Shanduro yeSyellen yeziso ndeye chati yekuongorora maziso inoshandiswa nevanyori vekucherechedza maziso kuti vaone kuonekwa kwakanaka, kana kuti murwere anogona kuona sei pasina rubatsiro. Dr Hermann Snellen akatanga chiratidzo chemaziso muna 1862.
Zvose Pamusoro peSani Yemaziso Yenyoka
Iyo Snellen chati cheziso ndeyanozivikanwa, yakarongwa chinyorwa chemashoko makuru uye maduku. Icho chinyorwa chinowanikwa nemiganhu 11 ye mabhuku ekuvhara, kutanga nekanyora kamwe chete mumutsara wepamusoro.
Nhamba yeakanyorwa pamutsara mumwe nomumwe inowedzera ichifamba kubva kumusoro kusvika pasi. Uhu hwemavara huri kuderera zvishoma nezvishoma, zvichibvumira mamwe tsamba pamutsara wega wega unotevera. Mhemberero yeStellen yechiso chekuona inoshandisa mashandisi aya anotevera: C, D, E, F, L, O, P, T, uye Z.
Kutarisa Kuona Kubudirira
Kana uchitaridzirwa kuonekwa kwakanaka, murwere anovhara ziso rimwe uye anoverenga zvinonzwika netsamba pa chati, achitanga kumusoro uye achienda kune zasi. Mutsara muduku wemakamba ayo murwere anoverenga nenzira yakarurama anogadzira maziso anooneka muziso risati raonekwa. Chiyero chinodzokororwa neimwe ziso, uye ipapo nemaziso ose pamwechete. Kutarisa kwekuona kune dzimwe nguva kunoratidzirwa sa 20/20, kana nhamba yakafanana, zvinoreva kuti mabhuku maduku kudarika zvakajeka pane chati.
Mhinduro
Migumisiro yekuongororwa kwako kwechibvumirano (chati yekuverenga) ichasarudza kunaka kwemaziso ako. Zvawakaratidzwa zviratidzo zvako (acuity) zvicharatidzwa sechikamu chiduku.
Zvikamu zviduku zvinoratidzwa kuruboshwe rwemutsara mumwe nomumwe uye kuziva kuti iwe unogona sei kuona. Kana iwe ukagona kuverenga zvakajeka kumutsara wechishanu, somuenzaniso, chiratidzo chako chicharatidzwa seine 20/40 chiratidzo; kana iwe ukagona kuverenga zvakajeka kumurongo wechinomwe, chiratidzo chako chicharatidzwa sa 20/25.
Kuti ududzire kuverenga kwako, funga nezve nhamba mumakumbo.
Somuenzaniso, mumwe munhu ane maonero 20/60 anogona kuverenga pamamita makumi maviri kubva pane izvo munhu ane chiratidzo chakanaka aigona kuverenga pamamita makumi matanhatu kubva ipapo. Mazuva ano mapurisa ekuongorora maekisi akachengetedzwa nemashandisirwo emagetsi ekuverenga, zvichiita kuti zvive nyore kubudisa kuverenga kwakarurama.
Zvaunofanira Kuziva
Kune zvikamu zvakawanda zvechirongwa chevanhu, sevana vaduku, vasingagoni kuverenga tsamba dzezvinyorwa zvinyorwa. Zvimwe zvemashoko anokosha ane zvidhori kuti aone panzvimbo yezvinyorwa zvinyorwa kana nhamba. MuUnited States, zvikamu zve 20/40 kana zviri nani zvinotarisirwa kuendesa motokari pasina kushandiswa kwekugadzirisa lenzi. Chiratidzo chinotyisa che 20/200 (kana kuti chakaipa) chinotarisa kuti munhu anenge ari bofu pamutemo .
Shanduro yeSyellen yemaziso inogona kuwanikwa uye inoshandiswa paIndaneti pakusarudza unhu hwako hwekuona.
Shenjerera, zvisinei, nokuti zvinogona kuva zvakaoma kugamuchira mhinduro yakarurama nevakawanda zvakasiyana-siyana zvekuongorora uye zvirongwa zvezvirongwa zviripo. Nzira yakanakisisa yekuziva kuti yako ndeyechokwadi yakajeka ndeyekuti uone kuongororwa kweziso kunoitwa neunyanzvi.