John Nguyen examines a young patient
John Nguyen, co-owner of Zoom Optics and an optometrist of 19 years’ experience, had an unusual introduction to the practice of orthokeratology (OK), deciding that he wanted to be his own first patient. As Vivienne Pearson writes, Mr Nguyen “wanted to go through the whole experience” so he’d know “exactly what the patient was going through”.
Orthokeratology is the procedure of deliberately reshaping the anterior cornea by prescribing specially designed rigid lenses to be worn overnight. Not only can these highly oxygen-permeable lenses allow patients to spend their days free from glasses or contact lenses by temporarily reversing mild to moderate myopia, they are now an option for slowing the progression of myopia in children.
OK – the process of using reverse geometry lens design – is also known as orthoK. The overall idea was first presented as ‘ortho-focus’ by George Jessen in 1962 at the International Society of Contact Lens Specialists.1
However, it took advances in lens technology across more recent decades, including sophisticated topography measurements and computerised numerical controlled lathes, for OK to be brought into the realm of mainstream practice.
Mr Nguyen, who only developed mild myopia as a new graduate optometrist, found OK a surprising experience. “After the very first night, my vision was so sharp, it was crystal clear,” he recalled. “I’d never seen the world in that high definition, even before I started wearing glasses. That’s what I’ll always remember.”
Such immediate improvement is not always achieved. Mr Nguyen, who has been prescribing OK lenses since 2011, tells prospective patients that ideal refractive control might take up to a week of wear or, for older patients and those with a higher prescription, more like a couple of weeks.
I get that it can be intimidating to delve into OK as it’s quite technical.
The Shift to Children
Associate Professor Pauline Kang, of the School of Optometry and Vision Science at UNSW, has been researching OK since completing her PhD as part of Australia’s first clinical trial led by Professor Helen Swarbrick, and was part of the BCLA CLEAR (British Contact Lens Association Continued Learning Evidence-based Academic Reports) overview of OK.2 She said research into OK had shifted from adults to myopia control in children: “In the early 2000s, mainly in Asia, anecdotal feedback from practitioners triggered the first trials of OK for myopia control.”
Assoc Prof Kang noted that the science on OK for myopia control is now accepted as settled, as summarised in the Cochrane Review: “Based on short-term studies, orthokeratology is the most effective of the optical treatments in slowing elongation of the eyeball.”3
As a consequence, her research moved onto investigating finer specifics of lens design for optimising optical focus manipulation, as well as combination optical, pharmacological, and environmental therapies,4 such as combining OK lenses with atropine.
An early recipient of the myopia control use of OK lenses was new graduate optometrist, Sophie Lam, also from Zoom Optics. “I’ve been wearing OK lenses since I was eight after being diagnosed as a low myope during a routine check,” said Ms Lam, who is now aged 23. “However, my prescription then doubled in the span of a year, prompting concern.”
OK solved two problems for Ms Lam. Her myopia has been stable in the 15 years since she started wearing the lenses. And she was able to ditch the glasses her grandparents had chosen for her. “They didn’t align with my fashion style, and I was so embarrassed wearing them at school,” she mused.
Ms Lam, who graduated with a Master of Clinical Optometry from University of New South Wales in 2023, said it’s not always easy for newcomers to OK to get the experience needed to practice solo.
“I get that it can be intimidating to delve into OK as it’s quite technical.
“I’m most confident with follow-up consultations with existing wearers and, when it comes to the more complex initial stages, I reach out to John (Nguyen). That’s why it’s crucial to have a supportive mentor who has an established OK patient base.”
Mr Nguyen said five of the seven Zoom Optics practices are set up for OK, adding that his 13 years of experience is valuable for colleagues new to the treatment, as “an existing patient base and learning from someone on the job is essential”.
Patient Suitability
Mr Nguyen said one of most important clinical aspects of prescribing OK is patient screening. Though he mentions OK to every parent of a myopic child, he knows not everyone is suitable. “For children, it’s a family decision,” he said. “There are cost and compliance issues, so everyone has to be on the same page and there are certainly situations where I’ve advised against it.”
Assoc Prof Kang, whose work includes running the University of New South Wales Myopia Clinic, agreed. “If we feel the child is not mature enough to handle lenses, or if they’re not motivated enough, we wouldn’t give them the option, but we also know it might only be a few years later that OK is appropriate.”
She noted that some practitioners are wary about OK due to the potential risks of infection but encouraged confidence. “If the practitioner has the right expertise to fit lenses appropriately and educate the patient properly, there should be minimal risk of adverse events,” she said. Mr Nguyen said he focusses firmly on education and close follow-up until it’s clear the patient is managing well.
Training Gaps
There is no entry-level requirement for starting to practise OK. Undergraduate students do not have comprehensive training in OK during studies and are not guaranteed clinical exposure during placements either. Acknowledging the gap in training, Assoc Prof Kang said, “We try to expose students to all the different types of lenses, but the curriculum is already so packed, we don’t have capacity to teach all students how to fit OK lenses.”
Ms Lam said because of her interest in OK, as a student, she would “volunteer to watch some of the fittings but not every student would be exposed to the process”.
Helping to fill that gap in knowledge is the Orthokeratology Society of Oceania (OSO). President, Dr Gavin Boneham, said boot camps would be offered around the Society’s October 2025 conference, with options for practitioners at all levels of experience. The Society also offers OK education as part of an International Academy Certification in Myopia Management (IACMM) and, for those seeking high levels of expertise, mentoring and assessment for Fellowship in the International Academy of Orthokeratology and Myopia Control (FIAOMC).5
Lens Manufacturers
Another useful resource for eye health professionals is lens manufacturers. Mark Masel, Technical and Support Manager at Gelflex, one of only two Australian contact lens manufacturers, said there are options for all levels and preferences. “We’ve got the knowledge to help with every step of the process,” he said. “If you send us the topography and spectacle Rx, our team can design Gelflex Ortho-k and Euclid lenses. Or, for people who prefer the fitting set approach, we are the exclusive distributor of Paragon CRT lenses in Australia and New Zealand.”
Mr Masel continued, “For optometrists who prefer to have full control over contact lens design, Gelflex manufactures the Wave lenses, which allows the optometrist to customise lenses based on their own fitting philosophy.
“So, as you can see, we have a toolbox that caters to all types of practitioners and their needs.”
A Bit of Magic
Dr Boneham said he remains excited about OK, even after 30 years of experience. “You’ve got to put the time in to learn and have the equipment but, if you want to love coming to work, OK is one of the things you need to be doing,” he said. “OK adds a little bit of magic to your professional life.”
For Mr Nguyen, OK has resulted in some of his most meaningful clinical experiences. “I see the positive impact of the self-esteem that freedom from glasses and contact lenses brings,” he said. “I’ve had patients say to me: ‘this is the best thing that’s ever happened to me’ and to give someone that life-changing moment is a beautiful thing.”
Vivienne Pearson is a freelance writer. She was commissioned by Zoom Optics to write this article for mivision.
References
- Norman CW. The history of orthokeratology: how far have we come? The Ortho-K Knowledge Bank. Available at: orthokknowledgebank.reviewofmm.com/the-history-of-orthokeratology-how-far-have-we-come/ [accessed Nov 2024].
- Vincent SJ, Cho P, Jones L, et al. BCLA CLEAR – Orthokeratology. Contact Lens and Anterior Eye 2021;44(2):240-269. doi: 10.1016/j.clae.2021.02.003.
- Walline JJ, Lindsley KB, Twelker JD, et al. Interventions to slow progression of myopia in children. Cochrane Database of Systematic Reviews 2020 Jan 13;1(1):CD004916. doi: 10.1002/14651858.CD004916.pub42020.
- Samrat S, Khuu S, Kang P. A systematic review and meta-analysis of the efficacy of different optical interventions on the control of myopia in children. Acta Ophthalmol. 2024 May;102(3):e229-e244. doi: 10.1111/aos.15746.2024; e229–e244.
- Orthokeratology Society of Oceania. Further information available at: oso.net.au [accessed Nov 2024].
