I-bifocal iyi-lens enamaphuzu amabili okugxila, ngokuvamile i-lens eyodwa yokubuka izinto ezikude, ne-lense eyodwa yokubuka izinto eziseduze. I-bifocal yaziwa nangokuthi i-lens multi-focal. U-Ben Franklin ubizwa ngokuthi umsunguli we-lens initial ye-bifocal.
Okwenza Ungadinga i-Bifocal
I-Presbyopia: Kunzima ukuyiqonda kuze kube yilapho ufinyelela kuleso sikhathi empilweni yakho, kodwa uma usu- 40 ubudala, sihlakulela i- presbyopia .
I-Presbyopia ibangela ukuncipha kancane kancane ekutheni kugxile ezintweni eziseduze nokufunda ukuphrinta okuncane. Ekuqaleni, abantu babona ubunzima bokufunda ezindaweni ezimnyama nokufunda usayizi webhodlela lomuthi wokuphrinta. Abantu abane-presbyopia bayaqaphela nokuthi kunzima kakhulu ukugxila ebangeni ukuya eduze. Njengoba isikhathi esiningi sihamba futhi besondela eminyakeni yobudala engu-42 kuya ku-45, iqala ukuba yinkinga ebaluleke kakhulu empilweni yabo nakho konke abazama ukukufunda noma ukubheka ebangeni eliseduze kuba nzima kakhulu. Odokotela abaqondi kahle inqubo kodwa bayakholelwa ukuthi i-presbyopia ivela ngenxa yenhlanganisela yomzimba (umzimba we-ciliary) ngaphakathi kweso lingasebenzi futhi i-lens itholakale ngaphakathi kwamehlo ethu, iba yinkinga engapheliyo. Umphumela wokubamba ukungabi namandla okugxila ezintweni eziseduze. Impendulo yale nkinga iwukuba i-optometrist yakho ibeke i-bifocal. Kuleli phuzu, sidinga ingxenye eyodwa ye-lens ukuze sigxile kude futhi ingxenye eyodwa ukugxila kuseduze.
Ukungasebenzi okubalulekile: Abanye abantu badinga i-bifocal kungenxa yokungasebenzi kahle . Ezinye izingane zakha isimo lapho zingakwazi ukugxila kalula kude ukusuka kude. Babuzwa nokukhathala okukhulu ngenkathi bezama ukulondoloza ukugxila ekufundeni noma ukufunda ekilasini.
Esotropia Yokuvakasha: Esinye isizathu esenza ezinye izingane zigqoke i-bifocal kungenxa yesimo esibizwa ngokuthi i-esotropia yokuhlala. I-esotropia yokuvakasha ingenye yezinhlobo ezivame kakhulu ze-strabismus. Ngokuvamile, lezi zingane zibheke kakhulu. Lezi zinezingane zine- esotropiya noma iso eliwehlisiwe elibangelwa imizamo yamehlo njengoba zizama ukucacisa futhi zibuyisele ukubhekwa phambili. Abanayo ukungalingani phakathi kwesistimu ye-muscle converging system kanye nesistimu yokugxila. I-bifocal ivame ukunciphisa inkinga ngokuphelele.
Izinhlobo ze-Bifocal Lenses
Amalensi we-Bifocal atholakala ezinhlotsheni eziningana ezahlukene.
- I-flat-top - I-flat top bifocal inesigaba esincane esenziwe njengezinyanga ezinhlanu noma incwadi "D" eceleni kwayo. Libekwe eceleni nasenhla ngasekugcineni kwe-lens. Kuye okuthandayo, isiguli singakhetha phakathi kwesigaba se-25 mm noma ingxenye engama-28 mm. Ingxenye yesigaba inelayini ebonakalayo ku-lens.
- I-round seg - I-round bifocal ingxenye engama-22 noma engu-24 mm nxazonke ukuya phansi kwe-lens. Lokhu kuhlanganiswa kwenzelwe ukuvumela lowo ogqokile ukuba afinyelele endaweni yokufunda yendawo kancane lula. Amagceke azungezile awavamile ukugqoka namuhla.
- I-Blended - i-bifocals ehlanganisiwe yayithandwayo ngaphambi kokuba kube ne-non-line bifocals. Zivame ukufakwa kwendima ejikelezayo lapho izingxube zihlanganiswa khona nazo zonke ezinye i-lens. Ngenkathi i-optician eqeqeshiwe ikwazi ukuyibona kalula, kuwo wonke umhlaba kubonakala kancane kunobuso obuphezulu besibocal.
- I-Executive - I-executive bifocal iyinhlangano ye-linux bifocal lapho ingxenye engaphezulu (ibanga) ingxenye ye-lens ihlukaniswe ngokuphelele engxenyeni engezansi (eduze) ingxenye yelensi ene-lens ebonakalayo elula yonke indlela ehamba ngendwangu. Lezi zithandwa kakhulu ngabantu ababenomsebenzi omkhulu kanye nedeskini emsebenzini wabo emsebenzini futhi bacatshangelwa ukuba banikeze indawo engaphezulu yokugxila kuyo. Basuke bengathandeki kakhulu eminyakeni yamuva ngenxa yomugqa ongaqondakali ohamba ngendlela yonke ngaphesheya kwe-lens. Futhi, ochwepheshe be-optical bafunde ukuthi abantu abazange basebenzise kakhulu i-lens endaweni yangakini njengengqondo eyodwa kanye ne-flat-top bifocal eyenziwa kahle.
- Okuqhubekayo - Amalense okuqhubekayo amalensi ongase uzwe ukukhangiswa njenge-bifocal engabonakali, engenamandla noma engekho emgqeni. Ama-lens okuqhubekayo athula kancane kancane noma aguquka amandla okufunda njengoba i-lensi ivaliwe phansi phansi kwe-lens ngaphandle kwemigqa ebonakalayo. Esikhundleni sokuba nokunqunywa okungahambi kahle kusuka kude kuya kuseduze, kukhona ukushintsha kancane kancane emandleni. Amalensi okuqhubekayo ngoba athandwa ngokushesha ngoba anika ukubukeka kwentsha.