Choyamba, tiyeni timvetsetse kuti ndi mandala opita patsogolo, ndipo gulu lake la mandala limatha kufotokozedwa ngati chilichonse.Ngati agawanika kuchokera poyambira, magalasi amatha kugawidwa kukhala magalasi amodzi, ma lens a bifocal, ndi ma multifocal lens.Ma lens opita patsogolo a multifocal, akudziwanso ...
Werengani zambiri