Feature, Report

Detect and treat: contact lens technologies of the future

contact lens technologies

Insight explores how contact lens innovations are venturing beyond conventional boundaries as a means of vision correction, to another realm where new technological features are being developed for diagnostic and drug-delivery purposes.

Marking the 50th anniversary of the soft contact lens this year, the vice president of R&D for vision care at Bausch + Lomb remarked on how this single invention triggered a whole series of other innovations that are ubiquitous in the optical sector today but were completely unknown at the time.

As contact lenses evolve over the next five decades, it is worth considering what other advances are on the horizon.

In April this year, a stand-out academic review provided arguably one of the clearest answers to this question by demonstrating the incredible diversity of new technologies that are set to shape the future contact lens segment.

Published in Contact Lens and Anterior Eye, the official journal of the British Contact Lens Association (BCLA), two well-known names in Australia were among the article’s 14 researchers: Professor Mark Willcox and Canadian-born Dr Alex Hui. The study was the latest in BCLA’s Contact Lens Evidence-based Academic Reports (CLEAR).

In ‘CLEAR – Contact lens technologies of the future’, Willcox, Hui et al note that rapid growth in novel biomaterials and the development of powered contact lenses through advancements in nanotechnology “will enable the commercialisation of lenses that can both detect and treat ocular and, in some cases, systemic disease”.

The review also takes into consideration new concepts like biosensing capabilities and antibacterial surfaces to produce safer contact lens cases and materials, reducing the likelihood of sight-threatening microbial keratitis and infiltrative responses.

Willcox and Hui talk with Insight about the CLEAR review, while two optometrists with a special interest in contact lenses discuss advancements from their clinical perspective.

Unlimited potential 

Since contact lenses were invented in 1887, innovations have included advances in optical design, material, care systems, wear modality, lens size, lens shape and applications, according to CLEAR.

In fact, this year marks the 50th anniversary of the soft contact lens, with Bausch + Lomb’s SofLens introduced in 1971. The company says it became the first mass-produced soft contact lens in the US market shortly after the Food and Drug Administration (FDA) granted approval of the novel device. This breakthrough and the many follow-on innovations have led to a US$15 billion (AU$19 b) per annum contact lens market today, according to Vision Monday.

More recently, in November 2019 the FDA’s approval for the use of MiSight 1 day (CooperVision) for myopia control in children was an important milestone – and signalled another breakthrough in contact lens design and performance.

A medical microbiologist who has worked for many years in infections of medical devices, Willcox is research director at UNSW School of Optometry and Vision Science. He has watched the evolution of contact lenses from the advent of cheap, disposable soft lenses in the 1980s to silicone hydrogel lenses in the late 90s, to a soft toric lens in 2002, to myopia control lenses today.

unsw contact lens.
Prof Mark Willcox.

“In the last few years, we’ve witnessed the re-discovery of orthokeratology rigid lenses. Although they’ve been around for a while, they fell out of favour, but have had a comeback, with better materials and better design,” Willcox says.

In recent years the success of myopia control contact lenses, and their commercial availability, have virtually elevated them to best practice, he says, but there could be even further advances in this field.

But in the CLEAR report, the researchers explain many of these approaches are related to innovations that appear in patent articles and not in the scientific literature and, therefore, may be in planning or pre- clinical development stages.

For example, a PhD student who Willcox is supervising at UNSW is investigating contact lenses as a drug delivery device, by combining a myopia control lens to deliver atropine, which is currently administered as a nightly eye drop.

“Delivering atropine through a contact lens could potentially produce a more sustained release over a longer period,” Willcox says.

Other forms of therapeutic contact lenses have taken a significant step forward this year.

In March, Johnson & Johnson (J&J) Vision’s world-first drug-releasing contact lens for vision correction and allergic eye itch was approved by the Japanese Government. It was the first health authority to clear the novel device, with Canada following in April.

The approved combination contact lens – Acuvue Theravision with Ketotifen –contains an H1 histamine receptor antagonist to prevent itch associated with eye allergies, including conjunctivitis and hay fever.

Willcox says J&J’s lens – the first commercial drug delivery contact lens to reach the market – represents an exciting prospect but it has taken years to come to fruition.

“This development has arrived after 10 years of research and design, and numerous clinical trials. Generally speaking, there has been regulatory hesitancy around delivering drugs in contact lenses – a novel idea that has fallen in and out of favour,” Willcox says.

Although the industry has metaphorically turned a corner with approval granted in Japan and now Canada, TGA approval in Australia for this lens may be a different proposition, Willcox cautions, because of tighter regulatory controls.

He says J&J’s drug-releasing antihistamine contact lens hints at unlimited potential.

“We could, in theory, use contact lenses to deliver drugs, such as antibiotics, for ocular conditions from blepharitis to keratoconus. We could use contact lenses to deliver glaucoma drugs, which are currently administered as eye drops. It can be difficult for elderly patients to put eye drops in – not only manually using an eye drop device but also remembering to do it. Contact lenses could maybe even deliver cyclosporin for dry eye,” Willcox ventures.

While laboratories are actively designing contact lenses with capabilities beyond mere vision correction, the performance of contact lens packaging and storage is also an area of focus.

“Manufacturers are trying to design packaging that eliminates wearers touching the lenses to reduce the risk of bacterial transmission. Menicon’s flat pack technology is leading the way, designed in such a way that wearers don’t handle the lens,” Willcox says.

As a one-time-use medical device, daily disposable contact lenses, by design, don’t require disinfection, but monthly contact lenses do, and here a new challenge is being addressed.

“When disinfecting lenses overnight, we get bugs colonising in contact lens cases. If you replace contact lens cases regularly, monthly, you are less likely to get infections. Is there a way contact lens cases can discolour to indicate there are too many bugs present, or is there a way contact lens cases can disintegrate if there are too many bugs to be safe?,” Willcox says, noting these are some of the ideas being explored in research labs.

In his own lab at UNSW, he is investigating an antimicrobial contact lens’ inherent ability to kill bugs. A Phase 3 trial – a large population study in India – completed two-to-three years ago showed a 50% reduction in inflammation.

Now, Willcox is working on a next-generation antimicrobial contact lens, modifying peptides to be resistant to bacteria for a duration of two weeks of contact lens wear.

“We’ve finished designing the contact lens and have now moved into animal studies as part of pre-clinical evaluation. In about a year’s time, we hope to receive Proof of Principle and move into Phase 1 human trials.”

Incorporating microelectronics into contact lenses to detect disease is another surging field of research and design. Here, Willcox says, the task of miniaturising power sources is “challenging, but not insurmountable”.

“It will take a few years to get right,” he says.

One product leading this field is the Sensimed Triggerfish contact lens, a commercially available device with CE marking and FDA approval that permits extended monitoring of IOP. According to the CLEAR review, this flexible silicone-based contact lens measures minute dimensional changes in corneal shape, which correspond to changes in ocular biomechanical properties and volume, as well as IOP.

“Triggerfish is likely to be the first in a generation of commercially available contact lens-based devices to monitor ocular biomarkers of disease. However, there are a number of limitations with the current device, principally driven by the bulky microprocessor and strain gauge assembly,” the CLEAR authors state.

A second-generation Triggerfish lens is currently in the pipeline.

Uptake and release 

Willcox’s colleague and fellow author of ‘Contact lens technologies of the future’, Dr Alex Hui completed his PhD at the University of Waterloo and the Centre for Contact Lens Research, where he investigated drug- releasing contact lenses.

Now a Senior Lecturer at the School of Optometry and Vision Science at UNSW, his work in this field is ongoing.

Dr Alex Hui unsw contact lens
Dr Alex Hui.

“I’m interested in the ability of contact lenses to tailor therapeutic drug- release to treat and prevent infection, such as using contact lenses to release antibiotics after laser surgery,” Hui says.

“The patient is already wearing a bandage contact lens after some procedures, so that lens could potentially also release antibiotics to help them recover, instead of being required to put in eye drops. But there are marketing issues around delivering drugs this way. We need to overcome this hurdle.”

The CLEAR report states that incorporating drug-releasing technology into a soft contact lens may significantly improve treatment compliance over eye drops.

Hui says the report also delves into the challenges to contact lens drug delivery including the lens/drug combination to optimise the uptake and release profile.

Notably, according to the report, if a drug molecule has an exceptionally high affinity for the lens material, then it could result in an unacceptably prolonged drug-release profile once the lens is placed on the eye. The molecular weight of the drug may also impact the ultimate uptake and release of the drug.

“Very few concepts have gone into animal studies,” Hui says. “What can we do to change the release profile? We’re in the early stages of focusing on that.”

Hui and his colleagues note in the report that the scope and timing of clinical trials to demonstrate the safety and efficacy of a drug-releasing lens are a substantial hurdle.

“Combination devices already exist in other medical fields, but it is a newer field in eyecare. The FDA in the US recognises combination devices, whether they be combinations of drugs, devices or biological products. How a combination product is ultimately evaluated and by whom depends on its primary mode of action, which in some cases may not be readily apparent,” Hui says.

Not all new ideas succeed, however. As it has become increasingly apparent that the tear film contains a wide range of biomarkers that may help diagnose systemic diseases, the potential for a contact lens-based diagnostic device has entered the equation.

“There is a laundry list of biomarkers that can be detected in the tear film, including glucose levels in the case of diabetes, and changes in combination of specific proteins in cancers,” Hui says.

The concept of a contact lens-based glucose sensor to monitor diabetes, in lieu of the gold standard finger-prick method, rose to popularity in 2014 but the hype has waned since a collaboration between Google and Novartis fell by the wayside in 2018 due to technical challenges.

“The physiology didn’t work out, because of the delay between changes in blood glucose levels and tear glucose levels, which is potentially fatal if patients were relying on those measures to determine insulin doses,” Hui says.

Amniotic membrane therapy paired with contact lenses

An amniotic membrane therapy that sits under a bandage contact lens as a delivery device is also gaining traction.

Known as amniotic membrane therapy, skilled specialty contact lens practitioner Ms Margaret Lam says this is new to Australia and has only been accessible in recent months.

Lam is a therapeutically-endorsed optometrist with multiple professional roles, including head of professional services at George and Matilda Eyecare, an Adjunct Senior Lecturer at UNSW School of Optometry and Vision Science, and a director on the national board at Optometry Australia.

Amniotic membrane
Regenerative amniotic membrane therapy. The new AmnioTek Vision (right) features a hole in the centre to minimise blurred vision. Image: ISP Surgical/Designs For Vision.

She is also national president of the Cornea and Contact Lens Society of Australia (CCLSA), an organisation with a history of introducing new techniques in contact lens technology to the wider profession. In keeping with this reputation, CCLSA is hosting an introductory lecture into the application of amniotic membranes for both ophthalmologists and optometrists in mid-July.

BCLA’s CLEAR report touches on this emerging technology, noting that the use of contact lenses as a stem cell delivery device has been demonstrated, with the contact lens vehicle doubling as a protective bandage following grafting.

“Limbal epithelial stem cells have been shown to reliably transfer from the contact lens to the ocular surface and an initial study of three patients with limbal stem cell deficiency reported a 100% success rate at a 12-month follow-up,” the CLEAR report states.

Margaret Lam CCLSA contact lens
Margaret Lam.

Describing amniotic membrane therapy as “an amazing new technology – the application of amniotic membrane therapy via a bandage contact lens is a new therapy with the potential to improve cases of severe corneal damage”, Lam says there are several specific indications when it would be used.

“Any potential corneal pathophysiology not healing well is indicated for amniotic membrane application including corneal ulcers, and potentially, peripheral corneal ulcer,” Lam says.

“It can also be used for dry eye cases with recalcitrant dense superficial punctate keratitis. Amniotic membrane is certainly a treatment that can be considered for many types of severe dry eye – amniotic membranes won’t necessarily help all patients with dry eye, but it would particularly help those with staining and those with systemic anti- inflammatory conditions associated with dry eye.”

Another application is for recurrent corneal erosion and epithelial membrane basement dystrophy (EMBD) with a recurrent corneal erosion component.

“In the past, to apply the amniotic membrane was a complex surgical intervention, applied as an end-stage procedure when all other options were exhausted,” Lam says.

Today, using donor placenta tissue that is wafer thin – as thin as a sheet of cellophane – and dry, which is also screened, sterilised and safe to use under a bandage contact lens, the therapy has entered a different ball game.

“The benefit and difference now is that this amniotic membrane therapy is in a more accessible form, applied under a bandage contact lens. It is no longer a surgical procedure. Instead, it can be administered by an optometrist or ophthalmologist that has been appropriately trained,” Lam says.

Regenerative amniotic membrane therapy has recently become accessible in Australia and New Zealand through ISP Surgical, a Thailand-based company that has developed custom dehydrated amniotic membrane grafts for many sub-speciality surgical applications.

ISP Surgical is also working with I-stem from France on a proposal to trial AMT grafts populated with “Stem Cells” in the future. Designs For Vision is the ISP Surgical/AmnioTek Brand Distributor in Australia and MEDIX21 Surgical in New Zealand.

Lam explains that a bandage contact lens comes with the allograft kit.

“This is very new, and practitioners are still deciding which is the most compatible contact lens that works best with this membrane therapy.”

Amniotic membrane therapy is not listed on the Medicare Benefits Schedule (MBS), and each application currently needs to be given special approval by the TGA, making accessibility an issue, Lam says.

“In order to access amniotic membrane therapy, eyecare practitioners have to apply to the TGA on a case-by-case basis, for each and every patient they wish to treat with this therapy. The problem is, for optometry approval, TGA approval can take between three to five days to come through however, the sooner the membrane can be applied, in acute cases, the better the outcome for the patient.”

Customisation 

A future that would allow eyecare practitioners to design and fit a completely customised contact lens is now a reality for optometrist and contact lens designer Mr Lachlan Hoy.

Hoy is a clinical optometrist at Innovative Eye Care – a business he purchased in 2010 with practices in Adelaide and Woodville – where he predominantly consults with contact lens patients.

When he is not fitting custom-made contact lenses, he is running the R&D lab as managing director of EyeSpace Lenses, a team dedicated to developing end-to-end software systems for the design, supply and manufacture of bespoke contact lenses.

Lachlan Hoy.
Lachlan Hoy.

Hoy says radical improvement in instrumentation and technology of the metrology of the eye – measuring the shape, tomography and optical wavefront of the eye – is resulting in more eyes being capable of wearing contact lenses, and with greater improvement in vision.

“We can now intricately fit soft and rigid contact lenses. From where I sit, we’re able to take individual measurements to create a one-off product, a completely custom-made lens,” Hoy says.

Hoy says EyeSpace is working with optometrists from Australia, New Zealand, the US, Latin America and Africa, as well as with ophthalmologists in China and Russia, to produce completely customised contact lenses for a wide range of patients from keratoconus to orthokeratology.

“The number of instruments coming on to the market that map and measure the eye is increasing every year; the technology is more sophisticated, it can measure more, which can contribute to better results. By capturing a 3D map of the eye, you can manufacture a contact lens that fits first time, eliminating the need for a trial set,” Hoy says.

From his R&D lab in Adelaide, Hoy is closely watching the development of smart contact lenses.

“Last year Mojo Vision unveiled their smart scleral lens incorporating a microprocessor, image sensor, 70,000 pixel display 480nm in size, with a tiny solid state battery which can be recharged when placed in its case at the end of the day, and then paired to your computer or phone,” he says.

“Smart contact lenses seem futuristic, but it is becoming reality, with Sony, Google, and Amazon all working in this space in recent years.”

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