Genetic Testing for Glaucoma: Enhancing Collaboration

SightScore Genetic Test kit and information pamphlets

Genetic testing is a new addition to the toolbox that’s being increasingly used by both optometrists and ophthalmologists to more effectively identify and manage patients at risk or suspected of glaucoma, as well as those with diagnosed disease.

This valuable tool is enabling clinicians to triage patients more accurately – weeding out those who don’t need to be seen as regularly as they otherwise may have been, and escalating care for those at higher risk of progression.

In doing so, genetic testing is saving money and resources at an individual and societal level. Perhaps most importantly, it is providing patients with reassurance that through a personalised treatment regimen, they have the best chance possible of retaining their sight for life.

SightScore is a simple, saliva-based test that analyses millions of genetic variants in a patient’s DNA to create a personalised polygenic risk score for primary open angle glaucoma. The brainchild of Jamie Craig, Professor of Ophthalmology at Flinders University, and his team, the tool was developed using genome wide association studies of over 400,000 individuals¹ and is accredited by National Authorities Testing Australia (NATA).

SightScore has been commercialised by Seonix Bio and was initially taken up by ophthalmologists, but is increasingly being used by optometrists to help determine management strategies and when to refer patients for specialist care, most often within a collaborative model.

Likened to “a crystal ball” the test provides clinicians with a picture (and description) of an individual patient’s predicted disease progression, mapping out when more frequent screenings will be required, and when treatments will need to be initiated and/or escalated.

Alex Hewitt, Professor of Ophthalmology at the University of Tasmania and the Centre for Eye Research Australia, who has been involved with the development of SightScore and recommends it to his own patients, explained that the test is particularly valuable for “potentially differentiating patients who you suspect of having glaucoma but don’t have any definitive signs of it”.

“It can help delineate the clinical pathway for that patient. If they’re in the high-risk group, you’d have a lower threshold for keeping a closer eye on the patient or potentially referring on for intervention.”

Additionally, SightScore can be used to identify and manage glaucoma patients at risk of more severe glaucoma who will need surgery, as well as family members of people with glaucoma who have inherited high genetic risk.

The report generated by SightScore has potential to change a clinician’s treatment plan for a specific patient. For instance, the report might indicate that a patient currently unaffected by glaucoma but at high genetic risk will develop the disease 15 years earlier than average, which would guide the clinician to begin monitoring much earlier than they otherwise would have.

For glaucoma suspects, SightScore delivers information about the risk of a patient needing to start treatment in the next three years. This information can be used to decide whether to see a patient every six months, every year, or every two years.

For glaucoma cases who are already on treatment, SightScore provides information about progression to more severe disease, including whether treatment escalation and/or surgery might be required.

in families with a known history of glaucoma, you’ll find siblings have quite different genetic risk profiles… and so the test can be useful for sorting out who needs to be prioritised within that family for screening

Supporting Clinical Decision Making

While genetic testing has an aura of complexity about it, Prof Hewitt said the SightScore test has been developed for ease of use and can, therefore, be used by “every optometrist in Australia screening patients for glaucoma”, regardless of their interest or experience with genetic testing.

For Kylie Sprumont, optometrist at Health Partners Optical in Adelaide, the decision to recommend the SightScore test to relevant patients was a no-brainer.

With a family history of the genetic disease cystic fibrosis (CF), Ms Sprumont has long held a personal interest in genetic testing. She, her siblings, and her children who are now at child-bearing age, have all been tested to determine their personal risk factors for CF.

“I just find genetic testing really interesting; knowing what traits come from who and which parts of the family,” she explained.

In her practice, where she sees a number of glaucoma patients, she said the data presented from the SightScore test has been particularly helpful.

“I’ve found it really helpful with patients we’ve been monitoring for years who perhaps have risk factors, like suspicious-looking optic nerves or high pressure, but have never shown up as glaucoma. Knowing if they’re at low, intermediate, high, or very high risk helps with deciding who to refer to a specialist, and who to monitor more closely.”

Ms Sprumont said the test results can also help determine appropriate monitoring intervals for more complex cases. “Some patients may have very large cupping or normal optic discs and quite high pressure, and they come back (with a SightScore result) as low risk… Quite often someone will do a visual field test and have a visual field defect, so we’ll get them to do it again days or weeks later and the visual field will be quite different.

“The test helps to know how frequently we might need to see them,” she said.

Enhancing Patient Communication

Jenny Spicer, principal optometrist at Donvale Optometry in Melbourne, was interested in genetic testing for glaucoma from the time she read about SightScore and soon after came across the SeonixBio booth at a tradeshow.

“I saw SightScore on display and went, ‘oh, it’s a real thing’.”

With “the most ghastly looking optic nerve discs and thin retinal nerve fibre layer”, Ms Spicer said she was keen to understand her own glaucoma risk profile and so decided to take the test herself.

Fortunately, the results showed that she has “a family history of really ugly looking discs and a thin nerve fibre layer… but not that much in the glaucoma stakes”.

For Ms Spicer, offering the SightScore test in practice has opened up important conversations with patients about family risk. She observed that the test is particularly valuable for patients with limited knowledge of their family history. “I especially offer it to anybody who says, ‘I don’t know what’s in the family – I’m adopted’ or ‘I’m the only one here’,” Ms Spicer explained.

In one notable case, testing a patient in their 20s with no signs of glaucoma showed a high 98th percentile risk, and led to examining 12 additional family members who were previously unaware of their potential risk.

“They came from across Melbourne because this was the first they’d heard of it (glaucoma),” said Ms Spicer. “They didn’t know that anybody else tested for it.”

Now regularly screening them all for the disease, she plans to suggest each of them undertakes the SightScore test over time.

And as Prof Hewitt explained, while clinical screening must always be the priority, genetic testing is invaluable for all family members of a person with glaucoma.

“Interestingly, in families with a known history of glaucoma, you’ll find siblings have quite different genetic risk profiles… and so the test can be useful for sorting out who needs to be prioritised within that family for screening,” he said.

For Ms Spicer, offering the SightScore test in practice has opened up important conversations with patients about family risk

Risk, Communication, and Patient Response

Contrary to potential concerns about causing patient anxiety, both of the optometrists who spoke to mivision have found that SightScore results typically reassure rather than worry patients.

In fact, Ms Sprumont has found that even high-risk results can be constructive.

“Those that come back with a high risk score that were quite worried about having glaucoma, feel reassured. If they come back with a high-risk score, I’ll usually refer them to an eye specialist and explain that while they might not need monitoring yet, if there are no signs of glaucoma, they’ve got their foot in the door with a good ophthalmologist.”

Prof Hewitt agreed. “This is a disease that’s not like Alzheimer’s or Huntington’s – we have therapies available that can prevent people from going blind. So, if the test shows you are in a high-risk category, it’s actually useful because we can intervene and prevent you from going blind.”

Despite the clear clinical benefits of genetic testing, there are concerns surrounding data privacy and the ability for people diagnosed with a genetic risk of disease to obtain personal insurances.

On the issue of data privacy, Prof Hewitt said that with the SightScore test conducted through an accredited laboratory with robust privacy protocols, data protection is assured.

Regarding insurance implications, he said recent developments have removed a potential barrier to testing. “The Australian government has recently stated that they will legislate to say that people cannot be discriminated against based on their genetic background,” Prof Hewitt explained.

Indeed, the Hon Stephen Jones MP, Assistant Treasurer and Minister for Financial Services said in a statement issued in September last year, that “No Australian should be discouraged from undertaking testing out of fear it may impact their ability to get life insurance”.²

The statement described genetic testing as “a life-saving step” and said this “valuable technology supports medical practitioners to prevent, diagnose, treat, and monitor a range of heritable conditions…”.

“The Albanese Government will end the ability to discriminate based on adverse predictive genetic test results by banning their use in life insurance underwriting.

“This decision places Australia as a world leader in removing barriers to genetic testing by stopping the use of adverse predictive test results in life insurance.”

I think there’ll probably come a time when this test is implemented with a barrage of other genetic risk profile tests.

Practice Benefits

For optometry practices, SightScore can strengthen patient relationships and expand patient bases through family referrals – as demonstrated by Ms Spicer’s experience of gaining 12 new patients from a single SightScore test.

And, although some patients initially hesitate at the cost of AU$349, Ms Sprumont argued that it can represent good monetary value and can also delay the need for a visit to the ophthalmologist.

“We don’t bulk bill optical coherence tomography (OCT) scans, so for people who are coming back every six months to do an OCT that costs them $51 each time. If they come back with a low SightScore result, they might not need to have OCTs as frequently, which might save them money in the long run.”

In the future, Prof Hewitt believes the provision of genetic testing will become routine for optometrists, ophthalmologists, and other health professionals.

“I think there’ll probably come a time when this test is implemented with a barrage of other genetic risk profile tests. Just like when you turn 40, you have all your range of cholesterol tests, you’ll have your background genetic risk for glaucoma, age-related macular degeneration, breast cancer, prostate cancer, all done. Then we’ll end up getting precision medicine and a prioritisation of healthcare services based on a person’s genetic risk profile.”

Implementation Strategies

For optometrists considering implementing SightScore, both Ms Spicer and Ms Sprumont recommend introducing it during routine glaucoma risk assessments.

Ms Sprumont provides information to all patients with a family history of glaucoma or those being monitored as glaucoma suspects, giving them time to consider the test and discuss it with family members.

“I just ask them if they’ve heard about the SightScore test and I explain what it does, that it’s really simple and I just say that it’s another tool in the toolbox that will help us to know how closely to monitor them and what their risk factors are for it,” she said.

“About a quarter will book (for the test) then and there but for most, I give them a brochure… and they’ll often ring up a week, or a month, or six months later and book in. I explain that glaucoma is genetic, that this is a genetic test, and get them to talk to their family about it – and some family members have decided to come back and do it as well.”

The test reports include both graphical and text-based explanations, allowing practitioners to tailor their communication to individual patient preferences. “Some people are better at reading graphs and some people are better at reading text,” noted Ms Sprumont. “The fact that it comes with both is really helpful.”

Optimising Outcomes with Scarce Resources

At a time when ophthalmologists are a finite resource, and yet the amount of eye disease continues to grow in line with an ageing population, optometrists are perfectly placed to embrace SightScore and other genetic tests for eye disease as they become available.

By providing objective risk assessment data, evidence-based genetic testing can support clinical decision making, enhance patient communication, and facilitate collaborative care, all while ensuring the most effective use of scarce resources.