Txhawm rau xaiv ib nkawm looj tsom iav, koj yuav tsum xav txog ntau yam. Ntxiv nrog rau kev xav txog kev nplij siab ntawm kev hnav, lwm qhov tseem ceeb tshaj plaws yog xim ntawm lub lens. Cov xim ntawm cov tsom iav cycling tuaj yeem muab faib ua cuaj xim:
Lub lens daj yog tsim rau siv nyob rau hauv qhov tsaus ntuj nti teeb pom kev zoo thiab thaum hmo ntuj kom txo tau lub teeb pom kev ntawm lub lens thiab ua kom lub teeb pom kev zoo;
Cov lo ntsiab muag dub, tiv thaiv ultraviolet rays, lim tawm glare thiab teeb pom kev zoo rau lub qhov muag, thiab tiv thaiv qhov muag;
Cov xim tsis muaj xim yog qhov zoo tagnrho rau huab cua pos huab lossis grey;
Liab lossis txiv kab ntxwv yog qhov zoo tshaj plaws tag nrho, uas tuaj yeem ua rau thaj chaw ib puag ncig kom meej meej.
