Combatting the epidemic of short-sightedness

Myopia is a very common eye problem affecting people of all ages worldwide. By 2050, about half of the world’s population will suffer from myopia, and East Asia will be the region with the highest prevalence—with a rate as high as 90%, according to the International Myopia Institute.

The “myopia boom” is worrying in Hong Kong. PolyU scientists at the Research Centre for Sharp Vision (RCSV) have been working on technologies to combat the global epidemic of myopia.

It is not just a “blurry vision thing”

Some people may consider myopia to be a minor nuisance that can be addressed with eyeglasses or laser eye surgery. However, the importance of professional eye care has been greatly downplayed. Myopia control must be a priority and should start early. Myopia typically starts developing in a person before the age of 10, and it progresses during childhood and adolescence. It happens when the eyeball is too long, or the cornea is too curved for its optics. Prolonged eye strain, including pressure from long periods of screen viewing, can make vision worse. The stretching of the eyeballs can gradually thin out the retina or other eye structures. This increases the risk of sight-threatening diseases such as glaucoma, cataracts, retinopathy and blindness.

The rise of myopia in young children is alarming. About 40% of 8-year-old Hong Kong school children surveyed in a recent study were afflicted with myopia, and a 2.5-fold increase in myopia incidence among school children has been observed during the COVID-19 pandemic.

The pandemic-related myopia boom in school children may have stemmed from their sedentary lifestyle, and particularly the reduction in outdoor time and increase in screen time during the pandemic. Other factors such as heredity also contribute to short-sightedness. In fact, the strikingly higher prevalence of myopia in East Asia than in other regions sheds light on some cultural factors that contribute to myopia. Scholars in mainland China have verified a correlation between the demanding school year and low/moderate myopia. The achievement-oriented environments in East Asian cultures, with their emphasis on academic achievement at an early age, rigorous schooling systems, frequent examinations, long study hours, and little outdoor leisure time, may have worsened eye health.

Beyond wearing eyeglasses: Vision defocus for myopia control

Wearing eyeglasses improves visual acuity, but it does not address the root of the problem. Currently, several options are available for controlling myopia. These include spectacle lenses and soft contact lenses.

PolyU-developed technologies curbing the myopia epidemic

PolyU researchers have been working on myopia-curbing technologies for many years, with very positive results. Prof. TO Chi-ho (former RCSV Director), Prof. Carly LAM (RCSV Member) and Dr Dennis Tse (RCSV Member) have developed “myopic defocus” technology, which applies a micro-optical structure to optical lenses for projecting constant myopic defocus to the retina, hence slowing the progression of myopia. The technology is applied to spectacle lenses and soft contact lenses, to produce the Defocus Incorporated Multiple Segments (DIMS) Spectacle Lens and Defocus Incorporated Soft Contact (DISC) lens, respectively.

The eye’s growth is regulated by homeostatic control mechanisms. Physical optical inputs guide the growth of the eye and regulate its size. The defocus technology is based on the principles of peripheral myopic defocus and simultaneous vision: blurry images are introduced on the peripheral retina, while clear vision is maintained on the central retina. Thus, the technology slows myopia progression while allowing users to see clearly at all viewing distances. In a clinical trial, the DIMS Spectacle Lens was found to slow myopia progression by 60% in Hong Kong school children aged 8–13. The new treatment method can also help lower the risk of myopia-related eye diseases like retinal detachment and glaucoma among people suffering from extreme myopia, which affect about 938 million individuals globally.

A two-decade effort to bring myopia defocusing technology to all children without limits

The PolyU-led “myopic defocus” projects can be tracked back to the 2000s, when researchers spent seven years (2007–14) testing and confirming the myopia defocus concept using animal studies, and evaluated the effectiveness of the DISC Lens in school children using randomised controlled clinical trials. For the next two years, the team turned their attention to the DIMS Spectacle Lens.

By 2016, both myopia defocusing inventions were mature and ready for technology transfer and commercialisation. In the same year, Prof. To and a PolyU graduate founded a university-supported start-up, Vision Science and Technology Co. Ltd (VST). The lenses were first rolled out to the market in 2018. Currently, the DIMS Spectacle Lenses are available to all eye care practitioners under the brand name MiyoSmart for prescription in Hong Kong, mainland China, as well as 30 other countries and regions in Asia, Europe and North America. This PolyU-led invention can potentially benefit over 1 million children worldwide. The team also collaborated with non-profit organisations in Hong Kong to bring the DIMS Lens to children from 400 underprivileged families.

The defocus technology has been awarded numerous prizes at the Geneva International Exhibition of Inventions over the years. At the 46^th Expo (2018), the DIMS lens was awarded a Grand Prize (overall championship); the Prize of the Legal Company Gorodissky & Partners, Russia; and a Gold Medal with Congratulations of the Jury. The DISC Lens won a Grand Prize and a Gold Medal with Jury’s Commendation at the 39^th Expo (2011). In collaboration with Prof. Benny CHEUNG (RCSV Associate Director), the team recently developed the Nano Multi-ring Defocus Incorporated Spectacle (NMDIS) lens, which evolved from the DISC technology with the use of ultra-precision manufacturing techniques. The NMDIS lens received a Prize of the State of Geneva and a Gold Medal with Congratulations of the Jury at the 48^th Expo.

Red light that reverses near-sightedness

Another technology that is attracting growing interest in the field of ophthalmology is repeated low-level red-light therapy (RLRL). The RCSV has provided empirical evidence for this emerging treatment. Prof. HE Mingguang—Chair Professor of Experimental Ophthalmology and Henry G. Leong Professor in Elderly Vision Health—collaborated with researchers based in mainland China and Australia for a randomised controlled trial. Prof. He is currently the Director of RCSV.

According to traditional ingrained belief, myopia is progressive and irreversible. However, the RLRL study by Prof. He and his colleagues has shown just the opposite. The study proved that RLRL can effectively control myopia progression and can be delivered in the form of a home-use device that emits low-level red laser radiation. In the one-year randomised clinical trial, the RLRL treatment was found to shorten the axial length and reverse the spherical equivalent refraction in nearly a quarter of the studied participants.

Eyes need to breathe: Oxygenation for myopia control

“RLRL works by using a light feeder that emits red light with a wavelength of 650 nanometres, to stimulate and improve the blood circulation on the ocular fundus. This thickens the choroid and improves oxygen supply to the sclera, hence inhibiting the axial length elongation of the eyeball and controlling the progression of myopia,” Prof. He said, describing the principles that underly the therapy. 

The study compared children who wore ordinary single-vision lenses and received RLRL to those with lenses only. The experimental group received three-minute RLRL twice daily for five weekdays every week over a 12-month period. The RLRL in the experimental group was conducted at home, and the children performed the treatment using a desktop device under parental supervision.

RLRL is safe when red light with low intensity is used for a certain period of time. Results from the clinical trial showed that the experimental group and control group had similar results in best-corrected visual acuity, an important indicator of treatment safety. This implies that the studied children’s visual function was intact and unaffected by the low-intensity red light radiation.

Interdisciplinary eye research that enables sharper sight

PolyU researchers from the School of Optometry (SO) have been working on myopia studies since 2003. The establishment of RCSV in 2021 introduced a new, interdisciplinary perspective to eye research. Myopia is one of the central research foci at RCSV, and the Centre is seeking a deeper, more comprehensive understanding of the mechanism that controls eye elongation, along with effective therapeutic solutions to myopia.

The massive success of defocus technology from many years of hard work by PolyU and industry partners marks the need for stronger efforts to advance, transfer and commercialise the technology. In August 2022, Prof. To stepped down from the director position to fully focus on VST developments, advancing the technology further. Taking the baton was Prof. KEE Chea-su, Associate Director of RCSV, and Head and Professor in SO. While serving as RCSV Interim Director (August 2022–September 2023), Prof. Kee steered the Centre toward major successes—in the 2022/23 year, RCSV generated 13 publications, secured external funds of HK$16M, was granted a patent, and received a donation from Fujian Zhongshi Jiaming Medical Management Co., Ltd, for deepened collaboration in ophthalmology research in mainland China.

Prof. Kee sees team engagement and mentorship as particularly important in interdisciplinary research. “It is important to strengthen and encourage interdisciplinary research collaboration among junior RCSV members. The involvement of more experienced members in these projects would be a good catalyst for this collaboration,” said Prof. Kee.

The collaboration encompasses not only research, but also knowledge transfer and talent development. “In the future, we will link up with leading vision research institutes in Hong Kong, mainland China and other regions for strategic research partnerships, and we will engage the industry for long-term collaboration and the establishment of joint research labs. We will also develop an innovative curriculum for postgraduate research students, offer scholarships and organise conferences. We aim to attract the brightest minds worldwide to join and contribute to the Centre, and increase the visibility of RCSV’s work to the global research community.”

Passing the torch of vision research excellence

In October 2023, RCSV welcomed Prof. He as the new director. He was recently named on the 2023 Ophthalmologist Power List, which recognises the 100 most influential people worldwide in the field of ophthalmology, among those who have demonstrated ten years of excellence and impact.

One of Prof. He’s research foci is the development and translation of new treatments, as well as novel ways of delivering eye care, into clinical practice, with a particular focus on functional eye diseases and artificial intelligence. This emphasis and his pursuit of clinical breakthroughs in eye care have stemmed from his background as a trained medical doctor. Prof. He received his Bachelor of Medicine, Bachelor of Surgery (MBBS) from Sun Yat-sen University, Guangzhou. He obtained two master degrees, in public health and ophthalmology, and later a PhD degree in ophthalmology from the University College London. Over the years, Prof. He has actively contributed to global eye research with his important appointments. Previously, he served as Head of Ophthalmic Epidemiology at the Centre for Eye Research Australia, and Director of the WHO Collaborating Centre for Prevention of Blindness (Australia). He is the Founding President of the Asia Pacific Tele-Ophthalmology Society, Founding Council Member of the Asia Pacific Myopia Society, and Deputy Secretary-General of the Asia Pacific Academy of Ophthalmology.

In his new capacity, Prof. He is determined to elevate the Centre even further with his ambition to “create something entirely new”. “We need to think about new ways to do our science, new ways to work with industrial partners, new ways to treat the problems, and then translate these new approaches into products for clinical benefit,” he said.