Maemong a mangata a ho fokola ha mahlo, myopia (haufi-ufi) kapa hypermetropia (ho talima holimo) e hlokomeloa. Ho khethoa ha likhalase tlas'a maemo a joalo a se nang boikarabelo ho reretsoe ho li fokotsa ka thuso ea ho hasanya kapa ho bokella likhalase.
Tsela ea ho khetholla diopter ha u khetha likhalase?
Ha ho khethoa likhalase mokuli o le hole le limithara tse tšeletseng tafoleng e khethehileng e tloaelehileng. Leihlo le leng le le leng le hlahlojoa ka thoko. Ho tloha holimo, mokuli o bala mangolo a mola o mong le o mong. Mokha oa ho qetela o baloa o bontša mahlo a bonono. Ka mor'a moo, ho fokolloa (nako e telele), ebe joale e matla (likhutšoane tse khutšoanyane) likhalase tse sebelisoang mahlong. Mokuli o bala mohala oa ho qetela hape, oo a neng a ka o bona. Se matla ka ho fetisisa se khabisitsoeng ka khalase se bontša tekanyo ea ho talima holimo.
Haeba pono ena e senyeha ho tloha ka khalase ea khalase, joale tekanyo ea myopia e ka khoneha. Sena se etsoa ka thuso ea khalase ea concave. Haeba khalase ea concave e sa thusoe, sesosa sa ho senyeha ha mahlo a bonono se hlakisoa ho phaella moo.
Mefuta ea likhalase tse nang le diopters
Likhalase tsa mefuta-futa tse nang le diopters - likhalase-chameleons (photochromic). Ba sebelisa li-lense tsa photochromic, tse fetola 'mala, e.g. ho fifala, ka ketso ea mahlaseli a ultraviolet. Hlokomela hore likamoreng tse khantsoeng li-chameleons ha lia fifala, kaha khalase ea silicate ha e lumelle hore phallo ea ultraviolet e fete.
Likhalase tsa likamele tse tšoanelehang li khantša ka metsotso e meraro, li fifetse metsotso e le 'ngoe. Tabeng ena, lensense li tlameha ho fetola 'mala ka nako e le' ngoe.
Lisebelisoa tse sireletsang li ka boela tsa e-ba le li-diopters. Li sebelisoa lipapaling tse feteletseng, libaesekele, lipapali tsa motlakase, ho fofa lithabeng, ho pota-pota marulelo, joalo-joalo. Tšobotsi ea bona ke hore li entsoe ka boitsebiso bo tšoarellang haholo, kahoo likhalase tsena li sireletsa mahlo hore a se ke a fumana likaroloana tse tiileng.
Litlhapi tse sireletsang ho sesa le diopters li sireletsa mahlaseli a kotsi, 'me seaparo se khethehileng ka hare ho lens se ba sitisa ho phalla. Ha u khetha likhalase tsena, ho lokela ho nkoa hore metsi a ntlafatsa phello ea lilense.
Likhalase tsa mahlo tsa ho khanna le diopters, ntle le ho lokisa mahlo, li lokela ho netefatsa hore ho felisoa ha limela (polarization), ho etsa phapang e molemo. Likhalase tse joalo li ka boela tsa etsoa ka thepa ea photochromic.
Bakeng sa batho ba nang le mahlo a sa boneng, hona joale u ka khetha kapa u khetholla litela tsa mahlaseli ka diopters. Ho qoba liphello tse sa phutholohang, ho hlokahala hore u khethe mefuta ea likhalase tse sephara (e le hore lilense li le sefofane se le seng ka pel'a mahlo).
Ba bangata ha ba sebetsa likhalase tsa k'homphieutha tse sebelisang k'homphieutha, tseo ka lebaka la lihlopha tse khethehileng, li fokotsa khatello mahlong. Haeba u e-na le mathata a mahlo, ho khoneha ho kopanya likhalase tse joalo ka lensisi tsa lisele. Kgetho e 'ngoe ke ho sebelisa likhalase tsa k'homphieutha ka diopters tse loketseng.
Haeba u sitoa ho bona hantle, ka hona ho fokotsa mahlo ho fapane, likhalase tse nang le diopters tse sa tšoaneng li khethiloe.
Bakeng sa batho ba bangata ba nang le mahlo a sa boneng, ho hlokahala lipatlisiso tse peli tsa likhalase - bakeng sa "sebaka" le bakeng sa "haufi" (ha u bala). Empa ho na le monyetla oa ho sebelisa likhalase tse le 'ngoe ka li-dioptries, ka bobeli bakeng sa ho bala le maemong a mang. Li-lense li khalase tsena li bitsoa multifocal.
Lintlha tse nang le diopter tsa zero (likhalase tse tloaelehileng) li sebelisoa e le mokhoa oa ho feshene, ho hatisa setšoantšo.
Haeba u batla likhalase tsa feshene ka dioptries, ka kopo hlokomela hore nakong e tlang ka feshene e tla ba likhalase "leihlo la kako", "leihlo la dragonfly", likhalase ka liforeimi tse kholo, le mekhabiso.