Zomwe zimatchedwa lens zimagwira ntchito zimatanthawuza magalasi apadera omwe amatha kubweretsa makhalidwe abwino kwa anthu enieni m'madera ndi magawo ena, ndipo amatha kusintha maonekedwe ndi kupanga mzere wowonekera bwino, womveka komanso wofewa.
Magalasi osintha mitundu: kufunafuna malingaliro a mafashoni, oyenera myopia, hyperopia, astigmatism, ndipo amafuna kuvala magalasi nthawi imodzi. Magalasi amtundu wa Hanchuang amasintha mtundu mwachangu mkati ndi kunja, amakana kuwala kwa UV ndi buluu, osati ozizira kwambiri!