Uma ungena esitolo sezibuko bese uzama ukuthenga izibuko, unezinhlobo eziningana zezinketho zelensi kuye ngokuthi umuthi wakho uthini. Kodwa abantu abaningi bayadideka ngamagama athi umbono owodwa, i-bifocal kanye ne-progressive. Lawa magama abhekisela endleleni amalensi asezibukweni zakho aklanywe ngayo. Kodwa uma ungaqiniseki ngohlobo lwezibuko ozidingayo umuthi wakho, nansi incazelo emfushane yokukusiza uqalise.
1. Ayini Amalensi Okubona Okukodwa?
Ilensi yokubona eyodwa empeleni ilensi ephethe umuthi owodwa kadokotela. Lolu hlobo lwelensi lusetshenziselwa umuthi kadokotela kubantu ababona eduze, ababona kude, abane-astigmatism, noma abanenhlanganisela yamaphutha okubona. Ezimweni eziningi, izibuko zokubona eyodwa zisetshenziswa abantu abadinga amandla afanayo ukuze babone kude futhi basondele. Kodwa-ke, kunezibuko zokubona eyodwa ezibekelwe injongo ethile. Isibonelo, izibuko zokufunda ezisetshenziselwa ukufunda kuphela ziqukethe ilensi yokubona eyodwa.
Ilensi yokubona eyodwa ilungele iningi lezingane kanye nabantu abadala abasebasha ngoba ngokuvamile abadingi ukulungisa ukulungiswa kokubona kwabo ngokusekelwe ebangeni labo. Ilensi yakho yokubona eyodwa ihlala ifaka ingxenye eyindilinga njengenombolo yokuqala ku-kadokotela wakho futhi ingafaka nengxenye yesilinda yokulungisa i-astigmatism.
2. Ayini Amalensi E-Bifocal?
Amalensi e-bifocal anezindawo ezimbili ezihlukene zokulungisa umbono. Izindawo zihlukaniswe umugqa ohlukile ohlala ngokuvundlile phezu kwelensi. Ingxenye ephezulu yelensi isetshenziselwa ibanga, kanti ingxenye engezansi isetshenziselwa ukubona eduze. Ingxenye yelensi enikelwe ekuboneni eduze ingakhiwa ngezindlela ezimbalwa ezahlukene: ingxenye ye-D, ingxenye eyindilinga (ebonakalayo/engabonakali), ingxenye yejika kanye ne-E-line.
Amalensi e-bifocal avame ukusetshenziswa uma umuntu engumuntu ongavamile ongakwazi ukuzivumelanisa namalensi aqhubekayo noma ezinganeni ezincane amehlo azo aqhekeka lapho zifunda. Isizathu sokuthi angasetshenziswa kakhulu ukuthi kunenkinga evamile ebangelwa amalensi e-bifocal abizwa ngokuthi “i-image jump”, lapho izithombe zibonakala zigxuma njengoba amehlo akho ehamba phakathi kwezingxenye ezimbili zelensi.
3. Ayini Amalensi Aqhubekayo?
Umklamo wamalensi aqhubekayo musha futhi uthuthuke kakhulu kune-bifocal. Lawa malensi anikeza amandla aqhubekayo kusukela phezulu kwelensi kuya phansi, enikeza ukuguquka okungenamthungo kwezidingo ezahlukene zokubona. Amalensi ezibuko zamehlo aqhubekayo abizwa nangokuthi ama-bifocal angenamugqa ngoba awanayo imigqa ebonakalayo phakathi kwezingxenye, okwenza abe mnandi kakhulu.
Ngaphezu kwalokho, izibuko zamehlo eziqhubekayo nazo zidala ushintsho olubushelelezi phakathi kwebanga, eliphakathi nendawo, kanye nezingxenye eziseduze zemithi yakho kadokotela. Ingxenye ephakathi yelensi ilungele imisebenzi ephakathi nendawo njengomsebenzi wekhompyutha. Izibuko zamehlo eziqhubekayo zinenketho yokuklama i-corridor ende noma emfushane. I-corridor empeleni iyingxenye yelensi ekunika ikhono lokubona amabanga aphakathi nendawo.
Ngamafuphi, amalensi ombono owodwa (i-SV), amalensi amabili, kanye namalensi aqhubekayo ngalinye linikeza izixazululo ezihlukile zokulungisa umbono. Amalensi ombono owodwa afanele ibanga elilodwa (eliseduze noma elikude), kuyilapho amalensi amabili kanye namalensi aqhubekayo ebhekana nokubona okuseduze nokukude kulensi eyodwa. Amalensi amabili anomugqa obonakalayo ohlukanisa izingxenye eziseduze nebanga, kanti amalensi aqhubekayo anikeza ukuguquka okungenamkhawulo, okunezigaba phakathi kwamabanga ngaphandle komugqa obonakalayo. Uma udinga olunye ulwazi, sicela ukhululeke ukuxhumana nathi.