Ndi gawo lomwe lili m'munsi mwa lens, lens ya bifocal imasonyeza mphamvu ziwiri zosiyana za dioptric, zomwe zimapereka odwala masomphenya omveka bwino komanso akutali.
Mosasamala chifukwa chomwe mukufunikira mankhwala owongolera masomphenya pafupi, ma bifocals onse amagwira ntchito mofanana. Gawo laling'ono m'munsi mwa lens lili ndi mphamvu zofunikira kuti mukonze masomphenya anu apafupi. Ma lens ena nthawi zambiri amakhala owonera patali. Gawo la mandala lomwe limaperekedwa pafupi ndi kukonza masomphenya likhoza kukhala limodzi mwa mawonekedwe angapo.