Kaua e manukanuka — ehara i te mea me mau koe i ngā karu arotahi-rua, i ngā karu arotahi-toru rānei e kore e pai. Mō te nuinga o te tangata, he pai ake te kōwhiringa karu arotahi kore-raina.
He aha ngā arotahi whakamua?
Ko ngā karāhe arotahi whakamua he karāhe mōhiti kanohi maha-arotahi kore-raina e rite ana te āhua ki ngā karāhe tirohanga kotahi. Arā, mā ngā karāhe arotahi whakamua koe e āwhina ki te kite mārama i ngā tawhiti katoa me te kore e kitea ngā "rārangi arotahi-rua" whakarihariha (me te tautuhi i te pakeketanga) e kitea ana i roto i ngā arotahi-rua me ngā arotahi-toru noa.
Ka huri haere te mana o ngā karāhe arotahi whakamua i ia pūwāhi ki ia pūwāhi i runga i te mata o te karāhe arotahi, ka whakarato i te mana tika mō te kite mārama i ngā mea i te tata ki ngā tawhiti katoa.
Ko ngā arotahi-rua, i tētahi atu taha, e rua noa iho ngā mana o te karāhe arotahi — tētahi hei kite mārama i ngā mea tawhiti, me tētahi atu mana i te haurua o raro o te karāhe arotahi hei kite mārama i te tawhiti pānui kua tohua. Ko te hononga i waenga i ēnei rohe mana rerekē ka tautuhia e tētahi "rārangi arotahi-rua" e kitea ana e tapahi ana i waenganui o te karāhe arotahi.
Ko ngā karāhe arotahi whakamua, i ētahi wā ka kiia ko ngā "kanapa arotahi-rua kore-raina" nā te mea kāore i a rātou tēnei rārangi arotahi-rua e kitea ana. Engari he tino matatau ake te hoahoa arotahi-maha o ngā karāhe arotahi whakamua i ngā arotahi-rua, i ngā arotahi-toru rānei.
Ko ngā karāhe arotahi matatau kounga teitei te nuinga o te wā e whakarato ana i te whakamarie me te mahi pai rawa atu, engari he maha atu anō ngā waitohu me ngā mahi tāpiri, pērā i te karāhe arotahi matatau whakaahua-ira, te karāhe arotahi matatau puru-tapa me ētahi atu, me ngā momo rauemi rerekē. Ka kitea e koe tētahi e tika ana māu i runga i tā mātou whārangi.https://www.universeoptical.com/progressive-lenses-product/.
He maha ngā tāngata ka tīmata ki te hiahia mō ngā mōhiti kanohi maha-arotahi i muri i te 40 tau. Koinei te wā ka whakaitihia ai te kaha o te kanohi ki te kite mārama i te taha tata e te huringa koroheketanga noa e kiia nei ko te presbyopia. Mō te hunga whai presbyopia, he nui ngā painga tirohanga me te whakapaipai o ngā mōhiti kanohi whakamua ki te whakataurite ki ngā mōhiti kanohi rua me ngā mōhiti kanohi toru tuku iho.
Ko te hoahoa maha-arotahi o ngā karu arotahi whakamua e tuku ana i ēnei painga nui:
Ka mārama te tirohanga i ngā tawhiti katoa (kaua i ngā tawhiti tirohanga e rua, e toru rānei).
Ka whakakorea te "peke whakaahua" whakararuraru e puta mai ana i ngā arotahi-rua me ngā arotahi-toru. Koinei te wāhi e huri ohorere ai te mārama me te tūnga o ngā mea ina neke ō kanohi i ngā rārangi e kitea ana i roto i ēnei arotahi.
Nā te mea kāore he "rārangi kanohi rua" e kitea ana i roto i ngā karāhe arotahi whakamua, ka hoatu e rātou he āhua taitamariki ake i ngā karāhe arotahi rua, i ngā karāhe arotahi toru rānei. (Koinei pea te take he nui ake te hunga e mau ana i ngā karāhe arotahi whakamua i te hunga e mau ana i ngā karāhe arotahi rua me ngā karāhe arotahi toru i ēnei rā.)