E whā ngā momo matua o te whakatikatika tirohanga—te emmetropia, te myopia, te hyperopia, me te astigmatism.
Ko te emmetropia he tirohanga tino pai. Kei te tino tika te whakawhiti a te kanohi i te mārama ki te retina, ā, kāore e hiahiatia he whakatikatika mōhiti.
Ko te myopia e mōhiotia whānuitia ana ko te tirohanga tata. Ka puta tēnei ina roa rawa te kanohi, ka arotahi te mārama ki mua o te retina.
Hei whakatika i te myopia, ka tohua e tō tākuta kanohi he karāhe minus (-X.XX). Ka panaia e ēnei karāhe minus te pūwāhi arotahi whakamuri kia tika ai te tūnga ki runga i te retina.
Ko te myopia te momo hapa whakaata tino kitea i roto i te hapori o ēnei rā. Inaa, e kiia ana he mate urutā puta noa i te ao, nā te mea kei te piki haere te tokomaha o te taupori e pāngia ana e tēnei raruraru i ia tau.
Ka taea e ēnei tāngata te kite i te mea nui mai i te tata, engari ko ngā mea i tawhiti he āhua pōuriuri.
Mō ngā tamariki, ka kite pea koe i te tamaiti e uaua ana ki te pānui i te papa i te kura, e pupuri ana i ngā rauemi pānui (waea pūkoro, pukapuka, iPad, me ētahi atu) e tata rawa ana ki ō rātou mata, e noho tata rawa ana ki te pouaka whakaata nā te mea "kāore e taea e rātou te kite", e pīataata ana rānei, e mirimiri ana rānei i ō rātou kanohi.
Ko te hyperopia ia, ka puta mai i te wā e taea ai e te tangata te kite i tawhiti, engari ka uaua pea ki te kite i ngā mea i te taha tata.
Ko ētahi o ngā amuamu tino kitea mō te hunga e pangia ana e te hyperope, ehara i te mea kāore e taea e rātou te kite, engari ko te mamae o te upoko ka pā mai i muri i te pānui pukapuka, te mahi rorohiko rānei, ko te ngenge, te ngenge rānei o ō rātou kanohi.
Ka puta te hyperopia ina poto rawa te kanohi. Nō reira, ka aro paku te mārama ki muri i te retina.
Mēnā he tirohanga noa, ka arotahi te ahua ki te mata o te retina. Mēnā he tirohanga tawhiti (hyperopia), kāore tō kornea e huri tika i te mārama, nō reira ka taka te pūwāhi arotahi ki muri i te retina. Nā tēnei ka āhua pōuriuri ngā mea e kitea tata ana.
Hei whakatika i te hyperopia, ka tohua e ngā tākuta kanohi he karaihe tāpiri (+X.XX) hei kawe i te pūwāhi arotahi ki mua kia tau tika ki te retina.
He kaupapa anō te mate kanohi pūngāwerewere. Ka puta te mate kanohi pūngāwerewere ina kore te mata o mua o te kanohi (te kornea) e tino porotaka.
Whakaarohia he korēne noa e rite ana ki te poitūkohu kua tapahia kia rua. He porowhita tino pai, he ōrite hoki i ngā taha katoa.
He rite te āhua o te kornea astigmatic ki tētahi hua manu kohuatia kua tapahia kia rua. He roa ake tētahi meridian i tētahi atu.
Mā te āhua rerekē o ngā meridian o te kanohi e rua, ka rerekē ngā pūwāhi arotahi e rua. Nō reira, me hanga he karāhe mōhiti hei whakatika i ngā meridian e rua. E rua ngā tau o tēnei whakahaunga. Hei tauira - 1.00 - 0.50 X 180.
Ko te tau tuatahi e tohu ana i te kaha e hiahiatia ana hei whakatika i tētahi meridian, ko te tau tuarua e tohu ana i te kaha e hiahiatia ana hei whakatika i tētahi atu meridian. Ko te tau tuatoru (X 180) e kī ana i te wāhi e takoto ai ngā meridian e rua (ka taea te awhe mai i te 0 ki te 180).
He rite ngā kanohi ki ngā tohu o ngā maihao—kāore he mea e rua e ōrite ana. E hiahia ana mātou kia kite koe i tō āhua pai rawa atu, nō reira, mā te whānuitanga o ngā momo karāhe ka taea e tātou te mahi tahi ki te kimi i te otinga tino pai hei whakatutuki i ō hiahia takitahi.
Ka taea e Universe te tuku i ngā karaihe arotahi pai ake hei whakatika i ngā raruraru kanohi i runga ake nei. Kia arotahi ki ā mātou hua:www.universeoptical.com/products/