What would you think if words started disappearing suddenly from the page while you are reading? If you started noticing dark spots on the screen while watching television. Or suddenly had difficulty recognizing faces?

While it might seem like your mind is playing tricks on you, in the case of age-related macular degeneration (AMD), these disorienting experiences are caused by structural damage to the eyes.

Clinicians and researchers have struggled to find a predictive measure that identifies patients at risk for developing the advanced stages of the disease.

Researchers at Massachusetts General Hospital and Massachusetts Eye and Ear may have identified a solution. The team has successfully tested a new method for identifying patients with AMD by looking at specific markers in their blood.

The blood-based test has the potential to improve early diagnoses for AMD patients and inform new strategies to delay or stop the onset of the disease.

What is Age-Related Macular Degeneration?

Known as the “Alzheimer’s of the eye,” AMD affects nearly five million people across the world, and is the leading cause of blindness in people over 50 in developed nations.

The disease is caused by a buildup of yellowish lipid proteins underneath the retina, the light sensitive portion of the eye. Over time, these proteins damage the structure of the retina, which leads to disorienting visual symptoms like missing words on a page, the sudden appearance of spots and the inability to identify faces.

By the time patients start to experience the visual degradation that accompanies AMD, however, the damage is already done.

Finding a Method for Diagnosis

To test out their new method for diagnosing AMD, scientists took blood samples from 90 participants with varying degrees of AMD, including early, intermediate and late-stage cases. These samples were then compared to 30 individuals who do not have AMD.

Researchers used a new technique known as “metabolomics,” — the study of tiny particles called metabolites in the body that reflect our genes and environment.

Their analysis revealed 87 metabolites that were significantly different between subjects with AMD and those without. The team also noted varying characteristics between the blood profiles of each stage of disease.

Out of the 87 molecules identified, the majority were found to be lipids, which have long been a point of interest in AMD research.

“Because the signs and symptoms of early stage AMD are very subtle, with visual symptoms only becoming apparent at more advanced stages of the disease, identification of [lipid] biomarkers in human blood plasma may allow us to better understand the early to intermediate stages of AMD so we may intervene sooner, and ultimately provide better care,” said co-senior author Joan W. Miller, M.D., Chief of Ophthalmology at Massachusetts General Hospital and Mass Eye and Ear.

Preventative Measures

More research needs to be done before the blood tests are available in the clinic. For now, the best way to monitor patients for signs of AMD is by conducting regular eye tests after the age of 45.

Given that risk factors for AMD include being overweight, having high blood pressure and smoking or drinking alcohol to excess, it may be possible to reduce your risk by making healthy lifestyle choices, including:

• Maintaining a healthy weight
• Eating lots of green leafy vegetables and fish
• Quitting smoking
• Managing your blood pressure

About the Mass General Research Institute
Research at Massachusetts General Hospital is interwoven through more than 30 different departments, centers and institutes. Our research includes fundamental, lab-based science; clinical trials to test new drugs, devices and diagnostic tools; and community and population-based research to improve health outcomes across populations and eliminate disparities in care.
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