Since the human eye and the brain have many vascular and neurological similarities, it has been shown that our eyes can provide a clear window into the pathology of the brain. Our eyes’ distinctive qualities make them an effective biomarker for conditions like Alzheimer’s disease (AD) and other brain disorders.
Currently, AD can only be diagnosed if a patient begins to exhibit early cognitive decline. Cognitive or mental state tests are used to make a formal diagnosis, but the diagnosis can only be verified by looking at the brain after death.
A-42, T-tau, and p-tau, which are found in the CSF fluid, as well as fluorodeoxyglucose and Pittsburg Compound B, which are found in the brain, are well-known biomarkers for AD that are now in use. Although the broad use of these biomarkers remains a barrier, they are essential for AD monitoring.
AD visual biomarkers
Patients with Alzheimer’s disease frequently have visual symptoms, which inspired researchers to search for new ocular biomarkers for AD. According to studies, specific visual symptoms may be a sign of dementia as well as the beginning of senile plaques in the brain’s visual regions.
Structural retinal biomarkers were identified to have the potential to aid in the early identification of AD as more information about the progression of events and the neurodegenerative alterations in AD is learned. Blood-brain barrier disruption, poor A clearance, vasoconstriction, decreased blood vessel density, and blood flow is among the most often mentioned vascular problems in AD.
The most promising AD biomarker may be directly observing the symptoms of AD in the retina due to its specificity for AD. To confirm that A plaques are present in retinal tissues and that these retinal deposits are indicative of cerebral deposits, more research is required. A visual version of AD known as VVAD has also been observed to affect comparatively younger persons. Patients with VVAD first experience visual symptoms in their 50s or 60s and subsequently experience the cognitive impairment typical of AD patients.
Pupillary responses, including pupil size and pupillary sensitivity to light, are non-retinal indicators for AD. Eye movements are important because AD patients struggle to read because of poor eye motions that are thought to be related to memory. It has been observed that AD patients have slower eye movements and increased delay during voluntary eye movements. Additionally, they may be unable to focus on or follow a moving target.
The eye is relatively accessible, retinal imaging is a straightforward technique, and these visual changes are important and early signs of brain pathology, all of which make ocular biomarkers quite alluring.
the Duke Eye Center for Research
According to a study by Duke Eye Center experts, Alzheimer’s and other brain disorders may soon be identified through a simple eye checkup. More than 200 people’s retinas were examined in the study to look for any potential distinctions between those with and without Alzheimer’s disease.
The findings demonstrated that individuals with a healthy brain have a substantial network of blood vessels visible during an eye exam in their retina. In people with a sick brain or Alzheimer’s disease, this tiny web of blood vessels was far less noticeable.
Optical coherence tomography angiography (OCTA), a non-invasive technique, was employed by the researchers to capture high-resolution pictures of the retina’s tiny blood veins. They came to the conclusion that since the retina can be thought of as an extension of the brain, variations in the density of the retinal blood vessels may be a sign of the health of the cerebral blood vessels and so aid in the early diagnosis of brain pathology.
Ocular AD biomarkers’ future
Although they are still in their infancy, ocular biomarkers for AD show great potential for the identification of A-related retinal alterations, which are highly specific for AD pathogenesis. It is believed that the identification of these ocular indicators has the potential to significantly increase our understanding of AD.
The identification of new diagnostic and therapeutic approaches that can enhance the quality of life for people with brain diseases is anticipated to be made possible by the development of ocular biomarkers. Future studies should concentrate on ways to make this field even more advanced.