive function evaluation score (CERAD-TS) of 65.4 points initially, decreasing by 3.79 points annually, showing lower cognitive function and a steeper decline compared to the group with thicker nerve fiber layers (starting at 68.5 points, decreasing by 2.42 points annually). This pattern was also consistent in another cognitive function assessment tool, the MMSE test. Consequently, the group with thinner macular nerve fiber layers had a 52.7% probability of developing mild cognitive impairment or Alzheimer’s disease in the future, significantly exceeding the control group’s prevalence rate of 11.3%, indicating a risk of cognitive impairment more than five times higher.

This study is significant as the first in Korea to reveal the relationship between cognitive function and retinal structure in the elderly population and as the world’s first study to clarify the relationship between retinal structure and future cognitive decline through long-term follow-up observation.

Professor Woo stated, “This study demonstrated that measuring the thickness of the macular nerve fiber layer can predict the risk of cognitive impairment,” adding, “There is also a high possibility of utilizing this in clinical settings for early diagnosis and treatment of cognitive impairment.” Professor Kim explained, “Various factors related to cognitive impairments such as Alzheimer’s disease are being identified,” and “If the mechanism by which retinal structure affects cognitive function is elucidated, it will greatly aid the development of treatments.”

The results of this study were recently published in the world-renowned journal, ‘JAMA Ophthalmology.’