China Daily (Hong Kong)

The out­doors can pro­tect kids from my­opia

- The author is an in­ter­na­tional public health con­sul­tant.

Short­sight­ed­ness or my­opia, a con­di­tion where dis­tant ob­jects ap­pear blurry while close ob­jects ap­pear nor­mal, is a vis­ual de­fect that is be­com­ing in­creas­ingly se­ri­ous among Chi­nese chil­dren. The es­ti­mated my­opia rate in China is 31 per­cent. How­ever, among chil­dren and teenagers it is much higher.

Since my­opia can have health-dam­ag­ing con­se­quences if left un­cor­rected, it must be dealt with more ef­fec­tively by par­ents as well as health au­thor­i­ties.

My­opia, how­ever, is not a China-spe­cific is­sue; it has a global im­pact. Ac­cord­ing to re­searchers, rates of my­opia have dou­bled, even tripled, in most East Asian coun­tries over the past 40 years. Although Singapore is con­sid­ered to have the high­est rate in the world, with about 80 per­cent of the pop­u­la­tion af­fected by it, the preva­lence of my­opia among In­dian peo­ple is only 6.9 per­cent.

The rates of my­opia have been ris­ing in Western coun­tries such as Ger­many and the United States, too. In the US, as well as in some Euro­pean coun­tries, the rate has al­most dou­bled in the past 50 years. Ac­cord­ing to some es­ti­mates, one-third of the world’s pop­u­la­tion, or 2.5 bil­lion peo­ple, could be af­fected by my­opia by 2020. Some ex­perts say we are close to ex­pe­ri­enc­ing a my­opia epi­demic.

A com­bi­na­tion of both ge­netic and en­vi­ron­men­tal fac­tors seems to be re­spon­si­ble for my­opia, and the risk fac­tors in­clude do­ing work that fo­cuses on close ob­jects, spend­ing a lot of time in­doors and a fam­ily his­tory of this con­di­tion. Although for years many peo­ple con­sid­ered ge­netic fac­tors to be re­spon­si­ble for my­opia, stud­ies show en­vi­ron­men­tal fac­tors could also be re­spon­si­ble.

One im­por­tant fac­tor re­spon­si­ble for my­opia could be the amount of time spent study­ing and do­ing home­work. Some ex­perts say chil­dren who spend long hours read­ing and do­ing home­work are more likely to de­velop my­opia. This the­ory, how­ever, doesn’t hold wa­ter. Close work, although it might be a fac­tor, alone is not re­spon­si­ble for the con­di­tion.

Re­searchers at the Uni­ver­sity of Cam­bridge in Bri­tain have found that a lack of out­door ac­tiv­i­ties is linked to my­opia. Sun­light seems to have a pro­tec­tive ef­fect on chil­dren dur­ing their crit­i­cal years of de­vel­op­ment, that is, when their eye­balls are still grow­ing. The rea­sons for this ef­fect, how­ever, are not yet known.

Ian Morgan, a re­searcher at the Aus­tralian National Uni­ver­sity in Can­berra, says chil­dren who spend enough time out­doors are less likely to de­velop my­opia even if they study more than those chil­dren who al­most al­ways stay in­doors. Morgan es­ti­mates chil­dren need to spend about three hours a day un­der good light con­di­tions to avoid my­opia. The prob­lem with this ap­proach, how­ever, is that in many places and in dif­fer­ent sea­sons chil­dren can­not spend much time out­doors. Some ex­per­i­ments are be­ing con­ducted to al­low more chil­dren to play and study in bet­ter ar­ti­fi­cial light con­di­tions. No clear-cut results, how­ever, have been achieved yet. Some re­searchers say chil­dren should spend more time play­ing out­doors, be­cause it has the ad­di­tional ben­e­fit of im­prov­ing their mood, in­creas­ing their level of phys­i­cal ac­tiv­ity and de­creas­ing the like­li­hood of obe­sity, an­other sig­nif­i­cant prob­lem among chil­dren. To de­tect the prob­lem of my­opia early, all chil­dren should have a com­pre­hen­sive eye ex­am­i­na­tion by the age of three, with par­ents pay­ing spe­cial at­ten­tion to any changes in their eye­sight. And, of course, chil­dren’s eye­sight could ben­e­fit from less home­work and less use of elec­tronic gad­gets, though both are dif­fi­cult propo­si­tions in to­day’s com­pet­i­tive so­ci­eties. As with any other health prob­lem, pre­ven­tive mea­sures against my­opia can be more ef­fec­tive and less costly than a cure.

 ?? MA XUEJING / CHINA DAILY ??
MA XUEJING / CHINA DAILY

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