Mukalowa m'sitolo yogulitsira magalasi ndikuyesera kugula magalasi, mumakhala ndi mitundu ingapo ya ma lens kutengera ndi mankhwala omwe mwalandira. Koma anthu ambiri amasokonezeka ndi mawu akuti single vision, bifocal ndi progressive. Mawu awa amatanthauza momwe magalasi omwe ali m'magalasi anu amapangidwira. Koma ngati simukudziwa mtundu wa magalasi omwe mankhwala anu amafunikira, nayi chidule chachidule kuti chikuthandizeni kuyamba.
1. Kodi Magalasi Oona Chimodzi Ndi Chiyani?
Lenzi imodzi yowonera ndi lenzi yomwe imakhala ndi mankhwala amodzi. Mtundu uwu wa lenzi umagwiritsidwa ntchito polemba mankhwala kwa anthu omwe ali ndi vuto la kuona pafupi, kuona patali, astigmatism, kapena omwe ali ndi zolakwika zosiyanasiyana. Nthawi zambiri, magalasi amodzi owonera amagwiritsidwa ntchito ndi anthu omwe amafunikira mphamvu yofanana kuti awone patali komanso pafupi. Komabe, pali magalasi amodzi owonera omwe amaperekedwa pa cholinga china chake. Mwachitsanzo, magalasi awiri owerengera omwe amagwiritsidwa ntchito powerenga okha amakhala ndi lenzi imodzi yowonera.
Lenzi ya masomphenya amodzi ndi yoyenera ana ambiri ndi achikulire achichepere chifukwa nthawi zambiri safunika kusintha momwe amaonera kutengera mtunda wawo. Mankhwala anu a magalasi amodzi nthawi zonse amakhala ndi gawo lozungulira ngati nambala yoyamba pa mankhwala anu ndipo angaphatikizeponso gawo la silinda kuti athetse vuto la astigmatism.
2. Kodi Magalasi a Bifocal N'chiyani?
Magalasi a bifocal ali ndi madera awiri osiyana owongolera maso. Maderawa amagawidwa ndi mzere wosiyana womwe umakhala mopingasa kudutsa lenzi. Gawo lapamwamba la lenzi limagwiritsidwa ntchito poyang'ana mtunda, pomwe gawo la pansi limagwiritsidwa ntchito poyang'ana pafupi. Gawo la lenzi lomwe limagwiritsidwa ntchito poyang'ana pafupi likhoza kupangidwa m'njira zingapo zosiyanasiyana: gawo la D, gawo lozungulira (looneka/losaoneka), gawo lopindika ndi mzere wa E.
Magalasi a bifocal nthawi zambiri amagwiritsidwa ntchito ngati munthu ndi wosowa kwambiri amene sangathe kuzolowera magalasi opita patsogolo kapena ana aang'ono omwe maso awo amagundana akamawerenga. Chifukwa chomwe akuchepera kugwiritsa ntchito ndichakuti pali vuto lofala lomwe limabwera chifukwa cha magalasi a bifocal otchedwa "image jump", pomwe zithunzi zimaoneka ngati zikudumpha pamene maso anu akuyenda pakati pa magawo awiri a lens.
3. Kodi Magalasi Opita Patsogolo Ndi Chiyani?
Kapangidwe ka ma lens opita patsogolo ndi katsopano komanso kotsogola kuposa ma bifocal. Ma lens awa amapereka mphamvu yopita patsogolo kuchokera pamwamba pa lens kupita pansi, zomwe zimapangitsa kuti maso azisinthasintha mosavuta pa zosowa zosiyanasiyana za maso. Ma lens opita patsogolo amatchedwanso kuti bifocal yopanda mzere chifukwa alibe mzere wooneka pakati pa magawo, zomwe zimapangitsa kuti azioneka bwino kwambiri.
Komanso, magalasi owonera pang'onopang'ono amapangitsanso kusintha kosavuta pakati pa mtunda, pakati, ndi pafupi ndi gawo la mankhwala anu. Gawo lapakati la lenzi ndi labwino kwambiri pazochitika zapakati monga ntchito ya pakompyuta. Magalasi owonera pang'onopang'ono ali ndi mwayi wopanga njira yayitali kapena yayifupi. Njirayi kwenikweni ndi gawo la lenzi lomwe limakupatsani mwayi wowona mtunda wapakati.
Mwachidule, magalasi a masomphenya amodzi (SV), a bifocal, ndi opita patsogolo amapereka njira zosiyanasiyana zowongolera masomphenya. Magalasi a masomphenya amodzi ndi oyenera mtunda umodzi (pafupi kapena kutali), pomwe magalasi a bifocal ndi opita patsogolo amalankhula za masomphenya apafupi ndi akutali mu lenzi imodzi. Magalasi a bifocal ali ndi mzere wooneka womwe umalekanitsa magawo apafupi ndi akutali, pomwe magalasi opita patsogolo amapereka kusintha kosalekeza pakati pa mtunda wopanda mzere wooneka. Ngati mukufuna zambiri, chonde musazengereze kutilankhulana nafe.