NZ Optics article by Lesley Springall
WITH HER MOTHER having severe glaucoma in both eyes, Megan Brown has become the first person to be genetically tested for primary open-angle glaucoma (POAG) in New Zealand.
Auckland-based glaucoma specialist and chair of Glaucoma New Zealand (GNZ) Professor Helen Danesh-Meyer, who conducted the test on Brown, said the newly launched SightScore™ polygenic risk test could make a huge difference to patients and their eyecare practitioners. It provides another piece in the puzzle when it comes to assessing patients for glaucoma, she said. “We all have this large basket of ‘glaucoma suspects’ we are taking care of. This information has the potential to provide more clarity on where they are in the spectrum of developing glaucoma. If a person has high intraocular pressures (IOPs) and the test result comes back that they have a high genetic risk for developing glaucoma, we can then discuss whether the benefits of treatment now outweigh the risks of waiting.” Conversely, those patients found to be low risk may not need to be monitored so often, she said.
SightScore™ was unveiled in Auckland at an event hosted by GNZ and clinical research organisation the Vision Research Foundation, prior to the annual GNZ Symposium. Addressing a mixed audience of optometrists, vision researchers, ophthalmologists and key GNZ supporters, symposium keynote and SightScore™ co-developer Professor Jamie Craig said New Zealand is only the second country in the world, after Australia, to have access to the new test.
It was developed using genome-wide association studies involving more than 400,000 individuals and has been improved and validated in a range of clinical cohorts, he said.
“We now have a very large number of common genetic variants, which we can combine into a single risk score to determine the patient’s likelihood of developing glaucoma.”
The test involves a simple saliva swab, which is processed within four weeks by Seonix Bio in Adelaide, a company co-founded by Prof Craig to produce the new polygenic risk score (PRS) test.
In combination with a patient’s medical history, clinical risk factors and clinical eye exam, the PRS can assist practitioners with different patient-management decisions, said Prof Craig, including how often a patient should be monitored for glaucoma and whether that’s by an optometrist or an ophthalmologist; when they should be prioritised for referral; what management strategy should be employed, including treatment priorities; and whether their blood relatives should be checked for glaucoma, too.
SightScore™ may also be useful for individuals to better understand their own risk so they can be more proactive with their healthcare, he said. “Our studies have shown that a high polygenic risk is associated with earlier initiation and escalation of treatment in early POAG. So for me this is changing the way I think about patients at all sorts of levels.”
The SightScore™ test only looks at a patient’s genetic risk of developing adult-onset POAG; it does not test for angle-closure glaucoma or juvenile glaucoma, he added.
Supported by the Australian government and led by Flinders University and the Queensland Berghofer Medical Research Institute, the SightScore™ research team is in the process of conducting further trials to see if early intervention with high-risk glaucoma suspects prevents glaucoma onset, said Prof Craig, stressing that PRS is a decision-support tool, not a diagnostic test. “For example, we don’t really want to see low-risk suspects as it takes up slots for other patients who really need treatment.”
The true impact of the SightScore™ test on patient management will depend on the results of these clinical trials, said Prof Danesh-Meyer. “But it is exciting that genetics looks like it will have a place in our clinical practice.”