If vision begins to give attention to the brain: it could be one of the first signs of dementia and – if visual sensory stimuli are reduced – its progression increases. This is suggested by some studies from which a link emerges between some of the most common eye diseases – such as age-related macular degeneration, cataracts, eye diseases related to diabetes and glaucoma – and cognitive deterioration. The incidence of these ophthalmic conditions increases with age, as does the incidence of systemic conditions such as diabetes, hypertension, heart disease, depression, and stroke, which are accepted risk factors for dementia. This was revealed by a work published in the British Journal of Ophthalmology and conducted by Xianwen Shang, of the Guangdong Academy of Medical Sciences, Guangzhou in China.
With diabetic retinopathy 61% risk
The experts considered a sample of 12,364 adults aged 55-73 enrolled in the British study Biobank. Participants were monitored between 2006 and 2010, up to 2021. During the whole period, 2,304 cases of dementia were recorded. It was found that compared to people without visual disorders at the start of the study, the risk of getting dementia is 26% higher for those suffering from macular degeneration, 11% higher for those who have cataracts, 61% higher for those with cataracts. suffering from diabetic retinopathy. Glaucoma, on the other hand, was not associated with a
increased risk of Alzheimer’s disease, but at a greater risk of vascular dementia.
The other pathologies
At the start of the study, participants were also asked if they had ever had heart attack, angina, stroke, hypertension, or diabetes, and were evaluated to see if they had depression. At the end of the study, the experts were able to observe that the risk of dementia increases further if people also suffer from diseases such as diabetes, cardiovascular problems and depression. Suffering from one of these conditions and even an ophthalmic problem further increased the risk of dementia which was even greater when diabetes-related eye disease occurred along with a systemic condition. Furthermore, the risk of dementia was higher among individuals with multiple ophthalmic conditions.
The limits of the study
As this is an observational study, a cause / effect relationship cannot be established, and the authors also highlight several potential limitations, mainly related to data acquisition. The ophthalmic conditions, in fact, were defined on the basis of self-reported data and the registers of hospitalized patients. This means that there may be an underestimate, that medical records and death records may not have identified all cases of dementia, and that some cases of cognitive decline documented during follow-up may have occurred before eye diseases. “The fact remains – the researchers conclude – that age-related macular degeneration, cataracts and eye diseases related to diabetes, but not glaucoma, are associated with an increased risk of dementia”.