Eyesight problems: may be the first signs of Alzheimer's

Two studies in quick succession show that the eyes are not only the mirror of the soul, as the saying goes, but also an early marker of pathological changes that affect the brain. Alzheimer’s and Parkinson’s diseases would be detectable in the eyes long before the first symptoms of these neurodegenerative diseases.

The decline in cognitive functions and visual acuity are two major problems associated with aging: it is expected that by 2050, the number of people affected by dementia will change from 53 at 132 million, while that of people with blindness will increase by 38 at 115 million.

Some observations suggest that these two conditions do not develop not independently, but could instead be linked. For example, autopsy studies carried out on people affected by Alzheimer’s disease have shown the presence of significant damage to the optic nerve and retina of these patients. A link between cognition and vision is also suggested by an analysis of data acquired by two large American studies (more than 29 participants in total), which shows that the risk of being affected by a loss of visual acuity is 2 to 3 times higher in people with cognitive dysfunction. However, these studies cannot determine whether vision loss is the cause or the consequence of the decline in cognitive functions.

Vision problems announce Alzheimer’s disease

image Les problèmes de vision annoncent la maladie d'Alzheimerimage Les problèmes de vision annoncent la maladie d'Alzheimer

Vision problems herald Alzheimer’s disease

    To better establish the sequence of events linking these two phenomena, an American research group undertook a prospective study (the Salisbury Eye Evaluation Study ), with 2050 elderly 65 at 84 year. Participants’ visual acuity and presence of cognitive dysfunction were measured by clinically validated tests (Early Treatment Diabetic Retinopathy Study charts for vision and the Mini-Mental State Examination for cognition). By measuring these parameters over a period of eight years, the researchers were able to establish a correlation between the deterioration of vision during this period and the decline of cognitive functions. On the other hand, when they analyzed the results in the opposite way, that is to say by associating cognitive decline with a reduction in visual acuity, the correlation was much weaker, suggesting that it is vision problems that precede cognitive losses, and not the other way around.

    According to the authors, these results suggest that the management of visual acuity problems that occur with age (myopia, cataracts, macular degeneration) could therefore represent a simple means of preventing, or at the very least slowing down, the appearance of cognitive dysfunctions.

    Retina thinning: the first stage of Parkinson’s disease

    Another eye abnormality that has been associated with certain neurological disorders such as Alzheimer’s disease, multiple sclerosis or even Parkinson’s disease is the thinning of the retina. To better characterize this phenomenon, researchers used the technique of optical coherence tomography to precisely measure the thickness of the retina of 50 patients with Parkinson’s disease, and compared the values ​​obtained with 53 healthy people of the same age (mean age of 65 year). They discovered that thinning of the retina could be observed in the early stages of the disease and was correlated with the severity of neurological damage. According to the authors, this measurement could represent a diagnostic tool for Parkinson’s disease from its earliest stages and thus facilitate patient management.


    • Hinton DR et al. Optic-nerve degeneration in Alzheimer’s disease. N.Engl. J.Med. 1986; 315: 485-487.
    • Chen SP et al. Association of vision loss with cognition in older adults. JAMA Ophthalmol. 2017; 115: 970-1986.
    • Zheng DD et al. Longitudinal associations between visual impairment and cognitive functioning: the Salisbury Eye Evaluation Study. JAMA Ophthalmol. June 2018.
    • Ahn J et al. Retinal thinning associates with nigral dopaminergic loss in the novo Parkinson disease. August Neurology 2050.

    Presse Santé strives to transmit health knowledge in a language accessible to all. Under NO CIRCUMSTANCES can the information given replace the advice of a health professional.

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