Nkuko izina ribigaragaza, indorerwamo ya bifocal ifite luminosity ebyiri.Mubisanzwe, bikoreshwa mukubona intera, nko gutwara no kugenda;Ibikurikira nukubona hafi yumucyo, kubona hafi, nko gusoma, gukina terefone igendanwa nibindi.Iyo lens ya bifocal imaze gusohoka, mubyukuri byafatwaga nkubutumwa bwiza bwa myopia + presbyopia, bikuraho ibibazo byo gutoranya no kwambara kenshi, ariko nkuko abantu babikoresha, usanga inenge za lensike ya bifocal nayo ifite byinshi.