Specialist eye images taken during routine tests at high street opticians could help diagnose depression years before symptoms appear, according to a major study.
Researchers found that adults with wider blood vessels leading to the retina were up to 50 per cent more likely to develop depression over the following decade.
Ophthalmologists from the International Eye Centre at Shantou University in China conducted the research by examining eye imaging data from 40,000 healthy British adults. The participants were followed for an average of 11.3 years to track their long-term health outcomes.
During the tracking period, 1,402 participants were diagnosed with depression. The analysis revealed that having wider retinal veins was associated with a 25 per cent increased risk of the condition.
Retinal scans and inflammation
Scientists believe the link may stem from systemic bodily changes. One theory is that depression can drive chronic inflammation throughout the body, which may cause the veins of the retina to widen as a result.
The retina is a layer of light-sensitive tissue at the back of the eye that detects light and sends visual signals to the brain. High street opticians routinely capture specialist digital photographs of this area during standard eye tests.
Depression is a widespread mental health condition affecting mood and emotional well-being. Doctors currently lack an objective biological test for depression, relying instead on patient symptom reports and clinical evaluations.
Potential for early diagnosis
In the absence of an objective test, the researchers suggested that retina images could be a "promising, accessible candidate" to help diagnose the condition.
Writing in the Journal of Affective Disorders, they said: "Our study... provides strong evidence that vein widening precedes clinical depression onset."
The Journal of Affective Disorders is a peer-reviewed medical journal covering research on mood disorders. However, the scientists added that more research is needed before images of the retina can be used to diagnose the condition.
