A study of 33,068 patients has shown a link between the thinning of the retinal nerve and poor cognition – an important and clear warning of early stage Alzheimer’s disease. Researchers at Moorfields Eye Hospital and the UCL Institute of Ophthalmology worked together on this sizeable study, which indicates the potential for routine eye checks to be used as a biomarker for Alzheimer’s in the future.
The UK Biobank study was used to test the hypothesis, giving the researchers access to a large community-based population sample. The participants were given a series of tests on memory, reaction time and cognitive reasoning as well as macular spectral-domain OCT and a physical examination.
Those who scored abnormally on one cognition test had a thinner retinal nerve fibre layer (RNFL) in comparison to those who scored normally. In one of the tests, the prospective memory test, RNFL thickness was 53.3 µm in those who recalled correctly the first time, compared with 51.9 µm with those who did not recall.
“these exciting findings show the value of large-scale studies for identifying new biomarkers…which could lead to the discovery of new mechanisms of neurodegeneration”.
Mr Praveen Patel, Consultant Ophthalmologist, Moorfields Eye Hospital
The thinning of the macular RNFL was seen in combination with poorer pairs machine, poor numerical and verbal reasoning as well as slower reaction time, with the effects being additive for each failed cognitive test.
This large study shows huge potential for the eye, and visual screening, as a non-invasive method of measuring neurodegeneration, with the macular being a biomarker for conditions like Alzheimer’s and dementia.
A previous 2013 study in France, which we covered on our blog, backs up the research by the Moorfield and UCL team so it is a topic that will definitely develop in the coming years and months. Measuring neurological function via the macular and macular pigment means that Alzheimer’s could be detected much earlier and more easily, meaning treatments to slow the progression of the disease can be more effective for a longer period of time.