Directions:Fillineachblankwithaproperwordchosenfromthebox.Eachwordcanbeusedonlyonce.Notethatthereisonewordmorethanyouneed.
A.countingB.determinedC.distractionD.environmentalE.focusF.moderateG.naturallyH.performingI.worseningJ.comprehensivelyK.significant
Myopia,orshort-sightedness,isaconditioninwhichdistantobjectsappearblurred,butcloserobjectscanusuallybeseeninsharpfocus.Itsbiologicalbasisisaneyethat,duringchildhood,hasgrowntoolongforitsopticalpower.Thefocalplaneforimagesofdistantobjectsendsupinfrontoftheretina,causingout-of-(31)______perception.
Myopiawasonceregardedasalmosttotallygenetically(32)______.ButitsprevalencehasincreasedspectacularlyinurbanmainlandChina,HongKong,Taiwan,Singapore,JapanandSouthKorea,where80-90%ofthosecompletinghighschoolarenowshort-sighted.Thisisupfrom20-30%onlytwogenerationsago.Sincegenepoolsdonotchangethatfast,thesemassivechangesmustbedueto(33)______change.In2005,we(34)______reviewedtheresearchonmyopiaandfoundacorrelationwitheducation.(Thiswasnotaparticularlynovelinsight;suchalinkwaspostulatedasfarbackasKeplerin1604.)Wefoundlocationswithahighprevalenceofmyopiawerealltopperformersinsurveysofinternationaleducationaloutcomes
Fortunately,notallhigh-(35)______locations,Australiaamongthem,showedahighprevalenceofmyopia.Thisshowsthathigheducationaloutcomesdonotnecessarilyleadtomyopia.Wealsohypothesisedthatallhumanpopulationgroupshadatendencytodevelopmyopiaunderparticularenvironmentalconditions.Indeed,NorthAmericaandEuropehaveseengrowingratesofmyopia,althoughtheyarestillnowherenearashighasinEastandSoutheastAsia.
Acommoncutoffforhighmyopiais-5diopters..Thismeansvisionisblurredbeyond20cmfromtheeyes.Suchsevereorhighmyopiaincreaseswithageandcanleadtovisualimpairmentthatcan’tbecorrected.Theprevalenceofhighmyopiahasnowreached20%inyoungadultsinEastandSoutheastAsia,whichforeshadowsmajorincreasesinvisual(36)______andblindnessastheseyoungadultsage.Sopreventionofmyopiahasbecomecrucial,particularlyforEastandSoutheastAsia.
Australiahas(37)______lowlevelsofmyopiawithalifestylethatemphasisesoutdoorsactivities.Youngchildrenreportspendingtwotothreehoursadayoutside,not(38)______timeoutdoorsatschool.However,thereareformidablebarrierstoachievingthisbenchmarkinlocationswherespendingtimeoutdoorsisseenasa(39)______fromstudy.Policyresponsesmustthereforealsoaimtoslowtheprogressionofmyopia,thephenomenoninwhichmildto(40)______myopiabecomesmoresevereduringchildhood.Thereiscurrentlycontroversyoverwhethertimeoutdoorsslowsprogression,butstrongseasonaleffectsonprogressionsuggestthatitmay.