This blog was kindly contributed by Annegret Dahlmann-Noor, Consultant and Director of the Children’s Eye Service at Moorfields Eye Hospital in London and Honorary Clinical Associate Professor at UCL. You can find Annegret on Twitter @AnnegretNoor.
Myopia, or short-sightedness, has always been common among young people in higher education. Many students wear glasses or contact lenses and regard these as minor inconveniences. Sports and swimming goggles with optical corrections are now available, extending clear focus from educational to leisure activities.
However, in recent years myopia has become an increasing public health concern and is set to become ever more important for the next generations of students. Over the past 50 years, the proportion of young people in the UK who develop myopia has doubled, with children typically being found to have myopia in the pre-teens, followed by rapid progression of their degree of short-sightedness. In the UK, a sixth of 12-to-13 year olds, and over a quarter of 15-to-16 year olds and young adults now have myopia. The prevalence is far higher in young people in East Asian countries. For example, in Taiwan over 90 per cent of 18 year old young men have myopia. There are predictions that by 2050, half the world population may have myopia.
Myopia typically worsens while children and young people are growing up and in many it continues to progress while they are in full-time education. With myopia now developing at a younger age, the number of young people who develop dangerously high levels of short-sightedness is increasing. The World Health Organisation (WHO) considers a level of minus 5.00 diopters has as ‘high myopia’, linked to a risk of developing sight-threatening complications later in life. Previous epidemiological studies in the Netherlands calculated a 39 per cent risk of permanent sight loss by the age of 75 years for people with high myopia.
The three main complications are all caused by the increasing elongation of the eyeball which is the underlying anatomical change in myopia: the eyeball increases in length and the eye tissues are stretched. This can lead to retinal breaks and detachments, breaks in the retinal layers for central vision (myopic macular degeneration) and stretching of the optic nerve fibres, with increased vulnerability to the pressure inside the eye (glaucoma). There is increasing recognition that not only people with ‘high myopia’ are at risk, but that every diopter matters: with each diopter increase in the prescription, the risk of developing myopic macular degeneration later in life increases by 67 per cent. Irreversible sight loss means a terrible loss of quality of life, with an inability to continue both leisure and work-related activities: reading, sports, navigating unfamiliar environments.
The causes for the current rise in myopia rates are not entirely clear. Convincing evidence indicates that less exposure to sunlight, part of an ‘urban’ lifestyle, plays an important role in the onset of myopia at an earlier age. Conversely, spending more time outdoors can delay the onset of myopia and can also – to a small extent – reduce its progression.
In addition to spending less time outdoors, young people now also spend more of their indoor time on ‘near activities’. Not only has the educational workload increased, with more daily hours spent on books and screens for study purposes, but leisure activities increasing also take place on small, often handheld devices. Games and movies are viewed and played on desktops, laptops, tablets and smartphones. Mobile and handheld devices in particular are omnipresent and used throughout the day. Parent surveys indicate that children spend an hour or less per day outdoors or on sporting activities. Epidemiological studies in China clearly demonstrated that the pandemic-inflicted reduction in time outdoors, coupled with a dramatic increase in time spend on screens for schooling and education led to earlier onset and faster progression of myopia, comparing ‘pandemic’ with ‘pre-pandemic’ year groups. On an anecdotal basis, optometrists in the UK report seeing increasing numbers of young children with myopia now.
As light exposure and near work are factors within our control, simple solutions have been suggested. While there is no hard evidence about how much of a difference these make to the development of myopia, it is easy to see how lifestyle advice might benefit not only the eyes, but the overall person and their physical, social and mental wellbeing. The Myopia Group in Rotterdam recommends a modification of advice originally developed for adults with ‘computer vision syndrome’: after 20 minutes of near work, gaze in the distance for at least 20 seconds and spend 2 hours outside per day (and close work should be performed at a distance of at least 30 cm). This simple piece of advice, the ‘20-20-2 rule’, is now frequently recommended by eye health practitioners. A group in Taipei developed the ‘30-30-out’ suggestion: keep a viewing distance of 30 centimetres, have a break after 30 minutes of near work and spend your breaks outdoors.
With the increase of online education in universities, it would be beneficial for students’ current and future wellbeing if developers of education technologies incorporated these pieces of advice when building virtual learning environments and other core pieces of technology that support learning. This could be as simple as recommending a rest at pre-programmed intervals. Learning specialists are likely to agree, as regular breaks during studying are thought to enhance learning, reflection and retention of new content.