Australian Researchers Develop a Superior Genetic Blood or Saliva Test for Detecting Glaucoma in High-risk Individuals

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Should the test prove clinically viable, it could lead to new biomarkers for eye disease diagnostics and a new assay for clinical laboratories

Scientists at Flinders University in Australia have developed a genetic blood or saliva test that, they say, is 15 times more effective at identifying individuals at high risk of glaucoma than current medical laboratory tests.

If so, this discovery could lead to new biomarkers for diagnostic blood tests that help medical professionals identify and treat various diseases of the eye. Their test also can be performed on saliva samples. The researchers plan to launch a company later in 2022 to generate an accredited test that can be used in clinical trials.

“Early diagnosis of glaucoma can lead to vision-saving treatment, and genetic information can potentially give us an edge in making early diagnoses, and better treatment decisions,” said lead researcher Owen Siggs, PhD, Associate Professor, College of Medicine and Public Health at Flinders University, in a university press release.

Flinders University researchers have been collaborating with scientists at the QIMR Berghofer Medical Research Institute and other research institutes worldwide for some time to identify genetic risk factors for glaucoma, the press release noted.

The researchers published their findings in the peer-reviewed journal JAMA Ophthalmology, titled, “Association of Monogenic and Polygenic Risk with the Prevalence of Open-Angle Glaucoma.”

“In the cross-sectional study of monogenic and polygenic variants related to the disease, the new genetic test was evaluated in 2,507 glaucoma patients in Australia and 411,337 people with or without glaucoma in the UK. The test, conducted using a blood or saliva sample, could potentially detect individuals at increased risk before irreversible vision loss happens,” Medical Device Network reported.

“Genetic testing is not currently a routine part of glaucoma diagnosis and care, but this test has the potential to change that,” said Jamie Craig, PhD, (above), Distinguished Professor, College of Medicine and Health at Flinders University in Australia and senior author of the study, in a press release. “We’re now in a strong position to start testing this in clinical trials,” he added. This is yet another example of how new research is identifying a novel biomarker that could be incorporated into a clinical laboratory test.

Who Is at Risk for Glaucoma?

Glaucoma is a group of eye diseases that are typically caused by a buildup of pressure within the eye. The eyeball contains and produces a fluid called aqueous humour which provides nutrition to the eye and keeps the eye in a proper pressurised state. Any excess of this fluid should be automatically released via a drainage canal called the trabecular meshwork.

But that’s not always the case. When the fluid cannot drain properly, intraocular pressure is created. Most forms of glaucoma are characterised by this pressure, which can damage the optic nerve and eventually cause vision loss and even blindness. Treatments for the disease include medications, laser treatments, and surgery.

Anyone can develop glaucoma, but according to the Mayo Clinic, individuals at higher risk of the disease include:

• Individuals over the age of 60.
• Those with a family history of glaucoma.
• People of African, Asian, or Hispanic descent.
• Patients with certain medical conditions, such as diabetes, heart disease, high blood pressure, and sickle cell anemia.
• Those with corneas that are thin in the centre.
• Individuals who have had a past eye injury or certain types of eye surgery.
• People who have taken corticosteroid medications, especially eyedrops, for an extended period of time.

Glaucoma is the second leading cause of blindness worldwide, particularly among the elderly. When diagnosed early, the condition is manageable, but even with treatment, about 15% of glaucoma patients become blind in at least one eye within 20 years.

According to the federal Centers for Disease Control and Prevention (CDC), approximately three million Americans are living with glaucoma. The disease often has no early symptoms, which is why it is estimated that about 50% of individuals who have glaucoma do not realise they have the illness.

Thus, a clinically-viable genetic test that is 15 times more likely to identify people at risk for developing glaucoma in its early stages would be a boon for ophthalmology practices worldwide and could save thousands from going blind.

More research and clinical trials are needed before the Flinders University genetic test for glaucoma becomes available. But the discovery alone demonstrates the importance of continuing research into identifying novel biomarkers that could be incorporated into useful clinical laboratory diagnostic tests.