Science

Soak in the Sun, sleep early and tight to avoid myopia

Young achievers:  There is a need for awareness among parents to control the use of near-vision devices such as smartphones. .

Young achievers: There is a need for awareness among parents to control the use of near-vision devices such as smartphones. .

Myopia or shortsightedness is turning out to be an epidemic across India, and indeed even more in Southeast Asia. It occurs because of the potential role of myopic genes and also local environmental conditions such as the prolonged ‘near work’ and/or less sunlight exposure, and not because of any infection due to harmful germs. It will not become a worldwide pandemic, as COVID-19 has. Yet, drastic changes in lifestyle (becoming more indoor-centric) and the timing and levels of sunlight we receive, it is time to take measures to counteract myopia, which may well become a global pandemic.

What is myopia?

Myopia occurs when the eyeball becomes longer, relative to the focusing power of the cornea and the lens; this leads to focus not on the surface of the retina, but at a point before it. This leads you to find it difficult to focus distant objects clearly, though you can see close-up objects such as while reading and using the computer use (allaboutvision.com). In the year 2000, about 25% of the world’s population was near-sighted or myopic, but it is expected to increase to above 50% by 2050 (30 years from now).

Dire predictions

Based on the current increasing prevalence of myopia in India, scientists from the L.V. Prasad Eye Institute (LVPEI) predict that 64 million children (aged 5-15 years) living in urban regions of the country alone will have myopia by the year 2050, if no interventions are made to control it. While many factors are known to counteract this problem, recent studies indicate less time spent outdoors to be a risk factor for myopia. Ambient levels of light during daytime tend to be over 10 to 100 times brighter than that indoors. There are various ways in which such outdoor brightness helps protect the human eye from becoming myopic. (1) If you are in an open space, and not performing any ‘near work’, the stress on the eye is reduced. (2) Outdoor environment provides equal optical stimuli to various parts of the peripheral retina (the posterior part of the eye) and also enables exposure to different colours (the so called VIBGYOR) equally well, while indoor lighting using artificial sources that cut off specific wavelengths. (3) Upon bright illumination in sunlight, the pupil reduces its size and reduces blur, and increase the depth of focus. (4) Sunlight exposure helps the biology of the eye, helping it to produce more vitamin D. (5) Exposure to bright light releases the hormone dopamine, which controls the length of the eye ball; the shorter it is, myopia might set in. (In this connection, see Rohit Dhakal and Pavan K. Verkicharla: “Increasing time in outdoor environment could counteract the rising prevalence of myopia in Indian school-going children”, Current Science, 119,1-4, 2020).

Intense educational pressure from the family and teachers to achieve academic excellence, excessive homework, attending coaching classes (invariably held late in the evening, or before school timing for entrance exams) rob high school children of sunlight, leading to the myopia epidemic becoming an endemic, and a sub-global pandemic in Central and East Asian subcontinent.

Policy suggestions

Rohit Dhakal and Pavan Verkicharla (myopia researchers from LVPEI) have made some obvious and public health policy suggestions, which can be implemented right away, particularly now that we have the National Education Policy getting ready for implementation.

These are: Mandatory 60 minutes of recess time in all schools during the school hours every day, by locking the classrooms to keep the students in sunlight, starting from primary level to the high schools. Have a structured recess time incorporated into all their curricula. Make it mandatory for schools to have enough space for playgrounds. Create public awareness among parents about the importance of proper eyesight and control the use of near-vision devices such as smartphones. Recommend/promote community centres in each locality to organise outdoor programmes weekly or at least twice a month.

Many reasons

All these are obvious and yet not followed, due to economic, financial, real estate and sociological reasons. But at least schools and colleges in the hands of the State and Central governments should attempt to do so. The future stares at us – lest we become short-sighted or myopic in more than one sense.

Even as I write, comes a new publication which says that suggests that sleeping late is a risk factor for myopia development amongst school-aged children in China (X N Liu et al.; Scientific Reports (2020) 10:17194 https://doi.org/10.1038/s41598-020-74348-7. They point out that years of study have identified a number of risk factors for myopia, such as family history, genetics, urban living environment. Recent studies also indicate that shorter sleep duration and poorer sleep quality are associated with the development of myopia. They disturb the circadian rhythm of the body, particularly in the brain, and also strain the retina. Thus, early to bed and deep sleep are preventive measures against the onset of myopia.

Again, we know that this, too, is becoming difficult with online teaching through web classes, and with the use of television as an instructive medium, particularly for poorer children in rural areas who do not have smartphones. While this may be inevitable during these lockdown days, it should not become an inevitable teaching method, and schools must reopen and conduct classes during daytime.

(I thank Dr. Pavan Verkicharla for sharing views and advice, and contributing to this article.)

dbala@lvpei.org


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Printable version | Jun 10, 2022 4:41:59 pm | https://www.thehindu.com/sci-tech/science/soak-in-the-sun-sleep-early-and-tight-to-avoid-myopia/article33048781.ece