A recent study suggests that retinal scans could serve as an early diagnostic tool for mental illnesses, particularly schizophrenia, by detecting subtle changes in the retina linked to genetic risk factors for the disorder.
The retina, a key component of the central nervous system, directly connects to the brain, meaning that alterations in the brain could potentially manifest in the eyes. This insight prompted an international research team, led by the University of Zurich and the University Hospital of Psychiatry Zurich, to examine the connection between neural changes in the brain and retinal alterations in individuals genetically predisposed to schizophrenia.
Schizophrenia, a mental disorder characterized by disrupted neural processing, has been associated with decreased brain gray matter and thinning of the retinal tissue. However, the cause-and-effect relationship between these brain and retinal changes remains unclear. Factors such as antipsychotic medication, lifestyle choices, and coexisting conditions like diabetes may also contribute to retinal alterations.
Investigating Genetic Risk Factors in Healthy Individuals
To understand the relationship between genetic risk and neural changes, the researchers analyzed data from tens of thousands of healthy individuals. “We calculated polygenic risk scores for each individual to assess their genetic predisposition,” said Finn Rabe, the study’s first author and a postdoctoral researcher at the University of Zurich.
The study relied heavily on data from the UK Biobank, a vast biomedical database containing genetic and health information from over half a million people. According to Rabe, the scale of the UK Biobank’s data has significantly advanced biomedical research.
Thinner Retina Linked to Higher Genetic Risk
The findings reveal a clear connection between higher genetic susceptibility to schizophrenia and thinner retinas. However, the effects are subtle and can only be reliably detected in large-scale studies. One advantage of these retinal changes, compared to alterations in the brain, is that they are easier to detect through non-invasive and affordable retinal measurements. Optical coherence tomography (OCT), a type of eye ultrasound, enables retinal thickness to be measured within minutes.
“This method has the potential to be incorporated into clinical practice,” Rabe explains. “However, further large-scale longitudinal studies are needed to determine its effectiveness in predicting the onset of schizophrenia.”
Insights into New Treatment Possibilities
In addition to these findings, the study also uncovered genetic variants associated with inflammatory processes in the brain, which may contribute to structural changes in the retina. This lends further support to the inflammation hypothesis of schizophrenia, which suggests that inflammatory processes play a role in the disorder’s development or progression.
“If the inflammation hypothesis is confirmed, medications targeting these inflammatory processes could offer new avenues for treating schizophrenia in the future,” Rabe concluded.
With its potential to detect early signs of schizophrenia and other mental health disorders, retinal scanning could play a critical role in both prevention and the development of new treatments. However, more research is needed to fully assess its clinical applications.
